Zn-Y co-doped LiNi0.5Mn1.5O4 cathode materials with high electrochemical performance

The LiNi0.5−xZnxMn1.48Y0.02O4 (x = 0.01, 0.03, 0.05) series were prepared via a sol-gel method. The mechanism of the Zn2+ and Y3+ co-doping on the structural morphology and Mn3+ ion dissolution, which led to the improved electrochemical performance of the LiNi0.5Mn1.5O4 (LNMO) sample, were studied. Compared with the pristine LNMO, Zn-Y co-doping led to increased lattice parameters, morphological evolution, decreased Mn3+ content, and better electrochemical properties. Among all the samples, LiNi0.47Zn0.03Mn1.48Y0.02O4 (0.03ZnY) showed optimal electrochemical properties at room temperature and elevated temperature. After 200 cycles, the 0.03ZnY sample showed excellent cycling performance, i.e., 134.529 mAh g−1 at 1 C (with a capacity retention of 94.7%), which was higher than the pristine sample (104.913 mAh g−1, with a capacity retention of 92.7%). Furthermore, when tested at 1 C, at a high temperature (55 °C), the 2.03Zn-Y sample reached a discharge capacity of 94.004 mAh g−1 and maintained a 79.6% capacity retention after 120 cycles, which was higher than the pristine sample (52.430 mAh g−1, 43.6% capacity retention).