Enhanced cycling stability of spinel LiMn2O4 cathode by incorporating graphene sheets

LiMn2O4-graphene nanocomposites with different weight ratios of LiMn2O4/graphene were successfully prepared via a simple method by ball-milling of commercially available LiMn2O4 particles and graphene nanosheets. Experimental results revealed that the spinel LiMn2O4 particles within the as-prepared LiMn2O4-graphene nanocomposites were well distributed onto the flexible graphene sheets, and the nano-composites with a higher graphene content were favorable to form more uniform composite materials. Compared to the pristine spinel LiMn2O4 particles, the as-prepared LiMn2O4-graphene nanocomposites exhibited lower initial discharge capacities owing to the reduced amount of active materials (LiMn2O4 particles) in the nanocomposites. However, their electrochemical cycling performance was significantly enhanced, high-lighting the advantages of anchoring LiMn2O4 particles on graphene sheets. The enhanced cycling performance could be ascribed to the fact that the graphene nanosheets within the LiMn2O4-graphene nanocomposites could provide a 3D conducting scaffold, which could not only alleviate the aggregation of LiMn2O4 particles and accommodate the volume changes of LiMn2O4 particles, but also enhance the ionic conductivity and charge transfer during the lithiation/delifhiation process.