Electrolyte Strategy Enables High‐Rate Lithium Carbon Fluoride (Li/CF<sub>x</sub>) Primary Batteries in All‐Climate Environments
Xunxin Chen, Gaopan Liu, Ang Fu, Yukang Xiao, Jipeng Sun, Zhongru Zhang, Yong Yang
Abstract
Abstract Lithium/carbon fluoride (Li/CF x ) batteries have garnered significant attention due to their exceptional theoretical energy density (2180 Wh kg −1 ) in the battery field. However, its inadequate rate capability and limited adaptability at low‐temperature are major bottlenecks to its practical application due to the low conductivity of CF x materials and electrochemical inertness of discharge products LiF. Herein, an efficient and novel functional electrolyte formula is disclosed with tin trifluoromethanesulfonate (Sn(OTf) 2 ) as an additive to solve these challenges. It is shown that Sn(OTf) 2 possessing reasonable Lewis acidity can effectively facilitate the dissolution of LiF during the discharging process. Thereafter, the CF x electrode materials exhibit excellent rate performance with 1145 Wh kg −1 at 15 000 mA g −1 (or 15 A g −1 , 30 °C) and high capacity retention of 95.8% at a low temperature of −50 °C compared with the operating temperature of 30 °C. Moreover, the Sn 2+ dissolved from Sn(OTf) 2 promotes the formation of Li‐Sn alloy on the lithium metal anode, effectively protecting the lithium metal anode, and Li/CF x battery can be well stored for over 1 000 h at 60 °C with negligible self‐discharge behavior. This work presents a novel electrolyte exploring strategy that can effectively guide the development of next‐generation electrolytes operating under extreme conditions.