Ion–Solvent Complexes Promote Gas Evolution from Electrolytes on a Sodium Metal Anode |
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| Authors: | Xiang Chen Xin Shen Prof Bo Li Hong‐Jie Peng Dr Xin‐Bing Cheng Bo‐Quan Li Xue‐Qiang Zhang Prof Jia‐Qi Huang Prof Qiang Zhang |
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| Institution: | 1. Beijing Key Laboratory of Green Chemical, Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, P. R. China;2. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, P. R. China;3. Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, P. R. China;4. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin, P. R. China |
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| Abstract: | Lithium and sodium metal batteries are considered as promising next‐generation energy storage devices due to their ultrahigh energy densities. The high reactivity of alkali metal toward organic solvents and salts results in side reactions, which further lead to undesirable electrolyte depletion, cell failure, and evolution of flammable gas. Herein, first‐principles calculations and in situ optical microscopy are used to study the mechanism of organic electrolyte decomposition and gas evolution on a sodium metal anode. Once complexed with sodium ions, solvent molecules show a reduced LUMO, which facilitates the electrolyte decomposition and gas evolution. Such a general mechanism is also applicable to lithium and other metal anodes. We uncover the critical role of ion–solvent complexation for the stability of alkali metal anodes, reveal the mechanism of electrolyte gassing, and provide a mechanistic guidance to electrolyte and lithium/sodium anode design for safe rechargeable batteries. |
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| Keywords: | electrochemistry electrolytes first-principles calculations gas evolution alkali metal batteries |
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