Synthesis And Electrochemical Performance Of Mn₃O₄ For Supercapacitor Electrode

Micro/nano-structured Mn3O4 with an open three-dimensional flowerlike morphology were fabricated by a facile solvothermal approach using hexadecyltrimethylammonium bromide used as surfactant and CH3CH2 OH used as solvent. The structure and electrochemical properties of the materials were investigated by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Field emission scanning electron microscopic(FE-SEM), Transmission electron microscopy(TEM) and Electrochemical impedance spectroscopy(EIS).The Mn3O4 microspheres are self-assembled by one-dimensional nanowires, and also, a dandelion-structure formation mechanism of the Mn3O4 microspheres is discussed as well. The Mn3O4 microspheres used as supercapacitor electrode in 1 mol L-1 Na2SO4 electrolyte have a specific capacitance value of 286 F g-1 at a low current density of 0.5 A g-1, and can still retain 80%(230 F g-1) and 73%(210 F g-1) when the current densities are increased by 10 times(5 A g-1) and 20 times(10 A g-1), respectively. In addition, the capacitance retention is 90% after 1000 cycles at a current density of 5 A g-1. In comparison with the Mn3O4 synthesized in N,N-dimethylformamide solvent, the micro/nano-structured Mn3O4 used as a supercapacitor electrode exhibits larger interface of the electrode and electrolyte; higher electrolyte penetration/diffusion rates and larger volumetric energy density.