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

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 degrees C for 5h, it transforms into spinel nickel manganese oxide (NiMn2O4 (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 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 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 my s(-1). (C) 2012 Elsevier Ltd. All rights reserved.