Preparation of NiMn2O4 with large specific surface area from an epoxide-driven sol−gel process and its capacitance

Abstract

Spinel nickel manganese oxide with large specific surface area and suitable pore size has been prepared from an epoxide-driven sol−gel process and followed by calcining treatment. The structural evolution of the samples obtained at different stages has been characterized by XRD, TEM, XPS, IR and N2 adsorption–desorption. The nickel manganese oxide aerogel is firstly obtained and propylene oxide plays an important role in its formation. The nickel manganese oxide aerogel is calcined at 300°C for 5h, it transforms into spinel nickel manganese oxide (NiMn2O4 (300)) with a mesoporous structure, and the specific surface area is 201m2g−1 and the pore size is around 8–10nm. The electrochemical properties are characterized by cyclic voltammetry in 1molL−1 Na2SO4 electrolyte. The prepared NiMn2O4 (300) material not only exhibits an ideal capacitive behavior, but also shows good cycling stability in a neutral electrolyte system. The value of specific capacitance reaches as high as 243Fg−1 at a low scan rate (5mVs−1), and a specific capacitance of 169Fg−1 is obtained and the initial capacitance value of 96% can be maintained after 5000 cycles of the operation at the scan rate of 20mVs−1.