Role of sintering temperature on microstructure, ionic conductivity and green electricity generation of hydroelectric cell

Role of sintering temperature on microstructure, ionic conductivity and green electricity generation of hydroelectric cell | 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 Research Article Role of sintering temperature on microstructure, ionic conductivity and green electricity generation of hydroelectric cell Neelam Singh, Seema Dhankhar, Aniket Tayal, Vivek Verma This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7000548/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In recent years, green energy sources have been attracted considerable great attention, since these sources are able to produce low-cost, clean, efficient and sustainable energy. A hydroelectric cell generates electrical energy in milliwatts range using only few drops of water. In recent years, scientific and technological research have been done to increase its efficiency followed by explanation of basic working principle. This paper presents comprehensive and significant research conducted, current state of research and development, on-going challenges. Moreover, fabrication of hydroelectric cell with good efficiency durability is still a challenging task. Role of materials, microstructure, sample size in ionic conductivity and electricity generation by hydroelectric cells have been discussed in details. Hydroelectric Cell Water Dissociation Porous Oxide Green Energy Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Electrical energy is one of the fundamental requirements in our lives. Population is increasing day by day worldwide that causes a more demand for electrical energy. At the present time with the escalating global energy crisis and environmental concern, we are running with scarcity of energy, it is call for all of us to pay attention toward diminishing natural resources of energy [1, 2]. Word is facing problem of increasing demand of energy and decreasing conventional energy sources such as natural gas, oil, coal etc. Conventional energy sources can cause several types of pollutions like air pollution, green house gasses and acid rain which causing severe effect on human health [3, 4]. The need of the hour is to invent and use alternative sustainable green energy sources. The extraction and utilization of non-conventional energy will not only help in meeting energy demands but also help in their development. Since non-conventional energy sources provide environment-friendly, non-polluting energy, they help keep the atmosphere and environment clean and safe. As we know that solar energy is clean, pollution free, natural and one of the majorly explored source of renewable energy [5, 6]. From many years scientists has been working on this area to discover new methods to replace conventional sources of energy with renewable sources of energy. It provides a reliable and effective way for solving the problem of energy crises and environmental protection. Solar cell is one of them and majorly used to produce electrical energy. But there are some limitations of solar cells due to which we have to look for alternate source of green energy [7, 8]. The initial cost of purchasing a solar system is fairly high. This includes paying for solar panels, inverter and batteries. Solar panels are weather dependent. Few cloudy, rainy days can have a noticeable effect on the energy system. Solar energy has to be used right away, or it can be stored in large batteries. These batteries, used in off the grid solar systems, can be charged during the day so that the energy is used at night. So, we can say that solar energy storage is expensive. Recently Hydroelectric Cell device has been invented as a unique, revolutionary and path breaking invention to generate green electricity without using any electrolyte/light/electricity [9, 10]. It is based on non-photocatalytic technique to dissociate water molecules into (H 3 O + and OH − ) ions on the surface of oxide materials without supplying any external energy like electrolyte/light/temperature, generates green electricity [11]. Energy generated by HEC is comparable to solar cells and fuel cells power output at low cost. A very little capital-intensive industry can produce it. The adsorption of water on oxide surface can be in different manner. First, well-ordered ionic single-crystal samples are often nonreactive for H 2 O dissociation. It may be due to that the dissociation of water on the surface is by reaction at the defect sites and facet edges in the oxide polycrystalline samples, and defect sites are very less on the single crystals. The influence of defect lattice sites and oxygen deficit surfaces are important for dissociation of water. The second distinctive feature of H 2 O adsorption is the formation of relatively strong chemisorption bonds on some ionic surfaces, so that molecular adsorbed H 2 O can be stable even at room temperature [12, 13]. Water adsorption at metal-oxide surfaces is governed by a subtle balance between water-water hydrogen bonding and water-metal oxide interactions, which together determine the stability of the water structures formed. The energy produced by HEC can be utilized in domestic residential applications in decentralized mode at low cost because conventional usage of electrical energy is associated with huge expense of electrical transmission and distribution. It can also supply the electrical needs of the household and in automotive engine as a clean energy source. Production and usage of such cells is not capital intensive unlike electrical power generation systems. Technological improvements could make invented cell as an electrical energy source imbibed with an economic reality in bigger scale. Although a considerable amount of research is required to generate HEC cell panels and their maintenance for large scale usage in the form of a power station. The future of power generation will certainly include hydroelectric cell systems. In this work, lithium doped SnO 2 based hydroelectric cells were synthesized by solid state sintering method and investigation was made on the role of microstructure, ionic conduction and electricity generation. 