Stabilizing lithium metal anode by regulating lithium ion solvation structure in ether electrolytes with steric effect

B Jiang and YY Gu and L Wu and X Xi and YM Wu and YZ Su and RL Liu and DQ Wu, ELECTROCHIMICA ACTA, 522, 145909 (2025).

DOI: 10.1016/j.electacta.2025.145909

The solvation structure of lithium ion (Li+) in the electrolyte is closely related to the stability of electrodes in lithium-ion batteries. Herein, the influence of steric effect on the solvation structures of Li+ in ether electrolytes was investigated with three ethers containing different alkyl substituents, 1,2-dimethoxyethane (DME), acetaldehyde dimethyl acetal (ADMA) and 2,2-dimethoxypropane (DMOP). With lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as lithium salt, the ether electrolytes manifested steric effect depended physical properties. The electrochemical tests indicated that the introduction of steric hindrance could effectively improve the stabilization effect of the ether electrolyte on lithium metal anode. The electrolyte with DMOP as the solvent presented a cycling life of >400 h for Li | Li symmetric cells at a current density of 1 mA cm(-2) and a charge/discharge capacity of 1 mA h cm(-2), and a Coulombic efficiency (CE) of more than 95 % for Li | Cu cells at a current density of 0.5 mA cm(-2) and a deposition capacity of 1 mA h cm(-2).

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