Cooperation Between Methyl Acetate Solvent and Binder Remarkably Improves the Low-Temperature Performance of the LiNi_0.5Mn_1.5O₄ Cathode

Li₄Ti₅O₁₂ (LTO)/LiNi_0.5Mn_1.5O₄ (LNMO) batteries have appealing features, such as suitable energy density and high safety. A proper binder of the LNMO cathode and electrolyte can improve the performance of batteries. Herein, we first combined the polyacrylic acid (PAA) binder with an ester-based electrolyte due to their homologous structure. This system has better performance than other binders of LNMO cathode, like poly­(vinylidene fluoride) (PVDF), styrene–butadiene rubber (SBR), and polytetrafluoroethylene (PTFE). In the methyl acetate (MA) electrolyte, the LTO/LNMO battery with the PAA binder exhibited the highest discharge capacity (137 mAh g^–1 at 0.5 C) and the best rate performance (112 mAh g^–1 at 5 C). In addition, MA boosted the low-temperature performance of this battery, which can work at −40 °C with a remarkable reversible capacity of 90 mAh g^–1 and a discharge capacity of 140 mAh g^–1.