Mn3O4/reduced graphene oxide based supercapacitor with ultra-long cycling performance

In this work, highly stable Mn3O4 nanoparticles were synthesized via an air oxidation procedure with the aid of an anionic surfactant, which showed durable performance with 100% capacitance retention after 10 000 cycles in 1 M Na2SO4. An annealed film was subsequently fabricated in which the nanostructured Mn3O4 was uniformly intercalated between reduced graphene oxide (RGO) sheets. To complement the Mn3O4/RGO film, a hybrid film consisting of RGO and carbon nanotubes was employed as the negative electrode. Benefiting from the thermodynamically stable Mn3O4 nanoparticles, specific layered structural design, and highly conductive RGO scaffolds, the assembled supercapacitor exhibited a high volumetric capacitance of 52.2 F cm(-3) at 0.2 A cm(-3), which translated to remarkable volumetric energy and power density (18 mW h cm(-3) and 3.13 W cm(-3)). More importantly, the assembled device was able to demonstrate an outstanding cycling performance of 115% capacitance retention after 60 000 cycles. The bottom-up approach proposed in this study involving the synthesis of durable nanoparticles followed by composite construction could pave the way towards designing ultra-stable supercapacitors as next-generation energy storage devices.