Elastic interfacial layer enabled the high-temperature performance of lithium-ion batteries via utilization of synthetic fluorosulfate additive

Abstract Ensuring interfacial stability of Si-containing anodes and Ni-rich cathodes is the key to achieving high-energy lithium-ion cells. Herein, we present 4-(allyloxy)phenyl fluorosulfate (APFS), a multi-functional electrolyte additive that forms a mechanical strain-adaptive solid electrolyte interphase (SEI) composed of LiF and polymeric species, and a thermally stable cathode–electrolyte interface containing S–O and S–F species. Radical copolymerization of vinylene carbonate (VC) with APFS via electrochemical initiation creates a spatially deformable polymeric SEI on the Si/C-graphite (SiG-C) anode with large volume changes during cycling. Here we show that APFS-promoted interfacial layers reduce Ni dissolution and deposition and that APFS deactivates Lewis acidic PF5, inhibiting the hydrolysis that produces unwanted HF. These results show that the combined use of VC and APFS allows capacity retention of 72.5% with a high capacity of 143.5 mAh g− 1 after 300 cycles at 45°C.