Low-temperature synthesis of Na sub(2Mn) sub(5)O sub(10 for supercapacitor applications)

The romanechite-like sodium manganese oxide Na sub(2Mn) sub(5)O sub(10 is synthesized through alkaline hydrolysis of [Mn) sub(1)2O sub(12(CH) sub(3)COO) sub(16(H) sub(2)O) sub(4] followed by thermal calcination. Amorphous Na) sub(2)Mn sub(5O) sub(1)0 is obtained at relatively low temperature (200 degree C). Increasing the calcination temperature leads to highly crystalline nano-rods. Electrochemical studies demonstrate that Na sub(2Mn) sub(5)O sub(10 is a good candidate as positive electrode materials for supercapacitor: specific capacitances of 178, 173 and 175 F g) super(-)1 are obtained for Na sub(2Mn) sub(5)O sub(10 calcined at different temperatures (200, 400 and 600 degree C), respectively, by charge-discharge tests at 0.1 A g) super(-)1. Moreover, capacitance losses of all the products in 1000 cycles are less than 3%.