Inhibiting gas generation to achieve ultralong-lifespan lithium-ion batteries at low temperatures

Summary

The notorious low-temperature sensitivity of contemporary lithium-ion batteries (LIBs) has long restricted their low-temperature applications. Introduction of high-content low-freezing-point solvents significantly expands the low-temperature operation border of LIBs. However, they react violently with metallic lithium (Li) plated at low temperatures (−20°C or lower), resulting in severe gas generation and a limited lifespan. We reveal the mechanism of gas generation and develop a high-concentration ethyl acetate (EA)-based electrolyte. The dense and uniform solid electrolyte interphase formed by the joint decomposition of rich anions and additive effectively passivate the plated Li at low temperatures. The proposed electrolyte enables the LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811)/graphite pouch cell to be stably cycled at −20°C and 0.2 C for a record-breaking lifetime of more than 1 year (1,400 cycles). The NCM811/graphite pouch cell exhibits good fast-charging capability (0.5 C) at −20°C with a capacity decay rate as low as 0.0097% per cycle during 4,000 cycles.