Electrochemical lithium storage performance at high voltage and temperature of LiNi0.6Co0.2Mn0.2O2 cathode for Lithium-ion batteries by facile Mn3(PO4)2 dry coating

Abstract

Herein, we successfully synthesized the Mn3(PO4)2-coated LiNi0.6Co0.2Mn0.2O2 (MP-NCM) by the dry coating method, which is facile to apply to industrial applications. MP-NCM has improved electrochemical performance and storage properties compared to the bare sample under a high voltage cut-off condition of 4.55 V and a high-temperature environment of 60℃. MP-NCM exhibited a discharge capacity of 198.5 mAh g−1 and capacity retention of 96.6 % after 50 cycles at 60 °C with an electrode loading level of 11 ± 0.2 mg cm−2, and higher capacity retention of 70 % after storage. Remarkably, according to the direct current internal resistance (DCIR) measurement, MP-NCM showed an increased rate of resistance, which is 47 % and 40.2 % points lower than the bare sample in the charging and discharging modes respectively. The MP coating treatment introduced not only reduces cation-mixing by reconstructing the layered structure of the particle surface according to the doping of stable manganese ions but also serves to stabilize the surface according to the formation of Li3PO4.