Influence of lithium difluorophosphate additive on the high voltage LiNi0.8Co0.1Mn0.1O2/graphite battery

Abstract Lithium-ion batteries (LIBs) possessing high energy densities are driven by the growing demands of electric vehicles (EVs) and hybrid electric vehicles (HEVs). One of the most effective strategies to improve the energy density of LIBs is to enlarge the charge cut-off voltage via a lithium salt additive for the conventional electrolyte system. Herein, lithium difluorophosphate (LIDFP) is employed to optimize and reconstruct the composition of the structure and interface for both cathode and anode, which can effectively restrain the oxidation decomposition of electrolyte as well as refrain the dissolve out of transition metals. The LiNi0.8Co0.1Mn0.1O2 (LNCM811)/graphite pouch cell with 1 wt% LIDFP in electrolyte delivers a discharge capacity retention of 91.3% at a high voltage of 4.4 V over 100 cycles, which is higher than the 82.0% of that without LIDFP additive. Additionally, the remaining capacity of LNCM811/C battery with 1 wt% LIDFP additive which is left at 60 °C for 14 days is 85.2%, and the recovery capacity is 93.3%. The LIDFP-containing electrolyte demonstrates a great application future for the LiBs operating under the high-voltage condition and high-temperature storage performance.