12-Ah-Level Li-Ion Pouch Cells Enabling Fast Charging at Temperatures between −20 and 50 °C

Achieving fast-charging capabilities in Li-ion batteries (LIBs)—charging 80% of the battery capacity within 15 minutes—while maintaining an acceptable cycle life remains challenging due to various polarizations occurring at elevated charge rates. Such a goal is more tough at subzero, as temperature reduction slows the kinetics process including electrolyte mass transport and electrode charge transfer, substantially increasing the risk of lithium plating. Herein, it is found that adding LiFSI to a LiPF₆ carbonate-based electrolyte alters the Li⁺ solvation structure, endowing the dual-salt electrolyte with a higher Li⁺ diffusion coefficient and lower desolvation energy. Benefit from the smaller structural change and the formation of a robust, conductive solid electrolyte interphase, the 12Ah-pouch cells based on LiNi_0.52Co_0.2Mn_0.28O₂ cathodes and graphite anodes demonstrate fast-charging capabilities and stable cycling performance across a wide temperature range of −20 to 50 ℃: charging 89% and 93% of pouch cell capacity within 4 minutes at 25 and 50 ℃ and 82% within 15 minutes at −20 ℃, maintaining capacity retention of 94% after 2000 cycles at 8C at 0 ℃ and 89% after 350 cycles at −20 ℃ at 4C. This work might offer new insights into enhancing the fast-charging capabilities of LIBs under extreme conditions.