A Polyrotaxane-Based Solid Electrolyte with Cableway-Type Li-ion Transport

A Polyrotaxane-Based Solid Electrolyte with Cableway-Type Li-ion Transport | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article A Polyrotaxane-Based Solid Electrolyte with Cableway-Type Li-ion Transport Zheng Liang, Zhangqin Shi, Yuhang Liu, Xinyang Yue, Qinghui Zeng, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9434833/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Solid polymer electrolytes (SPEs) are promising candidates for all-solid-state lithium batteries, yet their practical application is hindered by the low room-temperature Li-ion conductivity. Herein, we propose a “Cableway”-like transport for the high-Li-conductive SPE by substituting the regular Li-coordination side chains of the main network with flexible rotaxane structures. With reduced constraints imposed by covalent crosslinking, the 24-crown 8-ether, as the “cable car” of Li ions, could dynamically slide along the backbone of the neutralized polyrotaxane-based SPE (NPR-SPE). This promotes the Li-ion transfer between the branches or rings while maintaining mechanical properties and dissipating local energy. The NPR-SPE exhibits a Li-ion conductivity of ~1.28 mS cm −1 at 30 °C, five times higher than the SPE configured by the polyethylene glycol branches, although they share a similar main cross-linking network. The LiFePO 4 cell with NPR-SPE attains a reversible capacity of 68.8 mAh g −1 at 10 C and demonstrates stable 2400 cycles with efficient dendrite restriction. Physical sciences/Chemistry/Energy Physical sciences/Chemistry/Polymer chemistry/Supramolecular polymers solid polymer electrolyte polyrotaxane Li-ion transport molecular motility solid-state battery Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. INTRODUCTION The global transition towards sustainable energy has intensified the quest for next-generation electrochemical energy storage technologies 1,2 . All-solid-state lithium metal batteries (ASSLMBs) stand out as pivotal candidates, promising unparalleled safety and energy density 3,4 . Among solid-state electrolytes, solid polymer electrolytes (SPEs) offer distinct advantages, including superior mechanical flexibility and interfacial compatibility, which effectively mitigate issues like interfacial degradation and lithium dendrite growth prevalent in inorganic systems 5-7 . However, SPEs, such as polyethylene oxide (PEO), show a room-temperature Li-ion conductivity (RT-LC) lower than their liquid or ceramic counterparts 8,9 . More importantly, under the seesaw effect between ionic conductivity and mechanical properties in SPEs arising from the molecular motility, formidable challenges loom on the horizon for the real-world application of SPEs in achieving an expedient polymer matrix that provides both appreciably high RT-LC and structural integrity 10-14 . The Li-ion transport of SPEs relies on chain-segmental motion and inter-/intra-chain ion hopping between coordinating sites 15-17 . Therefore, local polymer fluctuations are paramount for facilitating Li-ion transfer between coordination structures and for the relative Li-ion motion along chains. Covalent (chemical) crosslinking is a conventional strategy to suppress the polymer crystallization and improve the mechanical properties of SPEs (Figure 1a). Yet, the cross-linkers act as pinning sites, severely restricting segmental fluctuations and, consequently, diminishing RT-LC 18-20 . To reintroduce dynamics, researchers have integrated non-covalent interactions (e.g., hydrogen and ionic bonds) into covalent networks 21-24 . However, the non-covalent (physical) crosslinking suffers from its weak structural reversibility and mechanical properties (Figure 1b). It is apparent that the routine combination of chemical and physical crosslinking typically sacrifices one aspect of performance for the other, making it challenging to overcome the seesaw effect in SPEs 25,26 . The impasse of SPEs has directed attention to mechanically interlocked networks (MINs) as a transformative design paradigm (Figure 1c). Since MINs uniquely integrate the robust, locked-in architecture of covalent networks with the dynamic, unlocked character of non-covalent systems at the molecular level 27-29 , they exhibit more pronounced intrinsic advantages than conventional covalent and non-covalent crosslinking networks (Figure 1d). This sophisticated unification offers a promising route to circumvent traditional trade-offs. Seo’s group designed a partially crosslinked polyrotaxane based on α-cyclodextrin as a high-performance SPE, highlighting the potential application of MINs 30,31 . Our previous research proposed a molecular muscle SPE by crosslinking the [ c 2] daisy chain with polyethylene glycol, demonstrating the favorable effect of interpenetrating dibenzo-24-crown-8 wheels on the movement of the Li-coordinated backbones 10 . In spite of the improvements to date being quite satisfactory, particularly with regard to the ionic conductivity (Figure 1e and Table S1), a critical knowledge gap persists: the precise mechanism of Li-ion transport within MINs, whether dominated by the motion of the ring-encouraged network or the Li ion-coordinated rings themselves, remains elusive (Figure 1f). This lack of fundamental understanding severely limits the rational design of high-performance MIN-structured SPEs. In this work, we aim to address this core question by unveiling a unique “Cableway” transport mechanism in a polyrotaxane-based MIN. We propose and demonstrate that the customized 24-crown 8-ether of [2]rotaxane with high local fluctuations can act as the “cable car” of Li ions to facilitate the Li-ion transport (Figure 1g). By strategically designing and comparing a series of SPEs with identical main networks but varying side-chain architectures, including a neutralized polyrotaxane (NPR), its host–guest locked analogue (PR), a simple covalent network (CCN), and a covalent network with PEG side chains (CCB), we decouple the contributions of the mobile rings from the polymer network. Through a synergistic combination of rheology, two‑dimensional nuclear magnetic resonance (NMR), and molecular dynamics (MD) simulations, we demonstrate that the crown ether ring not only participates in Li-ion coordination but also enhances overall Li-ion transport by acting as a non-covalent branch, dramatically enhancing RT-LC without sacrificing mechanical properties. Therefore, the neutralized polyrotaxane-based SPE (NPR-SPE), serving as a prototype, exhibits Li-ion conductivity of ~1.28 mS cm −1 at 30 °C (Li-ion transference number of 0.88), outperforming its counterparts. When deployed in ASSLMBs at RT, NPR-SPE enables remarkable cycling stability (800 cycles), high-rate capability (68.8 mAh g −1 at 10 C), and effective dendrite suppression. 2. RESULTS & DISCUSSION 2.1. Structure design and characterization To better investigate the distinctive roles of movable 24-crown 8-ether (24C8) rings within polymer networks on Li-ion transport, we prepared four related samples with the same main crosslinking network but different side chains: MIN with polyrotaxane (PR), MIN with neutralized polyrotaxane (NPR), single covalent crosslinking network (CCN), and the CCN with PEG side chains (CCB) (Figure 2a). By leveraging host–guest recognition of a small-molecule template 32 , we develop an efficient strategy to prepare a crown ether-based polyrotaxane. This strategy relies on a crucial molecular axle decorated with four secondary ammonium salt sites. Upon mixing with 24C8, a portion of the rings forms pseudorotaxanes by binding to these sites, as shown in the synthetic routes summarized in Supplementary Section S2 and Figure S1–S19. The axle’s terminal alkene units react with thiol-functionalized 4-armed PEG via thiol–ene click chemistry, introducing the polymer chains and forming the targeted PR that preserves host–guest interactions and restricts ring slipping, as shown in Figure S20. Strategic deprotonation via immersion in potassium tert-butoxide/DMF solution neutralizes the secondary ammonium centers, liberating 24C8 macrocycles for unrestricted axial motion along polymer chains to yield NPR. Two control samples were prepared based on axles without the 24C8 ring. The CCN was obtained after the thiol–ene click chemistry and neutralization reaction (Figure S21). For CCB, short PEG side chains were introduced onto the secondary ammonium centers of the axle, followed by the same thiol–ene click chemistry and neutralization steps (Figure S22–S25). All networks share a similar crosslinking density (Figure S26). To verify the formation of pseudorotaxane precursors prior to network formation, 1 H NMR analysis was performed on mixtures of the molecular axle and 24C8 (Figure 2b). Significant chemical shift perturbations were observed upon mixing: protons adjacent to the secondary ammonium centers (H 3 and H 4 ) exhibited downfield shifts, while resonances associated with 24C8 shifted upfield 33 . These characteristic shifts are consistent with established host–guest recognition phenomena between 24C8 and secondary ammonium ions. Quantification of the threaded 24C8 was achieved by integrating the peak corresponding to the complexed macrocycle (H 5c ) and normalizing it against a characteristic, non-interfering peak on the axle. This analysis revealed that the stoichiometric ratio of 24C8 