The Synergetic Effect of LiMg 0.5 Mn 1.5 O 4 Coating and Mg 2+ Doping on Improving Electrochemical Performances of High‐Voltage LiNi 0.5 Mn 1.5 O 4 by Sol‐Gel Self‐Combustion Method

The composites of LiNi 0.5 Mn 1.5 O 4 (LNMO) modified with LiMg 0.5 Mn 1.5 O 4 (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 Mg 2+ 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 °C and 90.4% for 100 cycles at 55 °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 Mg 2+ doping could alleviate the impedance rise.