Mn3O4 hollow microcubes and solid nanospheres derived from a metal formate framework for electrochemical capacitor applications

Abstract

Mn₃O₄ hollow microcubes and solid nanospheres were selectively fabricated from a metal formate framework ([CH₃NH₃][Mn(HCOO)₃]) by employing the ion exchange reaction in alkaline solution under different hydrothermal conditions. The relationships between Mn₃O₄ morphology and reaction molar ratio and reaction time were investigated. When used as the electrode materials for supercapacitors, Mn₃O₄ hollow microcubes and solid nanospheres had specific capacitances of 176 and 150 F g⁻¹ respectively at a current density of 0.3 A g⁻¹ in 1 M Na₂SO₄. The specific capacitance retentions of the Mn₃O₄ hollow microcubes and solid nanospheres were 95% and 86% respectively after 8000 charge–discharge cycles at a current density of 2 A g⁻¹. Electrochemical results show that the Mn₃O₄ hollow microcubes and solid nanospheres exhibit acceptable specific capacitance and excellent cycling stability.