Screening of F-containing electrolyte additives and clarifying their decomposition routes for stable Li metal anodes
Jijiang Liu, Wei Hao, Mingming Fang, Xin Chen, Yongteng Dong, Yuanmao Chen, Zhiyong Wang, Xinyang Yue, Zheng Liang
Abstract
Constructing a LiF-rich solid electrolyte interphase (SEI) is a feasible strategy for inhibiting lithium (Li) dendrites of Li metal anodes (LMAs). However, selecting appropriate F-containing additives with efficient LiF contribution is still under active research. Herein, a series of fluorinated additives with diverse F/C molar ratios are investigated, and we demonstrate that the hexafluoroglutaric anhydride (F6−0) holds the best capability to derive the LiF-rich SEI in regular carbonate electrolytes (RCEs). To ameliorate the decomposition kinetics of the F6−0, LiNO3 (LNO) as an adjuvant is further introduced in the system. As a result, the reduction efficiency of F6−0 is increased to 91% under the F6−0/LNO synergistic effect, enabling the LMA with a uniform LiF-rich SEI in the RCE with merely 4 vol. % F6−0/LNO (F6L) addition. The LiNi0.8Co0.1Mn0.1O2||Li-20μm full-cell with the F6L also showcases better cycling and rate performances than the cases with other F-containing additives. A F-containing additive with efficient LiF contribution is urgent for Li metal batteries. The authors report a hexafluoroglutaric anhydride additive with a 91% conversion, enabling the Li metal anode with a LiF-rich interphase in regular electrolyte.