Synthesis and electrochemical properties of spinel LiMn2O4 derived from high-purity spherical Mn3O4

Abstract

Spinel LiMn₂O₄ has been regarded as one of the most promising cathode materials due to its low cost, environmental friendliness, high thermal stability and safety. However, the issues such as manganese dissolution and Jahn–Teller effect result in significant capacity degradation during long high-temperature cycling, limiting its large-scale application. In this study, we develop a novel metal manganese corrosion-oxidation method to fabricate high-purity spherical Mn₃O₄, which is then employed as the superior manganese source for the synthesis of spinel LiMn₂O₄ via high-temperature solid-state process. Moreover, the effects of different lithium sources and mole ratios of lithium to manganese on the structure and electrochemical performance of LiMn₂O₄ are investigated. It was found that the obtained LiMn₂O₄ exhibits excellent electrochemical performance by using lithium carbonate as the lithium source with a lithium to manganese ratio of 0.53. The discharge capacities at 1 C and 10 C are 124.9 and 106.0 mAh/g, respectively, and the capacity retention after 200 cycles at 1 C is 93.7%. These excellent properties are attributed to the high-purity and spherical morphology of the Mn₃O₄ precursor, which dramatically improves the structural stability and electrochemical kinetics of LiMn₂O₄. This work provides a straightforward and cost-effective pathway for the large-scale industrial production of high-performance spinel LiMn₂O₄ cathode materials for lithium-ion batteries.