Space-confinement of MnO nanosheets in densely stacked graphene: Ultra-high volumetric capacity and rate performance for lithium-ion batteries

The requirements on volumetric and gravimetric performances of lithium-ion batteries have been more and more urgent for their applications in miniaturized consumer electronics. Herein, we report a simple synthesis strategy of densely stacked graphene/MnO architecture anode for lithium-ion batteries. Through a simply modified Hummers method, the MnO2 nanofibers are homogeneously confined in-between the graphene oxide sheets, which can form a three-dimensional layered dense structure that can be easily reduced to densely stacked graphene/MnO architecture during annealing process. More importantly, the integration of MnO nanosheets and graphene sheets with dense architecture is beneficial for the enhanced electron/ion transfer kinetics, and the improved structural and interfacial stability during charge-discharge process. As a result, the graphene/MnO architecture electrode exhibits ultra-high gravimetric/volumetric capacities (1000 mA h g(-1)/2288 mA h cm(-3) at 0.1 A g(-1)), excellent rate performance (270 mA h g(-1)/618 mA h cm(-3) at 8.0 A g(-1)), ultra-low volume expansion (18%) and outstanding cycling stability (118% of capacity retention after 300 cycles).