The Synergetic Effect of LiMg0.5Mn1.5O4 Coating and Mg2+ Doping on Improving Electrochemical Performances of High-Voltage LiNi0.5Mn1.5O4 by Sol-Gel Self-Combustion Method

The composites of LiNi0.5Mn1.5O4 (LNMO) modified with LiMg0.5Mn1.5O4 (LMgMO) named LNMO@LMgMO as cathode materials for lithium ion battery that can withstand high voltage and high temperature were prepared by a sol-gel self-combustion method. The results of physical characterization show that the LMgMO layer was effectively coated on the surface of LNMO, and the Mg2+ was also doped into the lattice of LNMO. Electrochemical tests reveal that the LNMO@LMgMO composites deliver excellent electrochemical performance, especially for LNMO@LMgMO-1%, including great capacity retention (91.4% for 500 cycles at 25 degrees C and 90.4% for 100 cycles at 55 degrees C at 2 C in the 3.5-5.2 V) and superior rate capability (95.6 mAh g(-1) under 10 C). Moreover, the synergetic effect of LMgMO coating and Mg2+ doping could alleviate the impedance rise.