Synthesis and electrochemical characteristics of LiCrxNi0.5−xMn1.5O4 spinel as 5 V cathode materials for lithium secondary batteries

A series of electrochemical spinel compounds, LiCrxNi0.5−xMn1.5O4 (x=0, 0.1, 0.3), are synthesized by a sol–gel method and their electrochemical properties are characterized in the voltage range of 3.5–5.2 V. Electrochemical data for LiCrxNi0.5−xMn1.5O4 electrodes show two reversible plateaus at 4.9 and 4.7 V. The 4.9 V plateau is related to the oxidation of chromium while the 4.7 V plateau is ascribed to the oxidation of nickel. The LiCr0.1Ni0.4Mn1.5O4 electrode delivers a high initial capacity of 152 mAh g−1 with excellent cycleability. The excellent capacity retention of the LiCr0.1Ni0.4Mn1.5O4 electrode is largely attributed to structural stabilization which results from co-doping (chromium and nickel) and increased theoretical capacity due to substitution of chromium.