2. Experimental 2.1. Synthesis method The 15 mol % Lithium doped SnO 2 samples were synthesized by solid state sintering method. Lithium carbonate (LiCO 3 ) and stannic oxide (SnO 2 ) were used as precursors. Stoichiometric molar ratio of these precursors was taken, mixed and ground for 6-7 hours in acetone medium to get uniform mixing of powders. The obtained powder samples were pre-sintered at 500 o C for 5 h followed by grinding for 2 hours. Thereafter, pre-sintered powder samples were pelletized into 2-inch diameter circular pellets then final sintering was carried out at 500, 600, 700, 800 and 900 o C for 5 hours to obtain the required mechanical strength of all samples to use in cell. Subsequently, one face of these sintered 2-inch diameter circular pellets was attached with zinc plate (acts as anode) and other face is pasted with silver (acts as cathode) as shown in Figure 1. The structural characterization of samples was carried out by the X-ray diffraction (XRD, Bruker D4, step size = 0.02º) technique using Cu Ka radiation (wavelength l = 1.5406 Å) and FTIR (4000–400 cm -1 , Perkin Elmer, UK). A field emission scanning electron microscope (JEOL/JSM-6610LV) was used to observe the microstructure details of the samples. Dielectric studies were performed to investigate ionic dissociation of water and its conduction in cell using impedance analyzer E4900A. Current and voltage generated by each hydroelectric cell was measured by digital multi meter (DMM). 2.2 Structural analysis All the samples were characterized by X-ray diffraction (XRD) method using Cu-Ka radiation (λ= 1.5406 Ǻ) at room temperature in the 2q range of 20-80 0 to analyse the phase formation. Figure 2 shows the typical XRD pattern of 15 mol % Lithium doped SnO 2 samples sintered at 500, 600, 700, 800 and 900 0 C. All the samples show good crystallization, with well-defined diffraction patterns corresponding to planes (110), (101), (200), (111), (211), (220) (002), (310), (112), (301), (202) and (321) between 2q range of 20-80 0 . Obtained structure of the prepared samples is exhibiting tetragonal rutile structure as confirmed from JCPDS file (JCPDS 41-1445) [14]. There is no extra peak observed except SnO 2 tetragonal rutile structure which indicates complete doping of lithium. Detailed and precise analysis of structural parameters of polycrystalline SnO 2 samples was conducted by Rietveld refinement using FullProf software. Lattice parameters were calculated by refining XRD data of all samples. Tetragonal structure with space group of P42/mnm was considered for Rietveld refinement of pristine and doped SnO 2 samples. Figure 2 clearly shows that observed and calculated patterns are in good agreement. The quality of Rietveld refinement was ensured by profile factor (Rp), weight difference measured and calculated values (Rwp), expected profile parameters (Rexp) and goodness of the fit indicator ( x 2 ). It can be observed from table 1 that there are no significant changes in lattice parameters of samples with sintering temperature. Table1. Rietveld refined lattice parameters and estimated reliability factors for the 15 mol% Li-doped SnO 2 samples sintered at different temperature Sample sintering temperature Phase/crystal structure Cell (Å) R-factor Rp Rwp c 2 500 ̊ C P42/mnm Tetragonal a = b = 4.7554 c = 3.1838 V = 71.9989 (Å 3 ) 7.49 9.51 3.41 600 ̊ C P42/mnm Tetragonal a = b = 4.7396 c = 3.1766 V = 71.3599 (Å 3 ) 7.37 9.26 2.81 700 ̊ C P42/mnm Tetragonal a = b = 4.7449 c = 3.1865 V = 71.7416 (Å 3 ) 4.79 6.23 1.31 800 ̊ C P42/mnm Tetragonal a = b = 4.7420 c = 3.1868 V = 71.6607 (Å 3 ) 5.70 7.15 1.88 900 ̊ C P42/mnm Tetragonal a = b = 4.7416 c = 3.1886 V = 71.6879 (Å 3 ) 6.22 7.89 2.00 2.3 Morphological studies The surface morphology of Li doped SnO 2 samples have been recognized at 100.00 K X magnification using FESEM. Figure 3 depicts the FESEM micrographs of prepared samples sintered at 500 ̊C , 600 ̊C, 700 ̊C, 800 ̊C and 900 ̊C. To evaluate the grain size of these samples, a histogram plots were obtained using image j software and the average grain size was evaluated to be around 20-25 nm. Average sampling was taken around 100 to estimate the distribution of grains. Morphology of SnO 2 Samples was significantly affected by the sintering temperatures. Figure 3 reveal that sample sintered at 500 ̊C exhibits a flakes-like structure and average grain growth around 25 nm. It also can be notice that distribution of grain is symmetrical. Samples sintered at 500 ̊C , 600 ̊C, 700 ̊C and 800 ̊C have nano-sized grain distribution with porosity, while, sample sintered at 900 ̊C has drastic change in microstructure. 