A MoS2-templated oxidation-etching strategy to synthesize hollow δ-MnO2 nanospheres as a high-performance electrode for supercapacitor

Hollow delta-MnO2 nanospheres have been synthesized through an in situ redox etching reaction using MoS2 nanospheres as a sacrificial template in a KMnO4 aqueous solution. The formation mechanism for hollow delta-MnO2 nanospheres was investigated through designing the time-dependent experiments on the hydrothermal redox etching reaction. Based on the advantages of hollow structure, hollow delta-MnO2 nanospheres as an electrode for supercapacitors demonstrated a high specific capacitance of 394 F g(-1) at 1 A g(-1) and good cycle stability with 95.2% capacitance retention after 5000 cycles at 5 A g(-1). Furthermore, an asymmetric supercapacitor device was assembled using hollow delta-MnO2 nanospheres as the positive electrode, which delivered an energy density of 24.4 W h kg(-1) at a power density of 999 W kg(-1). These findings suggest a great promise for hollow delta-mnO(2) nanospheres in high-performance supercapacitors.