PNNL

Abstract

In recent years, significant progresses have been made on the cycle life of lithium (Li) metal batteries (LMBs). However, very limited results have been reported on their calendar life. In this work, the effect of calendar aging on the performance of high-voltage LMBs is systematically investigated. By using a fluorinated orthoformate based localized high concentration electrolyte, Li||LiNi0.8Mn0.1Co0.1O2 cells demonstrated highly stable calendar life (capacity recovery of 89.6%), minimum Li corrosion and cathode deterioration after 18-month storage at 0% state of charge (SOC) at 30?C. The cells stored at 100% SOC demonstrated a low average self-discharge rate of only 0.26%/day during 18-month storage. In comparison, the cells stored at 50% SOC exhibits faster capacity fade. Cells stored at 55 ?C show similar fading trend but accelerated calendar aging. These results demonstrate long-term calendar life of LMBs and shine the light on the best storage conditions required for their practical applications.