Mesoporous hybrid NiOx–MnOx nanoprisms for flexible solid-state asymmetric supercapacitors

Abstract

Mesoporous hybrid NiO_x–MnO_x nanoprisms have been successfully prepared in this work. The synthesis process involves a facile solvothermal method for preparation of Ni–Mn precursor particles and a subsequent annealing treatment. These mesoporous hybrid NiO_x–MnO_x nanoprisms have a high surface area of 101.6 m² g⁻¹. When evaluated as electrode materials in supercapacitors, the as-prepared mesoporous hybrid NiO_x–MnO_x nanoprisms deliver a specific capacitance of 1218 F g⁻¹ at a current density of 2.0 A g⁻¹. More importantly, the mesoporous hybrid NiO_x–MnO_x nanoprisms were successfully used to construct flexible solid-state asymmetric supercapacitors. The device shows a specific capacitance of 149.1 mF cm⁻² at 2.0 mA cm⁻², a good cycling stability with only 2.9% loss of capacitance after 5000 charge–discharge cycles, and good mechanical flexibility under different bending angles. These results support the promising application of mesoporous hybrid NiO_x–MnO_x nanoprisms as advanced supercapacitor materials.