High entropy liquid electrolytes for lithium batteries

QD Wang and CL Zhao and JL Wang and ZP Yao and SW Wang and SGH Kumar and S Ganapathy and S Eustace and XD Bai and BH Li and M Wagemaker, NATURE COMMUNICATIONS, 14, 440 (2023).

DOI: 10.1038/s41467-023-36075-1

High-entropy alloys/compounds have large configurational entropy by introducing multiple components, showing improved functional properties that exceed those of conventional materials. However, how increasing entropy impacts the thermodynamic/kinetic properties in liquids that are ambiguous. Here we show this strategy in liquid electrolytes for rechargeable lithium batteries, demonstrating the substantial impact of raising the entropy of electrolytes by introducing multiple salts. Unlike all liquid electrolytes so far reported, the participation of several anionic groups in this electrolyte induces a larger diversity in solvation structures, unexpectedly decreasing solvation strengths between lithium ions and solvents/anions, facilitating lithium-ion diffusivity and the formation of stable interphase passivation layers. In comparison to the single-salt electrolytes, a low-concentration dimethyl ether electrolyte with four salts shows an enhanced cycling stability and rate capability. These findings, rationalized by the fundamental relationship between entropy-dominated solvation structures and ion transport, bring forward high-entropy electrolytes as a composition-rich and unexplored space for lithium batteries and beyond. Electrolytes, function as an ion conducting membrane between battery electrodes, are essential for rechargeable batteries. Here, the authors report high-entropy liquid electrolytes and reveal substantial impact of the increasing entropy on lithium-ion solvation structures for highly reversible lithium batteries.

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