Small modification, striking improvement: super-fast charging over a wide temperature range by simply replacing n-propyl acetate with isopropyl acetate

Abstract

The combination of high-nickel cathodes with lithium metal anodes is widely considered a promising solution to alleviate range anxiety. However, challenges such as limited fast-charging capacity and rapid degradation persist when using carbonate-based electrolytes. While many researchers predominantly focus on solvation structures, we have strategically tailored the electrolyte formulation by employing isopropyl acetate as the primary solvent, evidenced by interfacial interactions. Compared to n-propyl acetate, isopropyl acetate reduced the interaction with the electrode surface, promoted tighter adsorption of the electrolyte ion network within the inner Helmholtz layer, and ultimately enhanced the dynamic stability of the lithium metal interface. In Li‖NCM811 cells, this electrolyte demonstrates a 4.5 V cutoff and sustains 88.6% capacity retention over 200 cycles at a high rate of 15C. Additionally, this electrolyte demonstrates stable cycling performance at elevated rates of 1C and 5C at temperatures of 60 °C and −20 °C, respectively, while maintaining stability even at a rate of 10C under poor electrolyte conditions with thin lithium layers, indicating significant application potential. These studies reveal that the electrolyte distribution at the electrode interface affects the electrochemical process and the formation of the electrode–electrolyte interphase significantly, offering new ideas for future electrolyte research and design.