Temperature-dependent interphase formation and Li+ transport in lithium metal batteries

• DOI: 10.1038/s41467-023-40221-0
• Publication Date: 2023-07-25T16:04:34Z
• Authors: Suting Weng; Xiao Zhang; Gaojing Yang; Simeng Zhang; Bingyun Ma; Qiuyan Liu; Yue Liu; Chengxin Peng; Huixin Chen; Hailong Yu; Xiulin Fan; Tao Cheng; Liquan Chen; Yejing Li; Zhaoxiang Wang; Xuefeng Wang
• Keywords: HOMO/LUMO

High-performance Li-ion/metal batteries working at a low temperature (i.e., <-20 °C) are desired but hindered by the sluggish kinetics associated with Li+ transport and charge transfer. Herein, temperature-dependent behavior during Li plating is profiled various characterization techniques, suggesting that diffusion through solid electrolyte interface (SEI) layer key rate-determining step. Lowering not only slows down transport, also alters thermodynamic reaction of decomposition, resulting in different pathways forming an SEI consisting intermediate products rich organic species. Such metastable unsuitable for efficient transport. By tuning solvation structure lower lowest unoccupied molecular orbital (LUMO) energy level polar groups, such as fluorinated electrolytes like 1 mol L-1 lithium bis(fluorosulfonyl)imide (LiFSI) methyl trifluoroacetate (MTFA): fluoroethylene carbonate (FEC) (8:2, weight ratio), inorganic-rich more readily forms, which exhibits enhanced tolerance to change (thermodynamics) improved (kinetics). Our findings uncover kinetic bottleneck provide directions enhance kinetics/thermodynamics low-temperature performance constructing interphases.