Highly concentrated solvation structure for reversible high-voltage lithium-ion battery at low temperature

Abstract

The commercial electrolytes exhibit subpar performance under low temperature and high voltage, severely limiting the application of lithium-ion batteries (LIBs) for extreme temperature and high energy density. As a groundbreaking advancement, the regulation of Li+ solvation structure was adopted and highly concentrated in this work, obtaining an improved electrolyte with excellent low-temperature and high-voltage performance. The electrolyte exhibited outstanding oxidation potential of 5.25 V and high ionic conductivity, maintaining transparency liquid even at −60 °C. Notably, the NCM811||Li cell exhibited high initial capacity (71.41 % of that at room temperature) at −40 °C 0.2C, with almost no capacity decay after 50 cycles. Impressively, the as-assembled NCM811||Graphite pouch battery (2.5 Ah) showed an initial capacity of 2.07 Ah at 0.1C under −30 °C, with an excellent capacity retention ratio of 84.53 % after 50 cycles. This work points out a promising approach for the practical application of high-voltage LIBs at low temperature.