Mitigating Swelling of the Solid Electrolyte Interphase using an Inorganic Anion Switch for Low‐temperature Lithium‐ion Batteries

• Published in: Angewandte Chemie International Edition Vol. 62; no. 16; pp. e202300384 - n/a
• Main Authors: Liang, Jia‐Yan, Zhang, Yanyan, Xin, Sen, Tan, Shuang‐Jie, Meng, Xin‐Hai, Wang, Wen‐Peng, Shi, Ji‐Lei, Wang, Zhen‐Bo, Wang, Fuyi, Wan, Li‐Jun, Guo, Yu‐Guo
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 11.04.2023
• Edition: International ed. in English
• Subjects: Anion Switch; Anions; Electrochemical analysis; Electrochemistry; Graphite; Intercalation; Interphase; Li-Ion Battery; Lithium; Lithium-ion batteries; Low temperature; Low-Temperature Electrolyte; Permeability; Sheaths; Solid Electrolyte Interphase; Solid electrolytes; Solvation; Solvents; Swelling; Swelling Chemistry; Solid Electrolyte Interphase; Swelling Chemistry; Li-Ion Battery; Anion Switch; Low-Temperature Electrolyte
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202300384

In overcoming the Li+ desolvation barrier for low‐temperature battery operation, a weakly‐solvated electrolyte based on carboxylate solvent has shown promises. In case of an organic‐anion‐enriched primary solvation sheath (PSS), we found that the electrolyte tends to form a highly swollen, unstable solid electrolyte interphase (SEI) that shows a high permeability to the electrolyte components, accounting for quickly declined electrochemical performance of graphite‐based anode. Here we proposed a facile strategy to tune the swelling property of SEI by introducing an inorganic anion switch into the PSS, via LiDFP co‐solute method. By forming a low‐swelling, Li3PO4‐rich SEI, the electrolyte‐consuming parasitic reactions and solvent co‐intercalation at graphite‐electrolyte interface are suppressed, which contributes to efficient Li+ transport, reversible Li+ (de)intercalation and stable structural evolution of graphite anode in high‐energy Li‐ion batteries at a low temperature of −20 °C. Inclusion of difluorophosphate anion in the primary solvation sheath of a weakly‐solvated electrolyte helps to switch the swelling properties of solid electrolyte interphase (SEI) on a graphite (Gr) composite anode. By forming a low‐swelling, Li3PO4‐enriched SEI, reversible Li+ (de)intercalation was enabled at a stable Gr‐electrolyte interface, contributing to improved low‐temperature electrochemical performance of a Li‐ion battery.