to axle critically influences the threading efficiency under the employed reaction conditions. Increasing the feed ratio increased the amount of captured 24C8. As shown in Figure 2c, the number of the 24C8 ring on the axle was near saturation when the feed ratio was 4:1. To construct a uniform ring distribution on the main network, the saturation ratio was employed for PR and NPR, introducing an average of three 24C8 macrocycles per axle molecule. Following deprotonation to generate NPR, Fourier-transform infrared (FTIR) spectroscopy confirmed the removal of PF 6 − counterions (Figure 2d). The disappearance of characteristic PF 6 − vibrational modes, specifically the P−F stretching peak at 842 cm −1 and the F−P−F bending peak at 559 cm −1 in the NPR spectrum, provides direct evidence for the successful neutralization of the secondary ammonium salts and subsequent dissociation of the anions from the polymer network. In the absence of host–guest recognition, the ring’s motion on NPR is more flexible than in PR. Therefore, we speculate that favorable Li-ion transport behavior could occur in the NPR-based SPE. The SPE was fabricated by immersing the polymer network in LiTFSI/THF solution (1:4 w/w) for 24 hours, followed by heating at 60 °C for 12 h to completely remove residual solvent (Figure S27). NPR-SPE has a defect-free morphology with a uniform thickness of ~100 μm, in which the LiTFSI species were homogeneously distributed throughout the polymer, as evidenced by F and S elemental mapping (Figure S28). The scanning electron microscope (SEM) images of other samples are collected in Figure S29. The polymer’s structure remained stable after adding the lithium salt. As revealed by the strain–stress profiles (Figure 2e and Figures S30), the polymer was soft after mixing with LiTFSI, which can be ascribed to the dynamic improvement by non-covalent interactions between Li + /TFSI − ions and the polar sites of the polymer. On the other hand, incorporating 24C8 increases SPE toughness, an effect correlated with the rotaxane’s dynamic sliding mechanism. 2.2 Li-ion coordination and transport To determine the RT-LC ( σ Li⁺ ) as depicted in Figure 3a, multiply the total ionic conductivity by the measured Li-ion transference number ( t Li⁺ ) of each SPE (Figure S31, S32). NPR-SPE incorporating freely sliding 24C8 rings exhibited a σ Li⁺ of ~1.28 mS cm −1 , which is much higher than other SPEs. Although the main PEG network of SPEs also contains Li-coordinated sites, its relatively weak dynamics at RT are not conducive to ion transport compared to the side chains. Given the lack of Li-coordinated side chains, the low σ Li⁺ of CCN is understandable. By contrast, for SPEs using PR and CCB, their lower σ Li⁺ than that of NPR-SPE is of interest for investigating side-chain movement and also suggesting the possibility of favorable Li-ion transport mechanisms in NPR-SPE. The Li-ion coordination environment within SPEs was analyzed using density functional theory (DFT) and molecular dynamics (MD) simulations. As shown in Figure 3b and Figure S33, the binding energy ( E b ) of the Li ion with the C−O−C side for the main PEG network and 24C8 ring is ~179.0 and ~221.8 kJ mol −1 , respectively. The 7 Li static NMR spectra confirm the coexistence of two distinct Li species with different chemical environments in NPR-SPE (Figure S34). Radial distribution function (RDF) profiles revealed a prominent, sharp peak corresponding to Li⁺∙∙∙O(24C8) interactions, indicating closer and more frequent coordination than in Li⁺∙∙∙O(PEG) (Figures 3c and 3d). Consistently, the mean squared displacement (MSD) of the Li ion in NPR-SPE is higher than that in CCN-SPE, quantitatively confirming the enhanced Li-ion mobility conferred by the presence of 24C8 rings (Figure 3e). Due to the enhanced Li-ion coordination by rings and the restriction on the transport of large-sized anions, NPR-SPE shows the highest t Li⁺ among the samples. These results indicate that the dynamic ring can not only participate in ion transport but may also construct a fast Li-ion transport channel. Both the skeleton and the ring can serve as ion transport sites in NPR-SPE. It is crucial to explore the impact of the ring on the dynamics of the main network to accurately identify its role in improving Li-ion transport. Master curves were obtained with a reference temperature of 30 °C through the time-temperature superposition (TTS) principle. All three samples (PR-SPE, CCB-SPE, and NPR-SPE) exhibited a typical elastic plateau across the measured frequency range, indicative of well-organized network structures (Figure 3f and Figure S35). Within the CCB-SPE network, the plateau modulus varied slightly among the samples, indicating that internal dissipation is primarily dominated by PEG chain friction. The modulus of PR-SPE is slightly higher than that of NPR-SPE, and its tan δ curve exhibits a steeper slope, demonstrating the greater elasticity and a more pronounced viscoelastic transition of PR-SPE 34 . This result is likely due to the free 24C8 rings facilitating segmental motion. Given the similar cross-linking densities across all samples, the above observation suggests that the presence of freely movable 24C8 rings enhances the overall mobility of the polymer to some extent. The results of the glass transition temperatures ( T g ) also confirm the “dynamic plasticization” effect of the 24C8 ring in NPR-SPE (Figure 3g). Differential scanning calorimetry (DSC) reveals a distinct T g trend: NPR-SPE < PR-SPE < CCB-SPE < CCN-SPE. While the short side chains of CCB-SPE provide plasticization through localized segmental activation, their efficacy falls short of the dynamic sliding of 24C8 rings. However, compared to the previous SPE using MIN, which integrates the ring into the overall network, the improvement in mechanical properties and dynamics of the NPR-SPE is relatively weak (Figure S36). This phenomenon can be attributed to the hanging-ring structure depended on the non-covalent interaction, affecting the main network less than the ring covalently connected to the network. Combined with the results of the notable increase in σ Li⁺ and the lower energy barrier of the ring than that of the main crosslinking network in molecular motion, it is reasonable to infer that the key contribution to the RT-LC stems from the movement of the ring as the Li-ion carrier, rather than the movement of the main network. To probe the dynamic coordination environment of Li ions at the molecular scale and its correlation with macroscopic transport properties, we employed electrochemical impedance spectroscopy (EIS) and 7 Li solid-state nuclear magnetic resonance (NMR) technology. The activation energy ( E a ) for ion transport was investigated using temperature-dependent EIS profiles 35,36 . Based on the Vogel–Tammann–Fulcher (VTF) fitting (Figure S37), NPR-SPE shows an E a of 42.6 kJ mol − 1 , lower than that of other SPEs (Figure 4a), aligning well with the results of the high σ Li⁺ of NPR-SPE at RT. The 7 Li NMR spin-lattice relaxation times ( T 1 ) of SPEs are shown in Figure 4b. The T 1 value for NPR-SPE, PR-SPE, CCB-SPE, and CCN-SPE is 0.167, 0.269, 0.261, and 0.325 s, respectively. A shorter T 1 generally indicates faster local dynamic fluctuations and more efficient modulation of ion–ligand interactions 37,38 . Therefore, the free 24C8 rings could provide a dynamic, readily exchangeable coordination environment for NPR-SPE. We performed variable–mixing–time 7 Li 2D exchange NMR experiments at 298 K to demonstrate the Li-ion transfer frequency in different coordination environments of NPR-SPE (Figures 4c–4e). At a short mixing time (5 ms), only diagonal auto-correlation peaks are observed, indicating negligible Li-ion exchange between the ring and PEG backbone at this timescale. When the mixing time is extended to 10 ms and 100 ms, clear off-diagonal cross-peaks emerge, whose coordinates ( δ 1 ≈ −0.25 ppm, δ 2 ≈ −0.76 ppm) unambiguously correspond to chemical exchange between 24C8–Li⁺ and PEG–Li⁺. This result provides direct evidence that in the NPR SPE, Li ions can undergo reversible and rapid migration between crown-ether coordination sites and polymer-chain coordination sites, and that this exchange occurs efficiently on the hundred-millisecond timescale 39,40 . For systematic comparison, the contour plots of 7 Li 2D exchange NMR spectra for the studied SPEs under identical conditions (298 K, mixing time from 5 ms to 100 ms) are shown in Figure 4f–4i. Compared to NPR-SPE, the weaker variation of the exchange signal is observed in PR-SPE, indicating that the immobilization of the ring via host–guest interactions significantly restricts the Li-ion transfer frequency. For CCE-SPE, exchange intensity remains basically unchanged as a result of its single-coordination model. The case in CCB-SPE is analogous to that in CCE-SPE because the chemical environments of the Li ion coordinated to the PEG side chain and to the PEG backbone are similar, making NMR spectra difficult to distinguish. In addition, the energy barriers of Li-ion transfer in the SPE calculated by MD simulations indicate that the Li ion hopping between different PEG segments in CCB-SPE requires overcoming a relatively high barrier of ~323 kJ mol −1 , primarily corresponding to the short R−O−R side chains (Figure S38). Whereas for NPR-SPE, the participation of 24C8 rings leads to a significantly