Low-temperature synthesis of Na2Mn5O10 for supercapacitor applications

The romanechite-like sodium manganese oxide Na2Mn5O10 is synthesized through alkaline hydrolysis of [Mn12O12(CH3COO)16(H2O)4] followed by thermal calcination. Amorphous Na2Mn5O10 is obtained at relatively low temperature (200 °C). Increasing the calcination temperature leads to highly crystalline nano-rods. Electrochemical studies demonstrate that Na2Mn5O10 is a good candidate as positive electrode materials for supercapacitor: specific capacitances of 178, 173 and 175 F g−1 are obtained for Na2Mn5O10 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%.

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► Na2Mn5O10 is synthesized using dodeca-nuclear mixed valence manganese oxo-clusters as precursor at low temperature.
► Na2Mn5O10 shows good supercapacitor properties.
► Distinct supercapacitive behaviors are observed between amorphous and crystalline samples.