Element substitution of a spinel LiMn2O4 cathode

Abstract

Spinel LiMn₂O₄ is a promising cathode material for lithium-ion batteries ascribed to its steady bulk structure and abundant manganese sources. Nevertheless, severe capacity decay due to the Jahn–Teller effect and spontaneous disproportionation reaction seriously hampers its extensive application, especially at high-temperature or high-potential operation circumstances. Attributed to the strengthening of the crystallographic structure and the inhibition of Mn³⁺ side reactions, element substitution has become one of the most momentous tactics in the modification of LiMn₂O₄. Here, we comprehensively review the developments on restraining capacity fading and enhancing the performances of LiMn₂O₄ through element substitution. Primarily, the capacity fading mechanism of LiMn₂O₄ has been thoroughly recapitulated. Subsequently, our summary is proposed based on two categories, which are phase evolution and solid solution strengthening invoked by element substitution, and the latter can be subdivided into structure strengthening and Li⁺ diffusion kinetics boosting. More importantly, we put forward a methodological approach for future element substitution research studies. This report will shed light on the future direction of LiMn₂O₄ cathode material optimization.