2.4 Hydroelectric properties The working principle of hydroelectric cell is adsorption of water molecule in the oxide samples and its splitting into (OH - , H 3 O + ) ions and their conduction towards electrodes. As H 2 O molecules interact to oxide surface, immediately it split into ions (H 3 O + , OH - ) due to the defect lattice sites and oxygen deficit surfaces [15]. The dissociation of H 2 O molecule is mainly dependent on the electronegativity, number of unsaturated metal cations and metal oxide surface defects. Motion of dissociated H 3 O + ions through proton hopping while migration of OH − ions takes place through interconnected defective crystallite boundaries as a result output electrical current is generated. Also, dissociated H 3 O + ions produce localized electric field as they trapped within mesopores of oxide sample which leads to further instant dissociation of physisorbed water molecules spontaneously as represented by eq. 1. The hydroxide ions migrate towards the Zn electrode where zinc gets oxidized to Zn(OH) 2 (eq. 2) while H 3 O + ions towards the Ag electrode where they get reduced with evolution of H 2 gas (eq. 3) by capturing electrons from the Zn anode. This motion of ions towards their corresponding electrodes generates 0.95 V in the hydroelectric cell. At SnO 2 surface: 4H 2 O → 2H 3 O + + 2OH - (eq. 1) At anode: Zn + 2OH - → Zn(OH) 2 + 2e - (eq. 2) At cathode: 2e - + 2H 3 O + → 2H 2 O + H 2 (eq. 3) From the above reactions we can observed that the voltage generated between the electrodes is E cell = 0.22 + 0.76 = 0.98 V. To investigate the power production properties of SnO 2 cell, we have taken the observations of current for all prepared samples for 2 hour after spray the deionized water on samples. We repeated measurement in same sample as well in different sets of samples to observe the consistency/reproducibility of results. 15 % Li doped SnO 2 based hydroelectric cell, sintered at 500 ̊ C delivers maximum current ~65 mA. While, a decay is observed in the short-circuit current for all samples. Decrease in current with time may be attributed to oxidation of zinc electrode and concentration loss [16]. It is interesting to note that sample sintered at 600 ̊C exhibiting more stable current response. 3.5 DC Conductivity measurements To confirm the dissociation of water molecule and their conduction in the oxide medium was further confirm by I-V response of all the samples in dry and wet state at the room temperature. First current versus voltage response were recorded at dried samples (samples were placed at 100 ̊C for 1 h in oven) then at wet state (dip in deionized water for 1 min). It can be observed that all samples are showing almost ten times enhanced conductivity in wet state as shown in Figure 5. It concludes that water dissociation occurs in oxides and ions contribute in conductivity. In metal oxides, the absorbed water molecules on the surface and grain boundary are considered to be valuable probable path for proton transport at low temperature because of the high hydration properties of metal oxide compounds [17]. 3.6 Dielectric Properties Dielectric properties have been utilized to further investigate the role of microstructural properties on the water dissociation and ionic diffusion abilities of synthesized samples. Dielectric properties of samples were investigated in dry (without water) as well as wet (with water) state at the room temperature in the frequency range of 100 Hz to 1MHz by using impedance analyzer E4900A. Dielectric response of all samples has been shown in Figure 6. At lower frequency region dielectric response of wet samples is higher by magnitude of 10 which is due to ionic conduction of dissociate water molecules while in higher frequency range both have almost same constant dielectric values. So, the water molecules dissociation is established with these high dielectric values in wet samples [18]. Conclusion 15 mol % Lithium doped SnO 2 samples sintered at 500, 600, 700, 800 and 900 0 C were synthesized by solid state sintering method. Phase formation of all the samples has been confirmed by XRD. The lattice parameters were calculated by using Rietveld refinement technique. Surface morphology was depicted by using FESEM images and exhibits increase in grain size with sintering temperature. In all the synthesized hydroelectric cells, current and voltage generation have been investigated in detail. Maximum sustainable current was achieved for sample sintered at 500 0 C. These results motivate and open an opportunity to further investigate more sustainable and high-power hydroelectric cells in view of commercial applications. Discussion Acknowledgement The authors extend their gratitude to the Principal, Hindu College, University of Delhi for giving continual inspiration and drive to complete this effort. References Energy Statistics Pocketbook, Department of Economic and Social Affairs Statistics Division, United Nations 2024. Renewable Energy Statistics 2023-24, Government of India, www.mnre.gov.in. Saliha Saher, Sam Johnston, Ratu Esther-Kelvin, Jennifer M. Pringle, Douglas R. Mac Farlane & Karolina Matuszek, Trimodal thermal energy storage material for renewable energy applications. Nature 636, 622–626 (2024). https://doi.org/10.1038/s41586-024-08214-1. Wei Weng, Boming Jiang, Zhen Wang, Wei Xiao, In situ electrochemical conversion of CO 2 in molten salts to advanced energy materials with reduced carbon emissions, Sci. Adv. 2020; 6 : eaay9278. DOI: 10.1126/sciadv.aay9278. Mukilan P, Balasubramanian M, Jan Petrov, Jan Sobotík, Narayanamoorthi R, Sustainable tiles for renewable energy harvesting using integrated solar PV thermoelectric generator and piezoelectric technologies, Results in Engineering 26( 2025) 105478, https://doi.org/10.1016/j.rineng.2025.105478. Mehmet Gursoy, Ibrahim Dincer, A novel solar energy-based hydrogen generator integrated with battery storage, Energy, 330 (2025) 136824. https://doi.org/10.1016/j.energy.2025.136824. Markus Reusch, Martin Bivour, Martin Hermle, Stefan W. Glunz, Fill Factor Limitation of Silicon Heterojunction Solar Cells by Junction Recombination, Energy Procedia, 38 (2013) 297-304, https://doi.org/10.1016/j.egypro.2013.07.281. Ryo Fukasawa, Toru Asahi, Takuya Taniguchi, Effectiveness and limitation of the performance prediction of perovskite solar cells by process informatics, Energy Advances 3, Issue 4 (2024) 812-820, https://doi.org/10.1039/d3ya00617d. Ravinder Kumar Kotnala, Jyoti Shah, Green hydroelectrical energy source based on water dissociation by