Electrolyte Engineering Empowers Li||CF<i><sub>x</sub></i> Batteries to Achieve High Energy Density and Low Self‐Discharge at Harsh Conditions
Yukang Xiao, Xunxin Chen, Junhua Jian, Yong Cheng, Yue Zou, Yu Su, Qilong Wu, Chao Tang, Zhongru Zhang, Ming‐Sheng Wang, Jianming Zheng, Yong Yang
Abstract
Abstract Given its exceptional theoretical energy density (over 2000 Wh kg −1 ), lithium||carbon fluoride (Li||CF x ) battery has garnered global attention. N ‐methylpyrrolidone (NMP)‐based electrolyte is regarded as one promising candidate for tremendously enhancing the energy density of Li||CF x battery, provided self‐discharge challenges can be resolved. This study successfully achieves a low self‐discharge (LSD) and desirable electrochemical performance in Li||CF x batteries at high temperatures by utilizing NMP as the solvent and incorporating additional ingredients, including vinylene carbonate additive, as well as the dual‐salt systems formed by LiBF 4 with three different Li salts, namely lithium bis (oxalato)borate, lithium difluoro(oxalato)borate, and LiNO 3 . The experimental results unfold that the proposed methods not only minimize aluminum current collector corrosion, but also effectively passivate the Li metal anode. Among them, LiNO 3 exhibits the most pronounced effect that achieves an energy density of ≈2400 Wh kg −1 at a current density of 10 mA g −1 at 30 °C, nearly 0% capacity‐fade rate after 300 h of storage at 60 °C, and the capability to maintain a stable open‐circuit voltage over 4000 h. This work provides a distinctive perspective on how to realize both high energy density and LSD rates at high temperature of Li||CF x battery.