MnO2 nanoflakes anchored on reduced graphene oxide nanosheets as high performance anode materials for lithium-ion batteries

A MnO2 nanoflake-reduced graphene oxide (MnO2-rGO) composite was synthesized by a facile solution method. The composite exhibited excellent electrochemical performance with a reversible capacity of 1430 mA h g(-1) and 520 mA h g(-1) at current densities of 0.1 A g(-1) and 10 A g(-1), respectively. MnO2 in the composite was proved to be fully activated and went through a complete conversion reaction. The improved kinetics in the MnO2-rGO composite electrode were evidenced by Electrochemical Impedance Spectroscopy (EIS) results, accounting for its extraordinary electrochemical properties compared with that in a simple MnO2-rGO mixture electrode. Due to the uniform dispersion and firm anchoring of MnO2 nanoflakes on the rGO surface, the volume expansion of MnO2 during the charge-discharge process was significantly alleviated. It showed excellent cyclic performance with an extremely large capacity of 1000 mA h g(-1) maintained after 200 cycles at the current density of 1 A g(-1).