reduced barrier of ~221 kJ mol −1 , further confirming the high Li-ion transfer frequency and corroborating the observation in 7 Li 2D exchange NMR spectra. Given these data, it can be determined that the improvement in Li-ion transport in NPR-SPE depends largely on the dynamicity of the 24C8 ring. Due to weak non-covalent interactions, the ring interpenetrating the backbone of the SPE could dynamically slide along the axle, with a low energy barrier, thereby showing high local polymer fluctuations. At this moment, as the “cable car” of Li ions, the ring with the favorable Li-ion coordination dynamically bridges adjacent coordination sites by its axial sliding along the backbone. This “Cableway”-like transport behavior not only facilitates the Li-ion transfer between coordination structures but also enables the fast relative Li-ion motion along chains, resulting in a high σ Li⁺ . Note that the interpenetrated ring has less effect on the dynamicity and mechanical properties of the main network in the case of NPR-SPE, highlighting the “cable car” role of the ring on Li-ion transport. Therefore, replacing the regular branching chains with freely sliding rings on the elaborated polymer backbone is an effective means to address the seesaw effect in SPEs. 2.3 ASSLMB with NPR-SPE Leveraging RT-LC enhancement, the Li symmetric cell using NPR-SPE exhibited remarkable cycling stability at 0.5 mA cm −2 , with a Li plating/stripping capacity of 0.5 mAh cm −2 , maintaining stable voltage fluctuations for over 7000 hours with a low overpotential (Figure 5a). Cells with CCB-SPE and CCN-SPE suffer from insufficient RT-LC, resulting in a short lifespan. Using NPR-SPE also allows the symmetric cell to operate under high rates at RT. The NPR-SPE cell sustained lower overpotentials than other cells across a rate range from 0.25 to 2.0 mA cm −2 (Figure 5b). Apart from the cycling lifespan, the NPR-SPE cell’s critical current density (CCD) was also much higher than that of the control samples and outperformed most related reports (Figure 5c, Figure S39, and Table S2). Consequently, when the rate increased to 1.0 mA cm −2 , the symmetric cell with NPR-SPE could cycle stably for 800 hours (Figure S40). Nano-computed tomography (nano-CT) analysis of the cycled cell at different cross-sectional positions confirmed the structural integrity of NPR-SPE (Figure 5d). It can also be observed that the Li cycling interface was stable, indicating the effective restriction of NPR-SPE on dendrite growth. The SEM images presented in Figure S41 corroborated the same result, a dendrite-free morphology attained by NPR-SPE after cycling at 0.5 mA cm −2 . Figure 5e shows the analysis of the atomic force microscopy combined with nano-infrared spectroscopy (AFM-nano IR) on the NPR-SPE. After cycling, the consistent intensity distribution of the characteristic absorption peak at 1250 cm −1 demonstrates the uniform chemical structure of NPR-SPE. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was employed for analyzing the solid-electrolyte interphase (SEI) of different symmetric cells (Figure 5f). At the interface, three main components can be identified: LiF 2 − , LiCO 3 − , and LiOC 2 H 4 − , which are attributed to the decomposition of anions and to fractured chains from the SPE 41,42 . After cycling, the thickness of the derived SEI in NPR-SPE is narrower than that of its counterparts, and the SEI of NPR-SPE shows limited growth at the Li metal interface. This result is closely related to the favorable mechanical properties and improved Li-ion transport of NPR-SPE, which effectively regulates the Li plating/stripping process to undergo a uniform and dendrite-free manner. Therefore, in NPR-SPE, a stable reaction interface could be established to significantly inhibit parasitic reactions and SEI hyperplasia, enabling fast and stable interfacial transport kinetics for Li ions (Figure S42). The pouch-type ASSLMBs, constructed by coupling NPR-SPE with Li metal (20 μm thickness) and LiFePO 4 (LFP) cathode, demonstrate impressive electrochemical properties (Figure 5g). The cross-sectional SEM of the LFP cathode is shown in Figure 5h, revealing that the pores were filled with SPE. In Figure 5i and Figure S43, the NPR-SPE cell was efficient at RT, delivering a stable 3.4 V discharge voltage and showing a slight decrease in cycling performance over 800 cycles at 1 C (the average output capacity is 135 mAh g −1 based on a 7.5 mg cm −2 cathode loading). Contrasting with the above, cells with CCN-SPE and CCB-SPE both showcased a fast capacity fading due to the unstable Li metal interface caused by insufficient Li-ion transport. Furthermore, we investigated the RT cycling performance of the NPR-SPE pouch cell at an extremely high rate of 10 C. Although polarization growth leads to a decrease in initial capacity output (Figure S44), 50% of the reversible capacity at 1 C (approximately 68.8 mAh g −1 ) could be retained at 10 C. Even after 2400 cycles, the NPR-SPE cell retained 85% of its initial capacity (Figure 5j). The NPR-SPE demonstrated here is compared with other state-of-the-art SPEs featuring regular crosslinking and covalent side-chain structures in Figure 5k and Table S3. One may recall that comparison can be complex, as electrode mass loading directly affects the actual current density at the same current rates. It can be seen that the cell using NPR-SPE has a remarkable improvement in the high-rate cycling at RT. Many of the SPEs listed in comparison below employ more complex architectures, including multiple monomer types, inorganic crosslinking centers, and irradiated plasticizers. Therefore, the result highlights that employing polyrotaxane techniques, either based on crown ethers or cyclodextrins, could impart a “Cableway”-like transport behavior to SPEs, deriving respectable Li-ion transport coupled with excellent mechanical properties to well application in ASSLMBs. CONCLUSIONS In this study, a prototype solid polymer electrolyte (SPE) based on a neutralized polyrotaxane (NPR) scaffold was successfully developed to decouple the relationship between the mechanical bond movement and Li-ion transport. The key structure of NPR-SPE lies in the strategic incorporation of freely sliding 24-crown-8 ether rings, which function as dynamic, non-covalent “side chains” threaded onto the main polymer backbone. A “Cableway” transport mechanism, derived by NPR-SPE, was identified, in which rings, acting as mobile “cable cars”, efficiently shuttle Li ions along the polymer axle. This dynamic motion, characterized by a low energy barrier, significantly enhances local polymer fluctuations, resulting in the improvement in Li-ion transfer between coordination structures and relative Li-ion transport along chains. Consequently, NRP-SPE achieved a room-temperature Li-ion conductivity of ~1.28 mS cm −1 , superior to control SPEs with covalent side chains or locked rings. When deployed in all-solid-state Li metal batteries (ASSLMBs) with pouch-type, NRP-SPE enabled improved electrochemical performance, including stable long-term cycling over 800 cycles at 1 C, high-rate capability (retaining 68.8 mAh g −1 at 10 C), and most critically, effective suppression of Li dendrite growth. The insight of this work is the paradigm shift from regular, covalent ion-transport pathways to dynamic, mechanically interlocked ones, paving the way for designing advanced SPEs. Declarations Acknowledgements Z. Liang acknowledges financial support from The Explorers Program of Shanghai (Basic Research Funding) under grant No. 25TS1400400, NSFC/China (22379093), Fundamental Research Funds for the Central Universities (25X010202131) and Henan Silane Technology Development Co., Ltd. under grant No. 22H010101201. X. Yan acknowledges the financial support through the NSFC/China (22471164 and 52421006), the NSF of Shanghai (22dz1207603), the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission (22SG11), and the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study (SN-ZJU-SIAS-006). X. Yue acknowledges the financial support of the NSFC/China (52573335). Z. Zhang acknowledges the financial support of the NSFC/China (22101175). Y. Liu acknowledges the financial support of the NSFC/China (223B2113). Z. Liang acknowledges technical support from Shanghai TANSUO Testing and Inspection Company for SEM and AFM-IR (Nano IR) characterizations. Author contributions Z. Shi and Y. Liu contributed equally to this work. X. Yue, Z. Zhang, X. Yan, and Z. Liang supervised this research and conceived the project. Z. Shi and X. Yue designed all experimental investigations and developed the process for fabricating the NPR-SPE. Z. Zhang, R. Bai, and Y. Liu synthesized the NPR and conducted the corresponding mechanical characterization. Z. Shi conducted all electrochemical tests. Q. Zeng, L. Ding, and S. Wei assisted with experiments. Z. Zhang carried out the rheological tests under the supervision of W. Yu. The manuscript was written by Z. Shi, X. Yue, Z. Zhang, Y. Liu, Z. Liang, and X. Yan, with contributions from all the co-authors. Additional information Supplementary information is available in the online version of the paper. 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Revealing solvent-assisted Li + transport in the solid electrolyte interphase operando. J. Am. Chem. Soc. 147 , 42701–42710 (2025). Lv, S. et al. A composite electrolyte with homogeneous heat and ion transfer for high-safety solid-state lithium batteries. Energy Environ. Sci. 18 , 10318–10327 (2025). Tolkkinen, K., Mankinen, O., Mailhiot, S. E. & Telkki, V.