Enabling Long Cycling with Excellent Structure Stability for High-Nickel Layered Cathodes in Lithium Metal Batteries

Rechargeable Li metal batteries (LMBs) constructed fromLi metaland high-Ni NMCs have attracted much attention because of their highenergy density in electrical vehicles. The choice of electrolyte playsa crucial role in determining the performance of Li||high-Ni NMC LMBs.In this work, we investigated the electrochemical performance andmicrostructure change of Li||0.7Nb-NMC 9055 LMBs using ether-basedelectrolyte (LiFSI-1.2DME-3TTE) and carbonate electrolyte(1 M LiPF6 in EC/DMC). The results show that ether-basedelectrolyte can significantly enhance the cycling life of Li||0.7Nb-NMC9055 battery, providing a capacity of 203 mAh/g vs 179 mAh/g (carbonateelectrolyte) for 150 cycles without voltage decay at C/5 charge andC/2 discharge rates. The excellent electrochemical performance (capacityand voltage) originates from the perfect structural stability confirmedby the dQ/dV versus V curves, which was further supported by electrochemical impedancespectroscopy test, showing nearly no surface charge transfer resistanceincrease in ether-based electrolyte, versus continuous growth in carbonateelectrolyte.