Synthesis of micro/nano-structured Mn3O4 for supercapacitor electrode with excellent rate performance

Abstract

Micro/nano-structured Mn₃O₄ with an open three-dimensional flower-like morphology were fabricated by a facile solvothermal approach using hexadecyltrimethylammonium bromide as a surfactant and CH₃CH₂OH as a solvent. The Mn₃O₄ microspheres were self-assembled by one-dimensional nanowires; in addition, a dandelion-structure formation mechanism of the Mn₃O₄ microspheres is discussed. The Mn₃O₄ microspheres used as a 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% specific capacitance (210 F g⁻¹) when the current densities are increased ten-fold (5 A g⁻¹) and twenty-fold (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 Mn₃O₄ synthesized in N,N-dimethylformamide solvent at 0.5 A g⁻¹ and 5 A g⁻¹, the specific capacitance obtained increased by 18.7% and 17.4%, respectively.