-V. Ultrafast T 1 –T 1ρ NMR for correlating different motional regimes of molecules. Anal. Chem. 96 , 16534–16542 (2024). Wang, X.-X. et al. An integrated solid-state lithium-oxygen battery with highly stable anionic covalent organic frameworks electrolyte. Chem 9 , 394–410 (2023). Zhao, Y. et al. Opening and constructing stable lithium-ion channels within polymer electrolytes. Angew. Chem. Int. Ed. 63 , e202404728 (2024). Liu, M. et al. Quantification of the Li-ion diffusion over an interface coating in all-solid-state batteries via NMR measurements. Nat. Commun. 12 , 5943 (2021). Chen, X. et al. Salt-free solid polymer electrolytes enabling inorganic-rich solid-electrolyte interphase for stable and cost-effective Li-metal batteries. Small 21 , 2500452 (2025). Zhao, L. et al. Anion Modulation: Enabling Highly Conductive Stable Polymer Electrolytes for Solid-State Li-Metal Batteries. Angew. Chem. Int. Ed. 63 , e202412280 (2024). Additional Declarations There is NO Competing Interest. Supplementary Files Supportinginformation260416.docx A Polyrotaxane-Based Solid Electrolyte with Cableway-Type Li-ion Transport Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9434833","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":631775246,"identity":"ce1822fc-1365-427a-bfac-4ccee9e28b1a","order_by":0,"name":"Zheng Liang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABEElEQVRIiWNgGAWjYBACPmYwdQCIGRsffGBgA3Ml8GlhQ2hhPmw4g4FNgrAWBrgWtjRhHqhq/FrYmZ89/PLnjpw5/xozZps/fHUGB5gP3uZhsMvD7TA2c2MZnmfGljPemD3ObWOTMDjAlmzNw5BcjMcvZtISEocTN9w4Y26c2wDSwmMmzcNwILEBpxb2b9ISBofrgVrMpC3+gLTwfyOghcdM8kPC4QSD821p0gxsYFvYCGkpk2Y4cNhwww1gIPe2sUnOPMxmbDnHIBmnFn7+49skf/w5LG9w/mDjgx9/jvHzHW9+eONNhR1OLSDAzAMiJRJA5DEgF0Qb4FEPBIw/wPYdAJE1+JWOglEwCkbBiAQAUzNSryUiy88AAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0001-9137-0338","institution":"Shanghai Jiao Tong University","correspondingAuthor":true,"prefix":"","firstName":"Zheng","middleName":"","lastName":"Liang","suffix":""},{"id":631775247,"identity":"8e652990-65d1-4307-b79b-c7f5186a879b","order_by":1,"name":"Zhangqin Shi","email":"","orcid":"","institution":"Shanghai Jiao Tong 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university","correspondingAuthor":false,"prefix":"","firstName":"Wei","middleName":"","lastName":"Yu","suffix":""},{"id":631775254,"identity":"899cabe6-09f5-4f93-b48a-3df360af7ef9","order_by":8,"name":"Shuang Wei","email":"","orcid":"","institution":"Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering Shanghai Jiao Tong University","correspondingAuthor":false,"prefix":"","firstName":"Shuang","middleName":"","lastName":"Wei","suffix":""},{"id":631775255,"identity":"9a735052-31ad-4fd8-9ae0-052c14c61836","order_by":9,"name":"Zhaoming Zhang","email":"","orcid":"","institution":"Shanghai Jiao Tong University","correspondingAuthor":false,"prefix":"","firstName":"Zhaoming","middleName":"","lastName":"Zhang","suffix":""},{"id":631775256,"identity":"0bf6250d-2a6b-44a9-a1a7-646c0d37d2de","order_by":10,"name":"Xuzhou Yan","email":"","orcid":"https://orcid.org/0000-0002-6114-5743","institution":"Shanghai Jiao Tong University","correspondingAuthor":false,"prefix":"","firstName":"Xuzhou","middleName":"","lastName":"Yan","suffix":""}],"badges":[],"createdAt":"2026-04-16 07:50:31","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9434833/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9434833/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108167376,"identity":"f69c950d-6584-4d33-9505-9eaaaaa79f50","added_by":"auto","created_at":"2026-04-30 06:12:01","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1668659,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAdvanced SPEs configured by MINs. \u003c/strong\u003eIllustration of the SPE with (\u003cstrong\u003ea\u003c/strong\u003e) the covalent crosslinking network (CCN), (\u003cstrong\u003eb\u003c/strong\u003e) the non-covalent crosslinking network (NCCN), and (\u003cstrong\u003ec\u003c/strong\u003e) the MIN. (\u003cstrong\u003ed\u003c/strong\u003e) Comparison of the CCN, NCCN, and MIN in terms of the mechanical properties, structural dynamicity, and structural reversibility. (\u003cstrong\u003ee\u003c/strong\u003e) The improvement of the MIN-based SPEs in Li-ion transport compared to SPEs with CCN and NCCN. (\u003cstrong\u003ef\u003c/strong\u003e) The potential Li-ion transport behavior associated with the ring coordination and movement in the polyrotaxane-based SPE. (\u003cstrong\u003eg\u003c/strong\u003e) The molecular structure of the 24C8-based polyrotaxane and the schematic of the studied polyrotaxane-based SPE network.\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-9434833/v1/04b0c7bdec9f7fb42f7af9b1.png"},{"id":108167381,"identity":"4ffcd21e-3cc5-427d-82a6-5509025c3e25","added_by":"auto","created_at":"2026-04-30 06:12:02","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":696501,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePreparation and structural analysis of SPEs. \u003c/strong\u003e(\u003cstrong\u003ea\u003c/strong\u003e) Key structure of NPR, PR, CCN, and CCB. (\u003cstrong\u003eb\u003c/strong\u003e) Partial \u003csup\u003e1\u003c/sup\u003eH NMR spectra (Acetone-d6, 400 MHz, 293 K) of 24-crown 8-ether (24C8), pseudorotaxane, and axle, where “c” and “uc” denote complexed and uncomplexed species, respectively. (\u003cstrong\u003ec\u003c/strong\u003e) Plot of the number of 24C8 units on the axle as a function of the feeding ratio of 24C8 to axle. (\u003cstrong\u003ed\u003c/strong\u003e) ATR-FTIR spectra of NPR and PR. (\u003cstrong\u003ee\u003c/strong\u003e) Toughness and breaking strain of the NPR-SPE, PR-SPE, CCN-SPE, and CCB-SPE.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-9434833/v1/6863607703dd9b1b8d21b53e.png"},{"id":108167378,"identity":"93539e29-dcb0-4945-9e6c-01864bd7c9ac","added_by":"auto","created_at":"2026-04-30 06:12:01","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1538459,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eLi-ion transport analysis in SPEs. \u003c/strong\u003e(\u003cstrong\u003ea\u003c/strong\u003e) Comparison of the ionic conductivity, Li-ion transference number, and Li-ion conductivity of NPR-SPE, PR-SPE, CCN-SPE, and CCB-SPE at RT. (\u003cstrong\u003eb\u003c/strong\u003e) The binding site of Li\u003csup\u003e+\u003c/sup\u003e∙∙∙24C8(R−O−R) and Li\u003csup\u003e+\u003c/sup\u003e∙∙∙PEG(R−O−R) in NPR-SPE. (\u003cstrong\u003ec\u003c/strong\u003e) MD snapshots of equilibrated configurations of NPR-SPE and CCN-SPE. (\u003cstrong\u003ed\u003c/strong\u003e) RDF profiles and coordination numbers for Li ions with oxygen donors in NPR-SPE. (\u003cstrong\u003ee\u003c/strong\u003e) MSD profiles of Li ions and TFSI\u003csup\u003e−\u003c/sup\u003e ions in NPR-SPE and CCN-SPE. (\u003cstrong\u003ef\u003c/strong\u003e) Master curves of NPR-SPE, PR-SPE, and CCB-SPE at a reference temperature of 30 °C. (\u003cstrong\u003eg\u003c/strong\u003e) DSC curves of CCB-SPE, CCN-SPE, PR-SPE, and NPR-SPE recorded by the second heating scan with a heating rate of 20 °C min\u003csup\u003e−1\u003c/sup\u003e.\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-9434833/v1/efc3b65633454cc9cbd0ef96.png"},{"id":108182798,"identity":"70a58c2e-2deb-46c3-9ce3-97217349d82f","added_by":"auto","created_at":"2026-04-30 08:59:33","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":411350,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eLi-ion transfer between coordination chains. \u003c/strong\u003e(\u003cstrong\u003ea\u003c/strong\u003e) Temperature-dependent ionic conductivities and the corresponding VTF fitting plots of different SPEs. (\u003cstrong\u003eb\u003c/strong\u003e) The spin-lattice relaxation times (\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e1\u003c/em\u003e\u003c/sub\u003e) of \u003csup\u003e7\u003c/sup\u003eLi in SPEs, and the insets are the solid-state \u003csup\u003e7\u003c/sup\u003eLi NMR spectra of 24C8 and PEG. \u003csup\u003e7\u003c/sup\u003eLi 2D exchange NMR of NPR-SPE (298 K) with mixing times of (\u003cstrong\u003ec\u003c/strong\u003e) 5, (\u003cstrong\u003ed\u003c/strong\u003e) 10, and (\u003cstrong\u003ee\u003c/strong\u003e) 100 ms. Contour images of the \u003csup\u003e7\u003c/sup\u003eLi 2D exchange NMR analysis for (\u003cstrong\u003ef\u003c/strong\u003e) NPR-SPE, (\u003cstrong\u003eg\u003c/strong\u003e) PR-SPE, (\u003cstrong\u003eh\u003c/strong\u003e) CCB-SPE, and (\u003cstrong\u003ei\u003c/strong\u003e) CCN-SPE under identical conditions.