Fabrication and electrochemical performance of sodium manganese oxide composite for supercapacitor application

In this work, an alkali metal cation doped transition metal oxide namely, sodium manganese oxide (NMO) was synthesized by a simple solid state calcination method. The structure, functional group, morphology and elemental composition of the prepared NMO were characterised using XRD, FTIR, SEM-EDAX, TEM and XPS. The electrochemical performance was analysed by CV, GCD and EIS. The specific capacitance of NMO was found to be 151 F/g at a current density of 1 A/g. To enhance the specific capacitance of the synthesised material, CNT was added to NMO and a comparison on the electrochemical studies of NMO/SWCNT and NMO/MWCNT was done. The results show that the NMO/MWCNT exhibits a high specific capacitance of 415 F/g at a current density of 1 A/g with a good rate performance and attains an excellent electrochemical stability of 99% initial capacitance retention and coulombic efficiency of 101% with 10,000 cycles at a current density of 5 A/g. As a whole, these positive results make NMO/MWCNT, as a promising electrode material for supercapacitor. Graphical abstract