nanoporous ferrite, Int. J. Energy Res. 2016; 40:1652–1661, https://doi.org/10.1002/er.3545. Pranati Kharbanda, Tushar Madaan, Isha Sharma, Shruti Vashishtha, Parveen Kumar, Arti Chauhan, Sumit Mittal, Jarnail S. Bangruwa, Vivek Verma, Ferrites: magnetic materials as an alternate source of green electrical energy, 5 Issue 1 (2019)e01151, https://doi.org/10.1016/j.heliyon.2019.e01151. Jyoti Shah, Shipra Jain, Abha Shukla , Rekha Gupta, Ravinder Kumar Kotnala, A facile non-photocatalytic technique for hydrogen gas production by hydroelectric cell, Int. J. Hydrogen Energy 42 (2017) 30584-30590. https://doi.org/10.1016/j.ijhydene.2017.10.105. Udayakumar, A., Dhandapani, P., Ramasamy, S. et al. Recent developments in noble metal–based hybrid electrocatalysts for overall water splitting. Ionics 30, 61–84 (2024). https://doi.org/10.1007/s11581-023-05269-4 Dhongde, V., Velpandian, M. & Basu, S. Exploring the impact of structuralmodification of double perovskite composite cathode material on oxygen reduction reaction in intermediate temperature solid oxide fuel cell. Ionics 30, 8175–8190 (2024). https://doi.org/10.1007/s11581-024-05847-0 Parveen Kumar, Neelam Singh, Pradumn Kumar, Vivek Verma, Nanocomposite based hydroelectric cells: Working principle and production of green electrical energy, Inorg. Chem. Commun. 141 (2022) 109515, https://doi.org/10.1016/j.inoche.2022.109515. Rakesh Kumar Singh, Dinesh Rangappa, Nishant Kumar, Jyoti Shah, Vivek Kumar, R. K. Kotnala, Tailoring the physical properties of non‑molar potassium‑substituted magnesium ferrite nanomaterials and its applications in hydroelectric cell, Applied Physics A (2023) 129:15 https://doi.org/10.1007/s00339-022-06291-5. Parveen Kumar, Raghav Sharma, Mohammad Saifullah, Adarsh Singh, Vanita Bhardwaj, Manish Kumar Kansal, Vivek Verma, Effect of K + cation doping on structural and morphology of MgFe 2 O 4 and their role in green electrical energy generation, J. Alloy. Compd. 944 (2023) 169169, https://doi.org/10.1016/j.jallcom.2023.169169. R. K. Kotnala, Rojaleena Das, Jyoti Shah, Sanjeev Sharma, C. Sharma, P.B. Sharma, Red mud industrial waste translated into green electricity production by innovating an ingenious process based on Hydroelectric Cell, J. Environ. Chem. Eng. 10 (2022) 107299, https://doi.org/10.1016/j.jece.2022.107299. Jyoti Jangra, Suman Singh, Jyoti Shah , R. K. Kotnala, Green electricity production through iron oxide and Fe-MOF composite based hydroelectric cell , Appl. Mater. Today 43 (2025)102652, https://doi.org/10.1016/j.apmt.2025.102652. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7000548","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":480516197,"identity":"ff08e369-cec0-4332-8041-17594b3b7f12","order_by":0,"name":"Neelam Singh","email":"","orcid":"","institution":"Hansraj College, University of Delhi","correspondingAuthor":false,"prefix":"","firstName":"Neelam","middleName":"","lastName":"Singh","suffix":""},{"id":480516198,"identity":"8e705929-e06b-418f-a584-73c28a0cf3b0","order_by":1,"name":"Seema Dhankhar","email":"","orcid":"","institution":"Hindu College, University of 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2","display":"","copyAsset":false,"role":"figure","size":319790,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eX-Ray diffraction pattern of 15 mol% Li doped SnO\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2 \u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003esamples sintered at different temperature.\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7000548/v1/a7fcb1388860df99e0044cb2.png"},{"id":86153658,"identity":"23e8c97a-2f37-4cdf-81d4-937c09fdf039","added_by":"auto","created_at":"2025-07-07 10:37:09","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":656833,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScanning Electron Micrographs of 15 mol% doped SnO\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2 \u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003esamples sintered at different 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10:37:09","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":117946,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eI-V response of the samples with (wet) and without water (dry) medium at room temperature.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7000548/v1/9f2dc94c40dbcae4811020f8.png"},{"id":86153660,"identity":"129bed8e-6637-494b-90c7-5124f7f997cb","added_by":"auto","created_at":"2025-07-07 10:37:09","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":304803,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eVariation of dielectric constant of samples with and without water at room 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Population is increasing day by day worldwide that causes a more demand for electrical energy. \u0026nbsp;At the present time with the escalating global energy crisis and environmental concern, we are running with scarcity of energy, it is call for all of us to pay attention toward diminishing natural resources of energy [1, 2]. Word is facing problem of increasing demand of energy and decreasing conventional energy sources such as natural gas, oil, coal etc. Conventional energy sources can cause several types of pollutions like air pollution, green house gasses and acid rain which causing severe effect on human health [3, 4]. \u0026nbsp;The need of the hour is to invent and use alternative sustainable green energy sources. The extraction and utilization of non-conventional energy will not only help in meeting energy demands but also help in their development. Since non-conventional energy sources provide environment-friendly, non-polluting energy, they help keep the atmosphere and environment clean and safe. As we know that solar energy is clean, pollution free, natural