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-9434833/v1/6cec84e49fd004cc3edb6d2e.png"},{"id":108167380,"identity":"a3b4b590-d112-4dad-ad6c-082dcaa94f3b","added_by":"auto","created_at":"2026-04-30 06:12:01","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":2086114,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBattery performance at room temperature. \u003c/strong\u003e(\u003cstrong\u003ea\u003c/strong\u003e) The cycling stability of the Li symmetric cell using NPR-SPE, CCB-SPE, and CCN-SPE at 0.5 mA cm\u003csup\u003e−2\u003c/sup\u003e and 0.5 mAh cm\u003csup\u003e−2\u003c/sup\u003e. (\u003cstrong\u003eb\u003c/strong\u003e) Constant-current polarization curves of the symmetric cell at various current densities. (\u003cstrong\u003ec\u003c/strong\u003e) Comparison of the CCD performance in NPR-SPE versus prior reports. (\u003cstrong\u003ed\u003c/strong\u003e) Nano-CT images of NPR-SPE after cycling in simulated Li/SPE/Li cells. (\u003cstrong\u003ee\u003c/strong\u003e) AFM topography, nano-IR spectrum at 1250 cm\u003csup\u003e−1\u003c/sup\u003e, and FTIR spectrum (1000–1500 cm\u003csup\u003e−1\u003c/sup\u003e) of the NPR-SPE after cycling. (\u003cstrong\u003ef\u003c/strong\u003e) 3D TOF-SIMS images of the LiF\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e−\u003c/sup\u003e, LiCO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e−\u003c/sup\u003e, and LiOC\u003csub\u003e2\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e− \u003c/sup\u003eon the Li metal surface after cycling with NPR-SPE, CCB-SPE, and CCN-SPE. (\u003cstrong\u003eg\u003c/strong\u003e) Illustration of Li/NPR-SPE/LFP full cell. (\u003cstrong\u003eh\u003c/strong\u003e) The cross-sectional SEM image of the LFP cathode. (\u003cstrong\u003ei\u003c/strong\u003e) Long-term cycling performance of the LFP pouch cells at 1 C. (\u003cstrong\u003ej\u003c/strong\u003e) Cycling stability of the LFP pouch cell using NPR-SPE at 10 C. (\u003cstrong\u003ek\u003c/strong\u003e) Stability comparison of the NPR-SPE cell with other all-solid-state batteries reported in the literature.\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-9434833/v1/e58091c999f8952680d03c02.png"},{"id":108804101,"identity":"2c888d4d-dcd0-4406-a720-4f79905a3e6f","added_by":"auto","created_at":"2026-05-08 15:15:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":6284213,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9434833/v1/e3d26c1d-defe-44c8-9396-dd6dcaa605e9.pdf"},{"id":108167377,"identity":"d13ff92a-5bea-48a0-a6ec-fd16cdffa7ed","added_by":"auto","created_at":"2026-04-30 06:12:01","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":14395733,"visible":true,"origin":"","legend":"A Polyrotaxane-Based Solid Electrolyte with Cableway-Type Li-ion Transport","description":"","filename":"Supportinginformation260416.docx","url":"https://assets-eu.researchsquare.com/files/rs-9434833/v1/c381ce2dbe36f8b8bd8e665e.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"A Polyrotaxane-Based Solid Electrolyte with Cableway-Type Li-ion Transport","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eThe global transition towards sustainable energy has intensified the quest for next-generation electrochemical energy storage technologies\u003csup\u003e1,2\u003c/sup\u003e. All-solid-state lithium metal batteries (ASSLMBs) stand out as pivotal candidates, promising unparalleled safety and energy density\u003csup\u003e3,4\u003c/sup\u003e. Among solid-state electrolytes, solid polymer electrolytes (SPEs) offer distinct advantages, including superior mechanical flexibility and interfacial compatibility, which effectively mitigate issues like interfacial degradation and lithium dendrite growth prevalent in inorganic systems\u003csup\u003e5-7\u003c/sup\u003e. However, SPEs, such as polyethylene oxide (PEO), show a room-temperature Li-ion conductivity (RT-LC) lower than their liquid or ceramic counterparts\u003csup\u003e8,9\u003c/sup\u003e. More importantly, under the seesaw effect between ionic conductivity and mechanical properties in SPEs arising from the molecular motility, formidable challenges loom on the horizon for the real-world application of SPEs in achieving an expedient polymer matrix that provides both appreciably high RT-LC and structural integrity\u003csup\u003e10-14\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eThe Li-ion transport of SPEs relies on chain-segmental motion and inter-/intra-chain ion hopping between coordinating sites\u003csup\u003e15-17\u003c/sup\u003e. Therefore, local polymer fluctuations are paramount for facilitating Li-ion transfer between coordination structures and for the relative Li-ion motion along chains. Covalent (chemical) crosslinking is a conventional strategy to suppress the polymer crystallization and improve the mechanical properties of SPEs (Figure 1a). Yet, the cross-linkers act as pinning sites, severely restricting segmental fluctuations and, consequently, diminishing RT-LC\u003csup\u003e18-20\u003c/sup\u003e. To reintroduce dynamics, researchers have integrated non-covalent interactions (e.g., hydrogen and ionic bonds) into covalent networks\u003csup\u003e21-24\u003c/sup\u003e. However, the non-covalent (physical) crosslinking suffers from its weak structural reversibility and mechanical properties (Figure 1b). It is apparent that the routine combination of chemical and physical crosslinking typically sacrifices one aspect of performance for the other, making it challenging to overcome the seesaw effect in SPEs\u003csup\u003e25,26\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eThe impasse of SPEs has directed attention to mechanically interlocked networks (MINs) as a transformative design paradigm (Figure 1c). Since MINs uniquely integrate the robust, locked-in architecture of covalent networks with the dynamic, unlocked character of non-covalent systems at the molecular level\u003csup\u003e27-29\u003c/sup\u003e, they exhibit more pronounced intrinsic advantages than conventional covalent and non-covalent crosslinking networks (Figure 1d). This sophisticated unification offers a promising route to circumvent traditional trade-offs. Seo\u0026rsquo;s group designed a partially crosslinked polyrotaxane based on \u0026alpha;-cyclodextrin as a high-performance SPE, highlighting the potential application of MINs\u003csup\u003e30,31\u003c/sup\u003e. Our previous research proposed a molecular muscle SPE by crosslinking the [\u003cem\u003ec\u003c/em\u003e2] daisy chain with polyethylene glycol, demonstrating the favorable effect of interpenetrating dibenzo-24-crown-8 wheels on the movement of the Li-coordinated backbones\u003csup\u003e10\u003c/sup\u003e. In spite of the improvements to date being quite satisfactory, particularly with regard to the ionic conductivity (Figure 1e and Table S1), a critical knowledge gap persists: the precise mechanism of Li-ion transport within MINs, whether dominated by the motion of the ring-encouraged network or the Li ion-coordinated rings themselves, remains elusive (Figure 1f). This lack of fundamental understanding severely limits the rational design of high-performance MIN-structured SPEs.\u003c/p\u003e\n\u003cp\u003eIn this work, we aim to address this core question by unveiling a unique \u0026ldquo;Cableway\u0026rdquo; transport mechanism in a polyrotaxane-based MIN. We propose and demonstrate that the customized 24-crown 8-ether of [2]rotaxane with high local fluctuations can act as the \u0026ldquo;cable car\u0026rdquo; of Li ions to facilitate the Li-ion transport (Figure 1g). By strategically designing and comparing a series of SPEs with identical main networks but varying side-chain architectures, including a neutralized polyrotaxane (NPR), its host\u0026ndash;guest locked analogue (PR), a simple covalent network (CCN), and a covalent network with PEG side chains (CCB), we decouple the contributions of the mobile rings from the polymer network. Through a synergistic combination of rheology, two‑dimensional nuclear magnetic resonance (NMR), and molecular dynamics (MD) simulations, we demonstrate that the crown ether ring not only participates in Li-ion coordination but also enhances overall Li-ion transport by acting as a non-covalent branch, dramatically enhancing RT-LC without sacrificing mechanical properties. Therefore, the neutralized polyrotaxane-based SPE (NPR-SPE), serving as a prototype, exhibits Li-ion conductivity of ~1.28 mS cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e at 30 \u0026deg;C (Li-ion transference number of 0.88), outperforming its counterparts. When deployed in ASSLMBs at RT, NPR-SPE enables remarkable cycling stability (800 cycles), high-rate capability (68.8 mAh g\u003csup\u003e\u0026minus;1\u003c/sup\u003e at 10 C), and effective dendrite suppression.\u003c/p\u003e"},{"header":"2. RESULTS \u0026 DISCUSSION","content":"\u003cp\u003e\u003cstrong\u003e2.1. Structure design and characterization\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo better investigate the distinctive roles of movable 24-crown 8-ether (24C8) rings within polymer networks on Li-ion transport, we prepared four related samples with the same main crosslinking network but different side chains: MIN with polyrotaxane (PR), MIN with neutralized polyrotaxane (NPR), single covalent crosslinking network (CCN), and the CCN with PEG side chains (CCB) (Figure 2a). By leveraging host\u0026ndash;guest recognition of a small-molecule template\u003csup\u003e32\u003c/sup\u003e, we develop an efficient strategy to prepare a crown ether-based polyrotaxane. This strategy relies on a crucial molecular axle decorated with four secondary ammonium salt sites. Upon mixing with 24C8, a portion of the rings forms pseudorotaxanes by binding to these sites, as shown in the synthetic routes summarized in Supplementary Section S2\u0026nbsp;and Figure S1\u0026ndash;S19. The axle\u0026rsquo;s terminal alkene units react with thiol-functionalized 4-armed PEG via thiol\u0026ndash;ene click chemistry, introducing the polymer chains and forming the targeted PR that preserves host\u0026ndash;guest interactions and restricts ring slipping, as shown in Figure S20.