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 N 2 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 5 h, it transforms into spinel nickel manganese oxide (NiMn 2 O 4 (300)) with a mesoporous structure, and the specific surface area is 201 m 2  g −1 and the pore size is around 8–10 nm. The electrochemical properties are characterized by cyclic voltammetry in 1 mol L −1 Na 2 SO 4 electrolyte. The prepared NiMn 2 O 4 (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 243 F g −1 at a low scan rate (5 mV s −1 ), and a specific capacitance of 169 F g −1 is obtained and the initial capacitance value of 96% can be maintained after 5000 cycles of the operation at the scan rate of 20 mV s −1 .