"Efficient Lithium Metal Cycling over a Wide Range of Pressures from an Anion-Derived Solid-Electrolyte Interphase Framework"

Hansen Wang : William Huang, Zhiao Yu, Wenxiao Huang, Rong Xu, Zewen Zhang, Zhenan Bao, Yi Cui; ACS Energy Letters, 02/12/21.

Additional Authors: William Huang, Zhiao Yu, Wenxiao Huang, Rong Xu, Zewen Zhang, Zhenan Bao, Yi Cui

Abstract:

Advanced electrolytes were developed to improve the cyclability of lithium (Li) metal anodes, yet their working mechanisms remain unclear. Here, we study the Li cycling performance under different pressures in a 1 M Li bis(fluorosulfonyl)imide/fluorinated 1,4-dimethoxybutane electrolyte. A consistently long cycle life is achieved over a wide range of pressures (30–600 psi). This is due to a completely different Li plating mode with more favorable deposition morphologies compared to that in a conventional carbonate electrolyte, which exhibits increasing cycle stability with increased pressure. We show that this is enabled by the properties of an anion-derived residual solid-electrolyte interphase (rSEI) framework on the electrode surface, an undercharacterized structure with profound implications for Li metal cycling. This anion-derived rSEI chemistry is likely the key to a prolonged cycle life of Li metal batteries and should be vigorously addressed in future electrolyte designs.