Synergistic effect of manganese oxide nanoparticles and graphene nanosheets in composite anodes for lithium ion batteries

Abstract

A graphene-Mn3O4-graphene (GMG) sandwich structure with homogeneous anchoring of Mn3O4 nanoparticles among flexible and conductive graphene nanosheets (GSs) is achieved through dispersion of the GSs in Mn(NO3)2 solution and subsequent calcination. Mn3O4 nanoparticles are 50 ∼ 200 nm clusters consisting of 10 ∼ 20 nm primary particles, and serve as spacers to prevent the re-stacking of the GSs. GSs provide a highly conductive network among Mn3O4 nanoparticles for efficient electron transfer and buffer any volume change during cycling. Due to the strong synergistic effect between Mn3O4 and GSs, the capacity contributions from GSs and Mn3O4 in GMG are much larger than capacities of pure GSs and Mn3O4. Consequently, the GMG composite electrodes show excellent electrochemical properties for lithium ion battery applications, demonstrating a large reversible capacity of 750 mAh g−1 at 0.1 C based on the mass of GMG with no capacity fading after 100 cycles, and high rate abilities of 500 mAh g−1 at 5 C and 380 mAh g−1 at 10 C.