Fast Solvation Dynamics Enabled by High Entropy Electrolyte Design for Low Temperature Lithium-Ion Batteries

초록

Low-temperature operation of lithium-ion batteries (LIBs) remains challenging due to sluggish Li+ transport and increased interfacial resistance under subzero conditions. Although propylene carbonate (PC) offers favorable fluidity at low temperatures, its practical use is limited by graphite exfoliation and slow interfacial kinetics arising from strong Li+-solvent interactions. Here, we report a high-entropy electrolyte design based on a PC-dominant solvent system for low-temperature LIBs. By combining PC with two carbonate-based and two nitrile-based solvents, the electrolyte simultaneously forms a stable, low-resistance solid electrolyte interphase while diversifying the solvation environment. This solvent diversification weakens PC solvation and accelerates Li+ solvation dynamics, exhibiting a solvation exchange rate two times faster than that of a reference electrolyte. Consequently, the electrolyte significantly lowers interfacial resistance and enhances charge-transfer kinetics, delivering excellent rate capability and stable cycling performance at -30 degrees C. This study demonstrates the effectiveness of entropy-driven solvent design for enabling LIB operation under extreme low-temperature conditions.

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