Zr-doping stabilizes spinel LiMn ₂O ₄ as a low cost long cycle life cathode for lithium ion batteries

The present commercial spinel LiMn ₂O ₄ delivers only 90 mAh/g–115 mAh/g, far lower than the theoretical specific capacity. It degrades fast caused by the 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 LiMn ₂O ₄. Li _1.06Mn _{1.94– x} Zr _x O ₄ ( x = 0, 0.01, 0.02, 0.04) have been successfully synthesized by a simple solid-state reaction method and evaluated as cathode for lithium ion batteries (LIB). Li _1.06Mn _1.92Zr _0.02O ₄ is superior cathode material with a high capacity of 122 mAh/g at 1-C rate; long cycle stability, 98.39% retention after 100 cycles at 1-C rate, excellent high rate performance 107.1 mAh/g at 10-C rate, and high temperature performance 97.39% retention after 60 cycles. These are thought to be related to Zr doping effectively stabilizing the spinel LiMn ₂O ₄, by forming stronger Zr–O bonds in the octahedron, suppressing the Jahn–Teller effect, thus improving electrochemical performance.