Significant Improvement of LiMn2O4 Cathode Capacity by Introducing Trace Ni During Rapid Microwave-induced Solution Combustion

LiMn2O4 cathodes are prepared by a rapid microwave-induced solution combustion method. Their initial discharge capacity is significantly improved by introducing trace Ni. For example, the LiMn1.975Ni0.025O4 (LMNO-0.025) cathode releases an initial discharge capacity of 134.1 mAh g−1 at 1 C, even 144.5 mAh g−1 at 0.5 C, which is far higher than of the pristine LiMn2O4 cathode (119.7 mAh g−1 at 1 C) and close to its theoretical capacity of 148.2 mAh g−1. After 1000 cycles, the capacity retention of the LMNO-0.025 sample reaches 56.53 % at 1 C, and it can be presented the higher capacity retentions of 66.79 % at 5 C and 66.89 % at 20 C. The robust structure stability proved by XRD, SEM and HRTEM data, and the good kinetics testified by CV and EIS data of the Ni-doped material are responsible to improve the high-rate capability and long cycle properties