Design of pseudocapacitance and amorphization Co-enhanced Mn3O4/graphene sheets nanocomposites for high-performance lithium storage

Abstract Mn3O4-based materials have been broadly investigated as anode materials for lithium- ion batteries (LIBs) due to their high energy densities, affordable cost, environmental benignity, etc. However, the wide voltage hysteresis due to inferior electronic conductivity and serious volume expansion during lithiation/delithiation seriously restricted their practical applications. In this work, Mn3O4/graphene sheet (MGS) nanocomposites were prepared by a solution reaction assisted calcination method, which led to superior electrochemical performance for LIBs and presented both high reversible capacity and excellent cyclic stability (1199.5 mAh g−1 after 600 cycles and 995.3 mAh g−1 after 1000 cycles at a current density of 500 mA g−1). The superior cyclic stability could be attributed to the amorphization effect of Mn3O4 and strong coupling interaction between Mn3O4 and graphene sheets. On one hand, the highly oxidized Mn3O4 and increasing Li+ active sites during extended cycles are beneficial to achieve high specific capacity. Meanwhile, the strong coupling effect, fast pseudocapacitive reaction and amorphous phase effect help provide numerous voids, which effectively alleviate volume expansion and enable excellent cyclic stability, enriching their great opportunities for LIBs anode materials with narrow voltage hysteresis and long cycle life.