Cycling performance of LiNiyMn2 − yO4 prepared by the solid-state reaction

In order to improve the cycling performance of LiMn2O4, a part of Mn in LiMn2O4 was replaced by Ni. LiNiyMn2 − yO4 (y = 0.02, 0.05, 0.10, 0.15, and 0.20) were synthesized by preheating a mixture of LiOH, MnO2 (CMD), and NiO at 400°C for 10 h and then calcining at 850°C for 48 h in air with intermediate grinding. The voltage vs. discharge capacity curves at a current density of 300 μA/cm2 between 3.5 and 4.3 V showed two plateaus, but the plateaus became unclear as the value of y increased. The sample with y = 0.02 had the largest first discharge capacity of 118.1 mA h/g. The LiNi0.10Mn1.90O4 sample had a relatively large first discharge capacity of 95.0 mA h/g and snowed an excellent cycling performance.