Influence of Cr-Substitution on the Electrochemical Performance of LiNi0.5Mn0.5O2 Cathode Material for Lithium Ion Batteries

The cathode material LiNi0.5Mn0.5-xCrxO2 (x=0, 0.01, 0.02, 0.05, 0.1) was synthesized via a low temperature combustion process. The influence of the partial substitution of Cr for Mn on its electrochemical performance was investigated. Charge/discharge test results show that the partial substitution of Cr for Mn has a significant influence on the electrochemical performance of LiNi0.5Mn0.5-xCrxO2, and the proper amount substitution of Cr for Mn (x=0.02) can increase its discharge capacity and improve its cyclic stability. The X-ray diffraction (XRD) and Cycle Voltammetry (CV) analyses indicate that the proper amount substitution of Cr for Mn can suppress the cation mixing in the cathode material, reduce the electrochemical polarization of the electrode material and improve its reversibility. The discharge capacity of LiNi0.5Mn0.48Cr0.02O2 at 0.1 C between 2.5 and 4.6 V is 179.9 and 171.0 mAh/g in the 1st and the 50th cycle, respectively, with a capacity retention of 95.1%.