Lithium Hexamethyldisilazide Endows Li||NCM811 Battery with Superior Performance

The construction of a stable cathode–electrolyte interphase (CEI) is key to improving the structural and interfacial stability of Ni-rich NCM811 cathodes. This work highlights lithium hexamethyldisilazide (LiHMDS) as an electrolyte additive that simultaneously facilitates the formation of a robust CEI on NCM811 and scavenges trace H2O and HF in the electrolyte, thereby markedly boosting the cycling performance of Li||NCM811 batteries. With a 4.5 V cut-off, cells using 0.6 wt% LiHMDS achieve up to 1000 cycles at 25 °C and 500 cycles at 60 °C with superior capacity retention compared to baseline electrolyte.