Construction of a surface heterosphere for a Li-rich manganese-based cathode with improved Li storage properties

Abstract

Lithium-rich, manganese-based cathode materials with high specific capacity have become a research focus in recent years; however, the transformation to the spinel phase and the dislocations of the material lead to inferior electrochemical performances. In this work, a lanthanum heterosphere was constructed on the surface of a Li-rich manganese-based material without distinct phase interface and lattice mismatch to address these problems. Such a surface heterosphere can prevent the migration of metal ions and enhance the diffusion of Li+ and transference of electrons. By virtue of the surface heterosphere, which can also preserve the oxygen vacancies, high initial discharge/charge capacities of La-LLO (359.6/293.4 mA h g−1) can also be achieved. The La-LLO cathode also exhibits outstanding cycle performance (236.7 mA h g−1 at 0.1 A g−1 during 100 cycles) and rate capability (59.3 mA h g−1 and the capacity retention of 76.9% for 500 cycles at 5 A g−1). It has been proven that such a melting impregnation method is effective in constructing a surface heterosphere on the surface of a Li-rich manganese-based material for improving Li storage properties.