S掺杂/Li2SO4包覆富锂锰基正极材料的电化学性能研究OA

In this study,S-doped and Li2SO4-coated Li-rich Mn-based cathode materials(NSLRMs)were synthesized using a combined solution and redox method.The microstructure and surface chemistry were characterized by transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).TEM revealed a uniform coating layer approximately 3-5 nm thick on the NSLRM surface,and XPS confirmed the coexistence of SO2-4 and S2-species.Electrochemical tests showed that the initial Coulombic efficiency of all modified materials exceeded 88%,which was significantly higher than that of the pristine material(LRM).After 300 cycles at 1 C,2%modified material(NSLRM2)retained a reversible specific capacity of 153 mAh/g with a capacity retention of 70.29%,outperforming the LRM(111.3 mAh/g and 48.79%,respectively).Furthermore,NSLRM2 delivered discharge capacities of 151.2 mAh/g and 116.8 mAh/g at 5 C and 10 C,respectively(compared to 121.3 mAh/g and 74.7 mAh/g for the LRM).The enhanced electrochemical performance is attributed to several factors:S-doping strengthens transition metal bonding with oxygen,while the Li2SO4 coating provides rapid Li+conduction pathways.In addition,S-doping-induced oxygen vacancies further facilitate Li+transport and suppress lattice oxygen release,thereby improving structural stability.This work provides an effective strategy for developing Li-rich Mn-based cathode materials with high specific capacities and excellent cycling stabilities,offering experimental insight for high-performance lithium-ion batteries.