Enhanced Electrochemical Performance of 5V LiNi0.5Mn1.5‐xZrxO4 Cathode Material for Lithium‐Ion Batteries

Abstract

AbstractSeries of LiNi0.5Mn1.5‐xZrxO4 (x=0, 0.0025, 0.005, 0.01, 0.02) samples have been prepared by a combined coprecipitation‐hydrothermal method followed by two‐step calcination. The effects of Zr4+ doping contents on the structure, morphology and electrochemical properties are studied. The results show that Zr4+ doping reduces Mn3+ content and Ni/Mn disordering degree. Additionally, Zr4+ doping reduces primary particle size and agglomeration degree. More significantly, Zr4+ doping leads to the appearance of higher‐surface‐energy {110} and/or {311} facets, while undoped sample only consists of {111} and {100} facets. But excessive Zr4+ doping (x=0.02) leads to the decrease of higher‐surface‐energy facets. Electrochemical results show that appropriate Zr4+ doping improves the rate and cycling performances of LiNi0.5Mn1.5O4 material. Among them, LiNi0.5Mn1.495Zr0.005O4 shows the optimal electrochemical performance, which can be attributed to high phase purity, high crystallinity, appropriate primary particle size and agglomeration degree, enlarged lattice constant, and greater exposure of {110} and/or {311} facets.