\u003c/p\u003e\n\u003cp\u003eStrategic deprotonation via immersion in potassium tert-butoxide/DMF solution neutralizes the secondary ammonium centers, liberating 24C8 macrocycles for unrestricted axial motion along polymer chains to yield NPR. Two control samples were prepared based on axles without the 24C8 ring. The CCN was obtained after the thiol\u0026ndash;ene click chemistry and neutralization reaction (Figure S21). For CCB, short PEG side chains were introduced onto the secondary ammonium centers of the axle, followed by the same thiol\u0026ndash;ene click chemistry and neutralization steps (Figure S22\u0026ndash;S25). All networks share a similar crosslinking density (Figure S26).\u003c/p\u003e\n\u003cp\u003eTo verify the formation of pseudorotaxane precursors prior to network formation, \u003csup\u003e1\u003c/sup\u003eH NMR analysis was performed on mixtures of the molecular axle and 24C8 (Figure 2b). Significant chemical shift perturbations were observed upon mixing: protons adjacent to the secondary ammonium centers (H\u003csub\u003e3\u003c/sub\u003e and H\u003csub\u003e4\u003c/sub\u003e) exhibited downfield shifts, while resonances associated with 24C8 shifted upfield\u003csup\u003e33\u003c/sup\u003e. These characteristic shifts are consistent with established host\u0026ndash;guest recognition phenomena between 24C8 and secondary ammonium ions. Quantification of the threaded 24C8 was achieved by integrating the peak corresponding to the complexed macrocycle (H\u003csub\u003e5c\u003c/sub\u003e) and normalizing it against a characteristic, non-interfering peak on the axle. This analysis revealed that the stoichiometric ratio of 24C8 to axle critically influences the threading efficiency under the employed reaction conditions.\u003c/p\u003e\n\u003cp\u003eIncreasing the feed ratio increased the amount of captured 24C8. As shown in Figure 2c, the number of the 24C8 ring on the axle was near saturation when the feed ratio was 4:1. To construct a uniform ring distribution on the main network, the saturation ratio was employed for PR and NPR, introducing an average of three 24C8 macrocycles per axle molecule. Following deprotonation to generate NPR, Fourier-transform infrared (FTIR) spectroscopy confirmed the removal of PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e counterions (Figure 2d). The disappearance of characteristic PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e vibrational modes, specifically the P\u0026minus;F stretching peak at 842 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e and the F\u0026minus;P\u0026minus;F bending peak at 559 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e in the NPR spectrum, provides direct evidence for the successful neutralization of the secondary ammonium salts and subsequent dissociation of the anions from the polymer network. In the absence of host\u0026ndash;guest recognition, the ring\u0026rsquo;s motion on NPR is more flexible than in PR. Therefore, we speculate that favorable Li-ion transport behavior could occur in the NPR-based SPE.\u003c/p\u003e\n\u003cp\u003eThe SPE was fabricated by immersing the polymer network in LiTFSI/THF solution (1:4 w/w) for 24 hours, followed by heating at 60 \u0026deg;C for 12 h to completely remove residual solvent (Figure S27). NPR-SPE has a defect-free morphology with a uniform thickness of ~100 \u0026mu;m, in which the LiTFSI species were homogeneously distributed throughout the polymer, as evidenced by F and S elemental mapping (Figure S28). The scanning electron microscope (SEM) images of other samples are collected in Figure S29. The polymer\u0026rsquo;s structure remained stable after adding the lithium salt. As revealed by the strain\u0026ndash;stress profiles (Figure 2e and Figures S30), the polymer was soft after mixing with LiTFSI, which can be ascribed to the dynamic improvement by non-covalent interactions between Li\u003csup\u003e+\u003c/sup\u003e/TFSI\u003csup\u003e\u0026minus;\u003c/sup\u003e ions and the polar sites of the polymer. On the other hand, incorporating 24C8 increases SPE toughness, an effect correlated with the rotaxane\u0026rsquo;s dynamic sliding mechanism.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 Li-ion coordination and transport\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo determine the RT-LC (\u003cem\u003e\u0026sigma;\u003csub\u003eLi⁺\u003c/sub\u003e\u003c/em\u003e) as depicted in Figure 3a, multiply the total ionic conductivity by the measured Li-ion transference number (\u003cem\u003et\u003csub\u003eLi⁺\u003c/sub\u003e\u003c/em\u003e) of each SPE (Figure S31, S32). NPR-SPE incorporating freely sliding 24C8 rings exhibited a \u003cem\u003e\u0026sigma;\u003csub\u003eLi⁺\u003c/sub\u003e\u003c/em\u003e of ~1.28 mS cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, which is much higher than other SPEs. Although the main PEG network of SPEs also contains Li-coordinated sites, its relatively weak dynamics at RT are not conducive to ion transport compared to the side chains. Given the lack of Li-coordinated side chains, the low \u003cem\u003e\u0026sigma;\u003csub\u003eLi⁺\u003c/sub\u003e\u003c/em\u003e of CCN is understandable. By contrast, for SPEs using PR and CCB, their lower \u003cem\u003e\u0026sigma;\u003csub\u003eLi⁺\u003c/sub\u003e\u003c/em\u003e than that of NPR-SPE is of interest for investigating side-chain movement and also suggesting the possibility of favorable Li-ion transport mechanisms in NPR-SPE.\u003c/p\u003e\n\u003cp\u003eThe Li-ion coordination environment within SPEs was analyzed using density functional theory (DFT) and molecular dynamics (MD) simulations. As shown in Figure 3b and Figure S33, the binding energy (\u003cem\u003eE\u003csub\u003eb\u003c/sub\u003e\u003c/em\u003e) of the Li ion with the C\u0026minus;O\u0026minus;C side for the main PEG network and 24C8 ring is ~179.0 and ~221.8 kJ mol\u003csup\u003e\u0026minus;1\u003c/sup\u003e, respectively. The \u003csup\u003e7\u003c/sup\u003eLi static NMR spectra confirm the coexistence of two distinct Li species with different chemical environments in NPR-SPE (Figure S34). Radial distribution function (RDF) profiles revealed a prominent, sharp peak corresponding to Li⁺∙∙∙O(24C8) interactions, indicating closer and more frequent coordination than in Li⁺∙∙∙O(PEG) (Figures 3c and 3d). Consistently, the mean squared displacement (MSD) of the Li ion in NPR-SPE is higher than that in CCN-SPE, quantitatively confirming the enhanced Li-ion mobility conferred by the presence of 24C8 rings (Figure 3e). Due to the enhanced Li-ion coordination by rings and the restriction on the transport of large-sized anions, NPR-SPE shows the highest \u003cem\u003et\u003csub\u003eLi⁺\u003c/sub\u003e\u003c/em\u003e among the samples. These results indicate that the dynamic ring can not only participate in ion transport but may also construct a fast Li-ion transport channel.\u003c/p\u003e\n\u003cp\u003eBoth the skeleton and the ring can serve as ion transport sites in NPR-SPE. It is crucial to explore the impact of the ring on the dynamics of the main network to accurately identify its role in improving Li-ion transport. Master curves were obtained with a reference temperature of 30 \u0026deg;C through the time-temperature superposition (TTS) principle. All three samples (PR-SPE, CCB-SPE, and NPR-SPE) exhibited a typical elastic plateau across the measured frequency range, indicative of well-organized network structures (Figure 3f and Figure S35). Within the CCB-SPE network, the plateau modulus varied slightly among the samples, indicating that internal dissipation is primarily dominated by PEG chain friction. The modulus of PR-SPE is slightly higher than that of NPR-SPE, and its \u003cem\u003etan \u0026delta;\u003c/em\u003e curve exhibits a steeper slope, demonstrating the greater elasticity and a more pronounced viscoelastic transition of PR-SPE\u003csup\u003e34\u003c/sup\u003e. This result is likely due to the free 24C8 rings facilitating segmental motion.\u003c/p\u003e\n\u003cp\u003eGiven the similar cross-linking densities across all samples, the above observation suggests that the presence of freely movable 24C8 rings enhances the overall mobility of the polymer to some extent. The results of the glass transition temperatures (\u003cem\u003eT\u003csub\u003eg\u003c/sub\u003e\u003c/em\u003e) also confirm the \u0026ldquo;dynamic plasticization\u0026rdquo; effect of the 24C8 ring in NPR-SPE (Figure 3g). Differential scanning calorimetry (DSC) reveals a distinct \u003cem\u003eT\u003csub\u003eg\u003c/sub\u003e\u003c/em\u003e trend: NPR-SPE \u0026lt; PR-SPE \u0026lt; CCB-SPE \u0026lt; CCN-SPE. While the short side chains of CCB-SPE provide plasticization through localized segmental activation, their efficacy falls short of the dynamic sliding of 24C8 rings. However, compared to the previous SPE using MIN, which integrates the ring into the overall network, the improvement in mechanical properties and dynamics of the NPR-SPE is relatively weak (Figure S36). This phenomenon can be attributed to the hanging-ring structure depended on the non-covalent interaction, affecting the main network less than the ring covalently connected to the network. Combined with the results of the notable increase in \u003cem\u003e\u0026sigma;\u003csub\u003eLi⁺\u003c/sub\u003e\u003c/em\u003e and the lower energy barrier of the ring than that of the main crosslinking network in molecular motion, it is reasonable to infer that the key contribution to the RT-LC stems from the movement of the ring as the Li-ion carrier, rather than the movement of the main network.