Zr-doping stabilizes spinel LiMn₂O₄ as a low cost long cycle life cathode for lithium ion batteries

Abstract

The present commercial Spinel LiMn2O4 delivers only 90-115 mAh/g, far lower than the theoretical specific capacity, and degrades fast caused by Jahn-Teller effect, Mn dissolution and related side reactions that consume Li inventory. In this work, Zr doping is employed to improve the structural stability and electrochemical performance of spinel LiMn2O4. Li1.06Mn1.94-xZrxO4 (x = 0, 0.01, 0.02, 0.04) have been successfully synthesized by simple solid state reaction method and evaluated as cathode for Lithium ion batteries (LIB). Li1.06Mn1.92Zr0.02O4 is superior cathode material with high capacity 122 mAh/g at 1C rate; long cycle stability, 98.39% retention after 100 cycles at 1C rate, excellent high rate performance 107.1 mAh/g at 10C rate, and high temperature performance 97.39% retention after 60 cycles. These are thought to be related to Zr doping effectively stabilizes the spinel LiMn2O4, by forming stronger Zr-O bonds in the octahedron, suppressing Jahn-Teller effect, thus improves electrochemical performance.