Статья

Steric Effect Tuned Ion Solvation Enabling Stable Cycling of High-Voltage Lithium Metal Battery

Yuelang ChenDepartment of Chemical Engineering, Stanford University, Stanford, California 94305, United StatesZhiao YuDepartment of Chemical Engineering, Stanford University, Stanford, California 94305, United StatesPaul E. RudnickiDepartment of Chemical Engineering, Stanford University, Stanford, California 94305, United StatesHuaxin GongDepartment of Chemical Engineering, Stanford University, Stanford, California 94305, United StatesZhuojun HuangDepartment of Materials Science and Engineering, Stanford University, Stanford, California 94305, United StatesSang Cheol KimDepartment of Materials Science and Engineering, Stanford University, Stanford, California 94305, United StatesJian‐Cheng LaiDepartment of Chemical Engineering, Stanford University, Stanford, California 94305, United StatesXian KongDepartment of Chemical Engineering, Stanford University, Stanford, California 94305, United StatesJian QinDepartment of Chemical Engineering, Stanford University, Stanford, California 94305, United StatesYi CuiDepartment of Materials Science and Engineering, Stanford University, Stanford, California 94305, United StatesZhenan BaoDepartment of Chemical Engineering, Stanford University, Stanford, California 94305, United States

2021en

ABI

Аннотация

1,2-Dimethoxyethane (DME) is a common electrolyte solvent for lithium metal batteries. Various DME-based electrolyte designs have improved long-term cyclability of high-voltage full cells. However, insufficient Coulombic efficiency at the Li anode and poor high-voltage stability remain a challenge for DME electrolytes. Here, we report a molecular design principle that utilizes a steric hindrance effect to tune the solvation structures of Li+ ions. We hypothesized that by substituting the methoxy groups on DME with larger-sized ethoxy groups, the resulting 1,2-diethoxyethane (DEE) should have a weaker solvation ability and consequently more anion-rich inner solvation shells, both of which enhance interfacial stability at the cathode and anode. Experimental and computational evidence indicates such steric-effect-based design leads to an appreciable improvement in electrochemical stability of lithium bis(fluorosulfonyl)imide (LiFSI)/DEE electrolytes. Under stringent full-cell conditions of 4.8 mAh cm–2 NMC811, 50 μm thin Li, and high cutoff voltage at 4.4 V, 4 M LiFSI/DEE enabled 182 cycles until 80% capacity retention while 4 M LiFSI/DME only achieved 94 cycles. This work points out a promising path toward the molecular design of non-fluorinated ether-based electrolyte solvents for practical high-voltage Li metal batteries.

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Идентификаторы

DOI: 10.1021/jacs.1c09006

Цитирования и источники

Цитирований: 3Использованных источников: 0

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