Facile Synthesis of Mn3O4 Nanoplates-Anchored Graphene Microspheres and Their Applications for Supercapacitors

We describe a facile synthesis of Mn 3 O 4 nanoplates (NPs)-anchored graphene microspheres (GSs) and their applications as electrode materials for supercapacitors. The use of GSs as substrate significantly improve the electrochemical performance of Mn 3 O 4 , which can be attributed to unique spherical structure of graphene and excellent stability and anti-reunion of Mn 3 O 4 NPs. The success of this synthesis depends on the in situ reduction of Mn cations by carbon from GSs under hydrothermal conditions. The resultant Mn 3 O 4 NPs with an average thickness of 37 nm were uniformly distributed on the surface of GSs. Material characterizations, including XRD, Raman, FTIR and XPS, have been performed to confirm their shape, composition and structure. As a positive material, the as-prepared Mn 3 O 4 NPs/GSs composites exhibited excellent electrochemical property in a three-electrode system. In particular, their specific capacitance reached as high as 317 F g −1 at a scan rate of 10 mV s −1 , and a remarkable stability (about 100% retention of its initial capacitance) was achieve after 4000 galvanostatic charge-discharge cycles at the current density of 2 A g −1 . Therefore, Mn 3 O 4 NPs/GSs can have been used as an electrode material for supercapacitors.