and one of the majorly explored source of renewable energy [5, 6]. From many years scientists has been working on this area to discover new methods to replace conventional sources of energy with renewable sources of energy. It provides a reliable and effective way for solving the problem of energy crises and environmental protection. Solar cell is one of them and majorly used to produce electrical energy. But there are some limitations of solar cells due to which we have to look for alternate source of green energy [7, 8]. The initial cost of purchasing a solar system is fairly high. This includes paying for solar panels, inverter and batteries. Solar panels are weather dependent. Few cloudy, rainy days can have a noticeable effect on the energy system. Solar energy has to be used right away, or it can be stored in large batteries. These batteries, used in off the grid solar systems, can be charged during the day so that the energy is used at night. So, we can say that solar energy storage is expensive.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Recently Hydroelectric Cell device has been invented as a unique, revolutionary and path breaking invention to generate green electricity without using any electrolyte/light/electricity [9, 10]. It is based on non-photocatalytic technique to dissociate water molecules into (H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e and OH\u003csup\u003e\u0026minus;\u003c/sup\u003e) ions on the surface of oxide materials without supplying any external energy like electrolyte/light/temperature, generates green electricity [11]. Energy generated by HEC is comparable to solar cells and fuel cells power output at low cost. A very little capital-intensive industry can produce it. The adsorption of water on oxide surface can be in different manner. First, well-ordered ionic single-crystal samples are often nonreactive for H\u003csub\u003e2\u003c/sub\u003eO dissociation. It may be due to that the dissociation of water on the surface is by reaction at the defect sites and facet edges in the oxide polycrystalline samples, and defect sites are very less on the single crystals. The influence of defect lattice sites and oxygen deficit surfaces are important for dissociation of water. The second distinctive feature of H\u003csub\u003e2\u003c/sub\u003eO adsorption is the formation of relatively strong chemisorption bonds on some ionic surfaces, so that molecular adsorbed H\u003csub\u003e2\u003c/sub\u003eO can be stable even at room temperature [12, 13]. Water adsorption at metal-oxide surfaces is governed by a subtle balance between water-water hydrogen bonding and water-metal oxide interactions, which together determine the stability of the water structures formed. The energy produced by HEC can be utilized in domestic residential applications in decentralized mode at low cost because conventional usage of electrical energy is associated with huge expense of electrical transmission and distribution. It can also supply the electrical needs of the household and in automotive engine as a clean energy source. Production and usage of such cells is not capital intensive unlike electrical power generation systems. Technological improvements could make invented cell as an electrical energy source imbibed with an economic reality in bigger scale.\u0026nbsp;Although a considerable amount of research is required to generate HEC cell panels and their maintenance for large scale usage in the form of a power station. The future of power generation will certainly include hydroelectric cell systems.\u003c/p\u003e\n\u003cp\u003eIn this work, lithium doped SnO\u003csub\u003e2\u003c/sub\u003e based hydroelectric cells were synthesized by solid state sintering method and investigation was made on the role of microstructure, ionic conduction and electricity generation.\u0026nbsp;\u003c/p\u003e"},{"header":"2.\tExperimental ","content":"\u003cp\u003e\u003cstrong\u003e2.1. \u0026nbsp; \u0026nbsp;Synthesis method\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe 15 mol % Lithium doped SnO\u003csub\u003e2\u003c/sub\u003e samples were synthesized by solid state sintering method. Lithium carbonate (LiCO\u003csub\u003e3\u003c/sub\u003e) and stannic oxide (SnO\u003csub\u003e2\u003c/sub\u003e) were used as precursors. Stoichiometric molar ratio of these precursors was taken, mixed and ground for 6-7 hours in acetone medium to get uniform mixing of powders. The obtained powder samples were pre-sintered at 500\u003csup\u003eo\u003c/sup\u003e C for 5 h followed by grinding for 2 hours. Thereafter, pre-sintered powder samples were pelletized into 2-inch diameter circular pellets then final sintering was carried out at 500, 600, 700, 800 and 900 \u003csup\u003eo\u003c/sup\u003eC for 5 hours to obtain the required mechanical strength of all samples to use in cell. Subsequently, one face of these sintered 2-inch diameter circular pellets was attached with zinc plate (acts as anode) and other face is pasted with silver (acts as cathode) as shown in Figure 1. The structural characterization of samples was carried out by the X-ray diffraction (XRD, Bruker D4, step size = 0.02\u0026ordm;) technique using Cu Ka\u0026nbsp;radiation (wavelength\u0026nbsp;l\u0026nbsp;= 1.5406 \u0026Aring;) and FTIR (4000\u0026ndash;400 cm\u003csup\u003e-1\u003c/sup\u003e, Perkin Elmer, UK). A field emission scanning electron microscope (JEOL/JSM-6610LV) was used to observe the microstructure details of the samples. Dielectric studies were performed to investigate ionic dissociation of water and its conduction in cell using impedance analyzer E4900A. Current and voltage generated by each hydroelectric cell was measured by digital multi meter (DMM).