\u003c/p\u003e\n\u003cp\u003eTo probe the dynamic coordination environment of Li ions at the molecular scale and its correlation with macroscopic transport properties, we employed electrochemical impedance spectroscopy (EIS) and \u003csup\u003e7\u003c/sup\u003eLi solid-state nuclear magnetic resonance (NMR) technology. The activation energy (\u003cem\u003eE\u003csub\u003ea\u003c/sub\u003e\u003c/em\u003e) for ion transport was investigated using temperature-dependent EIS profiles\u003csup\u003e35,36\u003c/sup\u003e. Based on the Vogel\u0026ndash;Tammann\u0026ndash;Fulcher (VTF) fitting (Figure S37), NPR-SPE shows an \u003cem\u003eE\u003csub\u003ea\u003c/sub\u003e\u003c/em\u003e of 42.6 kJ mol\u003csup\u003e\u0026minus;\u003c/sup\u003e\u003csup\u003e1\u003c/sup\u003e, lower than that of other SPEs (Figure 4a), aligning well with the results of the high \u003cem\u003e\u0026sigma;\u003csub\u003eLi⁺\u003c/sub\u003e\u003c/em\u003e of NPR-SPE at RT. The \u003csup\u003e7\u003c/sup\u003eLi NMR spin-lattice relaxation times (\u003cem\u003eT\u003csub\u003e1\u003c/sub\u003e\u003c/em\u003e) of SPEs are shown in Figure 4b. The \u003cem\u003eT\u003csub\u003e1\u003c/sub\u003e\u003c/em\u003e value for NPR-SPE, PR-SPE, CCB-SPE, and CCN-SPE is 0.167, 0.269, 0.261, and 0.325 s, respectively. A shorter \u003cem\u003eT\u003csub\u003e1\u003c/sub\u003e\u003c/em\u003e generally indicates faster local dynamic fluctuations and more efficient modulation of ion\u0026ndash;ligand interactions\u003csup\u003e37,38\u003c/sup\u003e. Therefore, the free 24C8 rings could provide a dynamic, readily exchangeable coordination environment for NPR-SPE.\u003c/p\u003e\n\u003cp\u003eWe performed variable\u0026ndash;mixing\u0026ndash;time \u003csup\u003e7\u003c/sup\u003eLi 2D exchange NMR experiments at 298 K to demonstrate the Li-ion transfer frequency in different coordination environments of NPR-SPE (Figures 4c\u0026ndash;4e). At a short mixing time (5 ms), only diagonal auto-correlation peaks are observed, indicating negligible Li-ion exchange between the ring and PEG backbone at this timescale. When the mixing time is extended to 10 ms and 100 ms, clear off-diagonal cross-peaks emerge, whose coordinates (\u003cem\u003e\u0026delta;\u003csub\u003e1\u003c/sub\u003e\u003c/em\u003e \u0026asymp; \u0026minus;0.25 ppm, \u003cem\u003e\u0026delta;\u003csub\u003e2\u003c/sub\u003e\u003c/em\u003e \u0026asymp; \u0026minus;0.76 ppm) unambiguously correspond to chemical exchange between 24C8\u0026ndash;Li⁺ and PEG\u0026ndash;Li⁺. This result provides direct evidence that in the NPR SPE, Li ions can undergo reversible and rapid migration between crown-ether coordination sites and polymer-chain coordination sites, and that this exchange occurs efficiently on the hundred-millisecond timescale\u003csup\u003e39,40\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eFor systematic comparison, the contour plots of \u003csup\u003e7\u003c/sup\u003eLi 2D exchange NMR spectra for the studied SPEs under identical conditions (298 K, mixing time from 5 ms to 100 ms) are shown in Figure 4f\u0026ndash;4i. Compared to NPR-SPE, the weaker variation of the exchange signal is observed in PR-SPE, indicating that the immobilization of the ring via host\u0026ndash;guest interactions significantly restricts the Li-ion transfer frequency. For CCE-SPE, exchange intensity remains basically unchanged as a result of its single-coordination model. The case in CCB-SPE is analogous to that in CCE-SPE because the chemical environments of the Li ion coordinated to the PEG side chain and to the PEG backbone are similar, making NMR spectra difficult to distinguish. In addition, the energy barriers of Li-ion transfer in the SPE calculated by MD simulations indicate that the Li ion hopping between different PEG segments in CCB-SPE requires overcoming a relatively high barrier of ~323 kJ mol\u003csup\u003e\u0026minus;1\u003c/sup\u003e, primarily corresponding to the short R\u0026minus;O\u0026minus;R side chains (Figure S38). Whereas for NPR-SPE, the participation of 24C8 rings leads to a significantly reduced barrier of ~221 kJ mol\u003csup\u003e\u0026minus;1\u003c/sup\u003e, further confirming the high Li-ion transfer frequency and corroborating the observation in \u003csup\u003e7\u003c/sup\u003eLi 2D exchange NMR spectra.\u003c/p\u003e\n\u003cp\u003eGiven these data, it can be determined that the improvement in Li-ion transport in NPR-SPE depends largely on the dynamicity of the 24C8 ring. Due to weak non-covalent interactions, the ring interpenetrating the backbone of the SPE could dynamically slide along the axle, with a low energy barrier, thereby showing high local polymer fluctuations. At this moment, as the \u0026ldquo;cable car\u0026rdquo; of Li ions, the ring with the favorable Li-ion coordination dynamically bridges adjacent coordination sites by its axial sliding along the backbone. This \u0026ldquo;Cableway\u0026rdquo;-like transport behavior not only facilitates the Li-ion transfer between coordination structures but also enables the fast relative Li-ion motion along chains, resulting in a high \u003cem\u003e\u0026sigma;\u003csub\u003eLi⁺\u003c/sub\u003e\u003c/em\u003e. Note that the interpenetrated ring has less effect on the dynamicity and mechanical properties of the main network in the case of NPR-SPE, highlighting the \u0026ldquo;cable car\u0026rdquo; role of the ring on Li-ion transport. Therefore, replacing the regular branching chains with freely sliding rings on the elaborated polymer backbone is an effective means to address the seesaw effect in SPEs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3 ASSLMB with NPR-SPE\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLeveraging RT-LC enhancement, the Li symmetric cell using NPR-SPE exhibited remarkable cycling stability at 0.5 mA cm\u003csup\u003e\u0026minus;2\u003c/sup\u003e, with a Li plating/stripping capacity of 0.5 mAh cm\u003csup\u003e\u0026minus;2\u003c/sup\u003e, maintaining stable voltage fluctuations for over 7000 hours with a low overpotential (Figure 5a). Cells with CCB-SPE and CCN-SPE suffer from insufficient RT-LC, resulting in a short lifespan. Using NPR-SPE also allows the symmetric cell to operate under high rates at RT. The NPR-SPE cell sustained lower overpotentials than other cells across a rate range from 0.25 to 2.0 mA cm\u003csup\u003e\u0026minus;2\u0026nbsp;\u003c/sup\u003e(Figure 5b). Apart from the cycling lifespan, the NPR-SPE cell\u0026rsquo;s critical current density (CCD) was also much higher than that of the control samples and outperformed most related reports (Figure 5c, Figure S39, and Table S2). Consequently, when the rate increased to 1.0 mA cm\u003csup\u003e\u0026minus;2\u003c/sup\u003e, the symmetric cell with NPR-SPE could cycle stably for 800 hours (Figure S40).\u003c/p\u003e\n\u003cp\u003eNano-computed tomography (nano-CT) analysis of the cycled cell at different cross-sectional positions confirmed the structural integrity of NPR-SPE (Figure 5d). It can also be observed that the Li cycling interface was stable, indicating the effective restriction of NPR-SPE on dendrite growth. The SEM images presented in Figure S41 corroborated the same result, a dendrite-free morphology attained by NPR-SPE after cycling at 0.5 mA cm\u003csup\u003e\u0026minus;2\u003c/sup\u003e. Figure 5e shows the analysis of the atomic force microscopy combined with nano-infrared spectroscopy (AFM-nano IR) on the NPR-SPE. After cycling, the consistent intensity distribution of the characteristic absorption peak at 1250 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e demonstrates the uniform chemical structure of NPR-SPE.\u003c/p\u003e\n\u003cp\u003eTime-of-flight secondary ion mass spectrometry (TOF-SIMS) was employed for analyzing the solid-electrolyte interphase (SEI) of different symmetric cells (Figure 5f). At the interface, three main components can be identified: LiF\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, LiCO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, and LiOC\u003csub\u003e2\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, which are attributed to the decomposition of anions and to fractured chains from the SPE\u003csup\u003e41,42\u003c/sup\u003e. After cycling, the thickness of the derived SEI in NPR-SPE is narrower than that of its counterparts, and the SEI of NPR-SPE shows limited growth at the Li metal interface. This result is closely related to the favorable mechanical properties and improved Li-ion transport of NPR-SPE, which effectively regulates the Li plating/stripping process to undergo a uniform and dendrite-free manner. Therefore, in NPR-SPE, a stable reaction interface could be established to significantly inhibit parasitic reactions and SEI hyperplasia, enabling fast and stable interfacial transport kinetics for Li ions (Figure S42).