High Performance LiMn₂O₄ Cathode Materials Grown with Epitaxial Layered Nanostructure for Li-Ion Batteries

Abstract

Tremendous research works have been done to develop better cathode materials for a large scale battery to be used for electric vehicles (EVs). Spinel LiMn₂O₄ has been considered as the most promising cathode among the many candidates due to its advantages of high thermal stability, low cost, abundance, and environmental affinity. However, it still suffers from the surface dissolution of manganese in the electrolyte at elevated temperature, especially above 60 °C, which leads to a severe capacity fading. To overcome this barrier, we here report an imaginative material design; a novel heterostructure LiMn₂O₄ with epitaxially grown layered (<i>R</i>3̅<i>m</i>) surface phase. No defect was observed at the interface between the host spinel and layered surface phase, which provides an efficient path for the ionic and electronic mobility. In addition, the layered surface phase protects the host spinel from being directly exposed to the highly active electrolyte at 60 °C. The unique characteristics of the heterostructure LiMn₂O₄ phase exhibited a discharge capacity of 123 mAh g^–1 and retained 85% of its initial capacity at the elevated temperature (60 °C) after 100 cycles