Strategies for improving the cyclability and thermo-stability of LiMn2O4-based batteries at elevated temperatures

Abstract

Lithium manganese oxide (LiMn₂O₄) is one of the most suitable cathode materials for widespread large-scale applications of lithium ion batteries due to its advantages of high thermal stability, guaranteed safety, low cost, environmental friendliness, relatively good power density and acceptable energy density. However, LiMn₂O₄-based batteries with LiPF₆-based carbonate electrolytes always suffer from severe capacity deterioration and poor thermostability, especially at elevated temperatures. Hence, it is necessary to systematically and comprehensively summarize the progress in understanding and modifying LiMn₂O₄-based batteries from various aspects. In this review, different reported possible fading mechanisms of LiMn₂O₄-based batteries are first discussed in detail. Then, the various proposed strategies to improve the cyclability and thermostability of LiMn₂O₄-based batteries at elevated temperatures, including electrolyte optimization, element doping, surface coating, development of functional separators/gel electrolytes and binders, control of special morphologies etc., are covered. Finally, several perspectives are summarized based on the elaborated progress and our own experimental evaluations, aiming to provide some possible attractive strategies and research directions for future upgrading of LiMn₂O₄-based batteries with improved high temperature performances.