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 Structural analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll the samples were characterized by X-ray diffraction (XRD) method using Cu-Ka\u0026nbsp;radiation (\u0026lambda;= 1.5406\u0026nbsp;Ǻ) at room temperature in the 2q\u0026nbsp;range of 20-80\u003csup\u003e0\u003c/sup\u003e to analyse the phase formation. Figure 2 shows the typical XRD pattern of 15 mol % Lithium doped SnO\u003csub\u003e2\u003c/sub\u003e samples sintered at 500, 600, 700, 800 and 900 \u003csup\u003e0\u003c/sup\u003eC. All the samples show good crystallization, with well-defined diffraction patterns corresponding to planes (110), (101), (200), (111), (211), (220) (002), (310), (112), (301), (202) and (321) between 2q\u0026nbsp;range of 20-80\u003csup\u003e0\u003c/sup\u003e. Obtained structure of the prepared samples is exhibiting tetragonal rutile structure as confirmed from JCPDS file (JCPDS 41-1445) [14]. There is no extra peak observed except SnO\u003csub\u003e2\u003c/sub\u003e tetragonal rutile structure which indicates complete doping of lithium. Detailed and precise analysis of structural parameters of polycrystalline SnO\u003csub\u003e2\u003c/sub\u003e samples was conducted by Rietveld refinement using FullProf software. Lattice parameters were calculated by refining XRD data of all samples. Tetragonal structure with space group of P42/mnm was considered for Rietveld refinement of pristine and doped SnO\u003csub\u003e2\u003c/sub\u003e samples. Figure 2 clearly shows that observed and calculated patterns are in good agreement. The quality of Rietveld refinement was ensured by profile factor (Rp), weight difference measured and calculated values (Rwp), expected profile parameters (Rexp) and goodness of the fit indicator (\u003cem\u003ex\u003c/em\u003e\u003cstrong\u003e\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e). It can be observed from table 1 that there are no significant changes in lattice parameters of samples with sintering temperature. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable1. Rietveld refined lattice parameters and estimated reliability factors for the 15 mol% Li-doped SnO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003esamples sintered at different temperature\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 93px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSample sintering temperature\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePhase/crystal structure\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 167px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCell (\u0026Aring;)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eR-factor\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRp\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRwp\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;c\u003c/strong\u003e\u003cstrong\u003e\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 93px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e500\u0026nbsp;\u003c/strong\u003e ̊\u003cstrong\u003eC\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP42/mnm\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eTetragonal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 167px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ea = b = 4.7554\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003ec = 3.1838\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eV = 71.9989 (\u0026Aring;\u003csup\u003e3\u003c/sup\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e7.49\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e9.51\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e3.41\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 93px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e600\u0026nbsp;\u003c/strong\u003e̊\u003cstrong\u003eC\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP42/mnm\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eTetragonal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 167px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ea = b = 4.7396\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003ec = 3.1766\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eV = 71.3599 (\u0026Aring;\u003csup\u003e3\u003c/sup\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e7.37\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e9.26\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.81\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 93px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e700\u0026nbsp;\u003c/strong\u003e̊\u003cstrong\u003eC\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP42/mnm\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eTetragonal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 167px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ea = b = 4.7449\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003ec = 3.1865\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eV = 71.7416 (\u0026Aring;\u003csup\u003e3\u003c/sup\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e4.79\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e6.23\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.31\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 93px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e800\u0026nbsp;\u003c/strong\u003e̊\u003cstrong\u003eC\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP42/mnm\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eTetragonal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 167px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ea = b = 4.7420\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003ec = 3.1868\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eV = 71.6607 (\u0026Aring;\u003csup\u003e3\u003c/sup\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e5.70\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e7.15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.88\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 