\u003c/p\u003e\n\u003cp\u003eThe pouch-type ASSLMBs, constructed by coupling NPR-SPE with Li metal (20 \u0026mu;m thickness) and LiFePO\u003csub\u003e4\u003c/sub\u003e (LFP) cathode, demonstrate impressive electrochemical properties (Figure 5g). The cross-sectional SEM of the LFP cathode is shown in Figure 5h, revealing that the pores were filled with SPE. In Figure 5i and Figure S43, the NPR-SPE cell was efficient at RT, delivering a stable 3.4 V discharge voltage and showing a slight decrease in cycling performance over 800 cycles at 1 C (the average output capacity is 135 mAh g\u003csup\u003e\u0026minus;1\u003c/sup\u003e based on a 7.5 mg cm\u003csup\u003e\u0026minus;2\u003c/sup\u003e cathode loading). Contrasting with the above, cells with CCN-SPE and CCB-SPE both showcased a fast capacity fading due to the unstable Li metal interface caused by insufficient Li-ion transport.\u003c/p\u003e\n\u003cp\u003eFurthermore, we investigated the RT cycling performance of the NPR-SPE pouch cell at an extremely high rate of 10 C. Although polarization growth leads to a decrease in initial capacity output (Figure S44), 50% of the reversible capacity at 1 C (approximately 68.8 mAh g\u003csup\u003e\u0026minus;1\u003c/sup\u003e) could be retained at 10 C. Even after 2400 cycles, the NPR-SPE cell retained 85% of its initial capacity (Figure 5j). The NPR-SPE demonstrated here is compared with other state-of-the-art SPEs featuring regular crosslinking and covalent side-chain structures in Figure 5k and Table S3. One may recall that comparison can be complex, as electrode mass loading directly affects the actual current density at the same current rates. It can be seen that the cell using NPR-SPE has a remarkable improvement in the high-rate cycling at RT. Many of the SPEs listed in comparison below employ more complex architectures, including multiple monomer types, inorganic crosslinking centers, and irradiated plasticizers. Therefore, the result highlights that employing polyrotaxane techniques, either based on crown ethers or cyclodextrins, could impart a \u0026ldquo;Cableway\u0026rdquo;-like transport behavior to SPEs, deriving respectable Li-ion transport coupled with excellent mechanical properties to well application in ASSLMBs.\u003c/p\u003e"},{"header":"CONCLUSIONS","content":"\u003cp\u003eIn this study, a prototype solid polymer electrolyte (SPE) based on a neutralized polyrotaxane (NPR) scaffold was successfully developed to decouple the relationship between the mechanical bond movement and Li-ion transport. The key structure of NPR-SPE lies in the strategic incorporation of freely sliding 24-crown-8 ether rings, which function as dynamic, non-covalent \u0026ldquo;side chains\u0026rdquo; threaded onto the main polymer backbone. A \u0026ldquo;Cableway\u0026rdquo; transport mechanism, derived by NPR-SPE, was identified, in which rings, acting as mobile \u0026ldquo;cable cars\u0026rdquo;, efficiently shuttle Li ions along the polymer axle. This dynamic motion, characterized by a low energy barrier, significantly enhances local polymer fluctuations, resulting in the improvement in Li-ion transfer between coordination structures and relative Li-ion transport along chains. Consequently, NRP-SPE achieved a room-temperature Li-ion conductivity of ~1.28 mS cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, superior to control SPEs with covalent side chains or locked rings. When deployed in all-solid-state Li metal batteries (ASSLMBs) with pouch-type, NRP-SPE enabled improved electrochemical performance, including stable long-term cycling over 800 cycles at 1 C, high-rate capability (retaining 68.8 mAh g\u003csup\u003e\u0026minus;1\u003c/sup\u003e at 10 C), and most critically, effective suppression of Li dendrite growth. The insight of this work is the paradigm shift from regular, covalent ion-transport pathways to dynamic, mechanically interlocked ones, paving the way for designing advanced SPEs.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eZ. Liang acknowledges financial support from The Explorers Program of Shanghai (Basic Research Funding) under grant No. 25TS1400400, NSFC/China (22379093), Fundamental Research Funds for the Central Universities (25X010202131) and Henan Silane Technology Development Co., Ltd. under grant No. 22H010101201. X. Yan acknowledges the financial support through the NSFC/China (22471164 and 52421006), the NSF of Shanghai (22dz1207603), the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission (22SG11), and the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study (SN-ZJU-SIAS-006). X. Yue acknowledges the financial support of the NSFC/China (52573335). Z. Zhang acknowledges the financial support of the NSFC/China (22101175). Y. Liu acknowledges the financial support of the NSFC/China (223B2113). Z. Liang acknowledges technical support from Shanghai TANSUO Testing and Inspection Company for SEM and AFM-IR (Nano IR) characterizations.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eZ. Shi and Y. Liu contributed equally to this work. X. Yue, Z. Zhang, X. Yan, and Z. Liang supervised this research and conceived the project. Z. Shi and X. Yue designed all experimental investigations and developed the process for fabricating the NPR-SPE. Z. Zhang, R. Bai, and Y. Liu synthesized the NPR and conducted the corresponding mechanical characterization. Z. Shi conducted all electrochemical tests. Q. Zeng, L. Ding, and S. Wei assisted with experiments. Z. Zhang carried out the rheological tests under the supervision of W. Yu. The manuscript was written by Z. Shi, X. Yue, Z. Zhang, Y. Liu, Z. Liang, and X. Yan, with contributions from all the co-authors.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSupplementary information is available in the online version of the paper. Reprints and permissions information is available online at www.nature.com/reprints. Correspondence and requests for materials should be addressed to Z. Liang.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting financial interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing financial interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLin, D., Liu, Y. \u0026amp; Cui, Y. Reviving the lithium metal anode for high-energy batteries. \u003cem\u003eNat. Nanotechnol.\u003c/em\u003e \u003cstrong\u003e12\u003c/strong\u003e, 194\u0026ndash;206 (2017).\u003c/li\u003e\n\u003cli\u003eNikodimos, Y. et al. 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Ed.\u003c/em\u003e \u003cstrong\u003e63\u003c/strong\u003e, e202412280 (2024).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"solid polymer electrolyte, polyrotaxane, Li-ion transport, molecular motility, solid-state battery","lastPublishedDoi":"10.21203/rs.3.rs-9434833/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9434833/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSolid polymer electrolytes (SPEs) are promising candidates for all-solid-state lithium batteries, yet their practical application is hindered by the low room-temperature Li-ion conductivity. Herein, we propose a “Cableway”-like transport for the high-Li-conductive SPE by substituting the regular Li-coordination side chains of the main network with flexible rotaxane structures. With reduced constraints imposed by covalent crosslinking, the 24-crown 8-ether, as the “cable car” of Li ions, could dynamically slide along the backbone of the neutralized polyrotaxane-based SPE (NPR-SPE). This promotes the Li-ion transfer between the branches or rings while maintaining mechanical properties and dissipating local energy. The NPR-SPE exhibits a Li-ion conductivity of ~1.28 mS cm\u003csup\u003e−1\u003c/sup\u003e at 30 °C, five times higher than the SPE configured by the polyethylene glycol branches, although they share a similar main cross-linking network. The LiFePO\u003csub\u003e4 \u003c/sub\u003ecell with NPR-SPE attains a reversible capacity of 68.8 mAh g\u003csup\u003e−1\u003c/sup\u003e at 10 C and demonstrates stable 2400 cycles with efficient dendrite restriction.\u003c/p\u003e","manuscriptTitle":"A Polyrotaxane-Based Solid Electrolyte with Cableway-Type Li-ion Transport","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-30 06:11:57","doi":"10.21203/rs.3.rs-9434833/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-chemistry","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"nchem","sideBox":"Learn more about [Nature Chemistry](http://www.nature.com/nchem/)","snPcode":"","submissionUrl":"","title":"Nature Chemistry","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Research","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"0aceb87b-ed4b-4747-8878-afc2451a4607","owner":[],"postedDate":"April 30th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"This content is not available.","date":"2026-05-13T08:36:05+00:00","index":1,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2026-05-09T09:35:05+00:00","index":4,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2026-05-04T12:36:04+00:00","index":3,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2026-05-01T08:23:49+00:00","index":2,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2026-04-30T19:54:45+00:00","index":1,"fulltext":"This content is not available."},{"type":"reviewersInvited","content":"8","date":"2026-04-29T12:40:46+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":67246397,"name":"Physical sciences/Chemistry/Energy"},{"id":67246398,"name":"Physical sciences/Chemistry/Polymer chemistry/Supramolecular polymers"}],"tags":[],"updatedAt":"2026-04-30T06:11:57+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-30 06:11:57","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9434833","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9434833","identity":"rs-9434833","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}