Supercapacitive performance of cobalt-loaded amorphous zeolite for energy storage applications

Co-loaded amorphous zeolite has been prepared, characterized and tested as an electrochemical supercapacitor. Amorphous zeolite (AZ) and H-amorphous zeolite were prepared using the steam assisted crystallization method; the H+ was added on AZ via ion exchange with NH4NO3 to evaluate the supercapacitive difference between AZ and H-AZ. Co was loaded into the AZ and H-AZ by the impregnation method to enhance the redox properties. The physico-chemical properties of the AZ, H-AZ, Co/AZ and Co/H-AZ were investigated using various analytical characterization techniques, namely X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), High Resolution Scanning Electron Microscopy (HRSEM), N2 physisorption and X-ray Photoelectron Spectroscopy (XPS). The materials were subsequently drop-cast into a Ni foam and evaluated for supercapacitive properties. Notably, the resulting electrode materials exhibit supercapacitive behaviour that is effective over a potential window from −0.1 to +0.7 V in a potassium hydroxide (1 M KOH) aqueous electrolyte. A relatively high specific capacitance of 550 F/g at 1 A/g was calculated from Galvanometric Charge Discharge (GCD) analysis for the Co/H-AZ electrode with a Coulombic efficiency of 98% after 2000 cycles and a capacitance retention of 91.6%, while the value calculated for Co/AZ was 400 F/g with a Coulombic efficiency of 96% after 2000 cycles and a capacitance retention of 75.5%. The energy density and power density for Co/H-AZ were 19.09 W h/kg and 250 W/kg respectively, while the energy density and power density for Co/AZ were 13.88 W/kg and 248 W h/kg respectively. The difference in the performance of Co/H-AZ and Co/AZ can be attributed to the effect of H+ ions at the electrode/electrolyte interface. [Display omitted] •Amorphous zeolite (AZ) was synthesized by the steam-assisted method; H was ion exchanged into AZ.•Co was loaded onto the AZ and H-AZ and then drop cast onto Ni-foam.•Specific capacitance of Co/H-AZ and the Co/AZ: 550 and 400 F/g respectively.•After 2000 cycles, Co/H-AZ exhibited 98% Coulombic efficiency and 91.6 of capacitance retention.•Supercapacitor properties of Co/H-AZ are due to redox nature of Co3O4 and H+ in AZ.