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

Agraphene-Mn₃O₄-graphene (GMG) sandwich structure with homogeneous anchoring ofMn₃O₄ nanoparticles among flexible and conductive graphene nanosheets (GSs) is achieved through dispersion of the GSs inMn(NO₃)₂ solution and subsequent calcination.Mn₃O₄ nanoparticles are 50∼200 nmclusters consisting of 10∼ 20 nmprimary particles, and serve as spacers to prevent the restacking of the GSs. GSs provide a highly conductive network amongMn₃O₄ nanoparticles for effi-cient electron transfer and buffer any volume change during cycling. Due to the strong synergistic effect betweenMn₃O₄ and GSs, the capacity contributions from GSs andMn₃O₄ inGMGare much larger than capacities of pure GSs andMn₃O₄. Consequently, theGMGcomposite electrodes show excellent electrochemical properties for lithium ion battery applications, demonstrating a large reversible capacity of 750 mAh g.1 at 0.1 Cbased on the mass ofGMGwith no capacity fading after 100 cycles, and high rate abilities of 500 mAh g^-1 at 5 Cand 380 mAh g^-1 at 10 C.