Low-temperature synthesis of Na2Mn5O10 for supercapacitor applications

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