93px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e900\u0026nbsp;\u003c/strong\u003e̊\u003cstrong\u003eC\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP42/mnm\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eTetragonal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 167px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ea = b = 4.7416\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003ec = 3.1886\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eV = 71.6879 (\u0026Aring;\u003csup\u003e3\u003c/sup\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e6.22\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e7.89\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.00 \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e2.3\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Morphological studies\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe surface morphology of Li doped SnO\u003csub\u003e2\u003c/sub\u003e samples have been recognized at 100.00 K X magnification using FESEM. Figure 3 depicts the FESEM micrographs of prepared\u003csub\u003e\u0026nbsp;\u003c/sub\u003esamples sintered at 500\u0026nbsp;̊C\u003cstrong\u003e,\u0026nbsp;\u003c/strong\u003e600 ̊C, 700 ̊C, 800 ̊C and 900 ̊C. To evaluate the grain size of these samples, a histogram plots were obtained using image j software and the average grain size was evaluated to be around 20-25 nm. Average sampling was taken around 100 to estimate the distribution of grains. Morphology of SnO\u003csub\u003e2\u003c/sub\u003e Samples was significantly affected by the sintering temperatures. Figure 3 reveal that sample sintered at 500 ̊C exhibits a flakes-like structure and average grain growth around 25 nm. It also can be notice that distribution of grain is symmetrical. Samples sintered at 500 ̊C\u003cstrong\u003e,\u0026nbsp;\u003c/strong\u003e600 ̊C, 700 ̊C and 800 ̊C have nano-sized grain distribution with porosity, while, sample sintered at 900 ̊C has drastic change in microstructure. \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eHydroelectric properties\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe working principle of hydroelectric cell is adsorption of water molecule in the oxide samples and its splitting into (OH\u003csup\u003e-\u003c/sup\u003e, H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e) ions and their conduction towards electrodes. As H\u003csub\u003e2\u003c/sub\u003eO molecules interact to oxide surface, immediately it split into ions (H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e, OH\u003csup\u003e-\u003c/sup\u003e) due to the defect lattice sites and oxygen deficit surfaces [15]. The dissociation of H\u003csub\u003e2\u003c/sub\u003eO molecule is mainly dependent on the electronegativity, number of unsaturated metal cations and metal oxide surface defects. Motion of dissociated H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e ions through proton hopping while migration of OH\u003csup\u003e\u0026minus;\u003c/sup\u003e ions takes place through interconnected defective crystallite boundaries as a result output electrical current is generated. Also, dissociated H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e ions produce localized electric field as they trapped within mesopores of oxide sample which leads to further instant dissociation of physisorbed water molecules spontaneously as represented by eq. 1. The hydroxide ions migrate towards the Zn electrode where zinc gets oxidized to Zn(OH)\u003csub\u003e2\u003c/sub\u003e (eq. 2) \u0026nbsp;while H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e ions towards the Ag electrode where they get reduced with evolution of H\u003csub\u003e2\u003c/sub\u003e gas (eq. 3) by capturing electrons from the Zn anode. This motion of ions towards their corresponding electrodes generates 0.95 V in the hydroelectric cell.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAt SnO\u003csub\u003e2\u003c/sub\u003e surface: \u0026nbsp; \u0026nbsp; \u0026nbsp; 4H\u003csub\u003e2\u003c/sub\u003eO \u0026nbsp; \u0026nbsp; \u0026rarr; \u0026nbsp; \u0026nbsp;2H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e + 2OH\u003csup\u003e-\u003c/sup\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;(eq. 1)\u003c/p\u003e\n\u003cp\u003eAt anode: \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Zn + 2OH\u003csup\u003e-\u003c/sup\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026rarr; \u0026nbsp; \u0026nbsp;Zn(OH)\u003csub\u003e2\u003c/sub\u003e + 2e\u003csup\u003e-\u0026nbsp;\u003c/sup\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; (eq. 2)\u003c/p\u003e\n\u003cp\u003eAt cathode: \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;2e\u003csup\u003e-\u003c/sup\u003e + 2H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e\u0026nbsp; \u0026nbsp; \u0026rarr; \u0026nbsp; \u0026nbsp;2H\u003csub\u003e2\u003c/sub\u003eO + H\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;(eq. 3)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFrom the above reactions we can observed that the voltage generated between the electrodes is E\u003csub\u003ecell\u003c/sub\u003e = 0.22 + 0.76 = 0.98 V. To investigate the power production properties of SnO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003ecell, we have taken the observations of current for all prepared samples for 2 hour after spray the deionized water on samples. We repeated measurement in same sample as well in different sets of samples to observe the consistency/reproducibility of results. 15 % Li doped SnO\u003csub\u003e2\u003c/sub\u003e based hydroelectric cell, sintered at 500 ̊\u003cstrong\u003eC\u003c/strong\u003e delivers maximum current ~65 mA. While, a decay is observed in the short-circuit current for all samples. Decrease in current with time may be attributed to oxidation of zinc electrode and concentration loss [16]. It is interesting to note that sample sintered at 600 ̊C exhibiting more stable current response.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eDC Conductivity measurements\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo confirm the dissociation of water molecule and their conduction in the oxide medium was further confirm by I-V response of all the samples in dry and wet state at the room temperature. First current versus voltage response were recorded at dried samples (samples were placed at 100 ̊C for 1 h in oven) then at wet state (dip in deionized water for 1 min). It can be observed that all samples are showing almost ten times enhanced conductivity in wet state as shown in Figure 5. It concludes that water dissociation occurs in oxides and ions contribute in conductivity. In metal oxides, the absorbed water molecules on the surface and grain boundary are considered to be valuable probable path for proton transport at low temperature because of the high hydration properties of metal oxide compounds [17].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.6 Dielectric Properties\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDielectric properties have been utilized to further investigate the role of microstructural properties on the water dissociation and ionic diffusion abilities of synthesized samples. Dielectric properties of samples were investigated in dry (without water) as well as wet (with water) state at the room temperature in the frequency range of 100 Hz to 1MHz by using impedance analyzer E4900A. Dielectric response of all samples has been shown in Figure 6. At lower frequency region dielectric response of wet samples is higher by magnitude of 10 which is due to ionic conduction of dissociate water molecules while in higher frequency range both have almost same constant dielectric values. So, the water molecules dissociation is established with these high dielectric values in wet samples [18].\u0026nbsp;\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003e15 mol % Lithium doped SnO\u003csub\u003e2\u003c/sub\u003e samples sintered at 500, 600, 700, 800 and 900 \u003csup\u003e0\u003c/sup\u003eC were synthesized by solid state sintering method. Phase formation of all the samples has been confirmed by XRD. The lattice parameters were calculated by using Rietveld refinement technique. Surface morphology was depicted by using FESEM images and exhibits increase in grain size with sintering temperature. In all the synthesized hydroelectric cells, current and voltage generation have been investigated in detail. Maximum sustainable current was achieved for sample sintered at 500\u0026nbsp;\u003csup\u003e0\u003c/sup\u003eC. These results motivate and open an opportunity to further investigate more sustainable and high-power hydroelectric cells in view of commercial applications.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgement\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors extend their gratitude to the Principal, Hindu College, University of Delhi for giving continual inspiration and drive to complete this effort.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eEnergy Statistics Pocketbook, Department of Economic and Social Affairs Statistics Division, United Nations 2024.\u003c/li\u003e\n\u003cli\u003eRenewable Energy Statistics 2023-24, Government of India, www.mnre.gov.in. \u003c/li\u003e\n\u003cli\u003eSaliha Saher, Sam Johnston, Ratu Esther-Kelvin, Jennifer M. 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Eng. 10 (2022) 107299, https://doi.org/10.1016/j.jece.2022.107299.\u003c/li\u003e\n\u003cli\u003eJyoti Jangra, Suman Singh, Jyoti Shah , R. K. Kotnala, Green electricity production through iron oxide and Fe-MOF composite based hydroelectric cell , Appl. Mater. Today 43 (2025)102652, https://doi.org/10.1016/j.apmt.2025.102652.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Hydroelectric Cell, Water Dissociation, Porous Oxide, Green Energy","lastPublishedDoi":"10.21203/rs.3.rs-7000548/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7000548/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"In recent years, green energy sources have been attracted considerable great attention, since these sources are able to produce low-cost, clean, efficient and sustainable energy. A hydroelectric cell generates electrical energy in milliwatts range using only few drops of water. In recent years, scientific and technological research have been done to increase its efficiency followed by explanation of basic working principle. This paper presents comprehensive and significant research conducted, current state of research and development, on-going challenges. Moreover, fabrication of hydroelectric cell with good efficiency durability is still a challenging task. Role of materials, microstructure, sample size in ionic conductivity and electricity generation by hydroelectric cells have been discussed in details.","manuscriptTitle":"Role of sintering temperature on microstructure, ionic conductivity and green electricity generation of hydroelectric cell","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-07 10:37:04","doi":"10.21203/rs.3.rs-7000548/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"39298062-6827-41e2-860c-ec0181042c0c","owner":[],"postedDate":"July 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-27T16:53:24+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-07 10:37:04","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7000548","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7000548","identity":"rs-7000548","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}