Fig. 6. (a) Galvanostatic CDC curves of all electrodes (applied current: 1 mA), (b) CDC curves of rGO:CB electrode under different currents, (c) CDC curves of NirGO3 electrode under different currents, (d) specific capacitance (F g─1) vs. discharge current (1-5 A g─1) and (e) energy density (Wh kg─1) vs. power density (W kg─1) plots for all electrodes.
Conclusion
Composite electrodes with three Ni/rGO ratios were made without a binder in one step. The structural characterisation of NirGO1, NirGO3, and NirGO6 electrodes revealed that the nickel metal present in the electrodes, α-Ni(OH)2, demonstrated improved capacitive behavior. The study found that the capacitance values of binder-free NirGO1, NirGO3, and NirGO6 were 720, 800, and 310 F g─1 respectively in 1M H2SO4 electrode solution using a three-electrode method. Unlike the reference electrode rGO:CB, its capacitance value was computed as 900 F g─1. According to capacitance tests NirGO3 current decay was less than rGO:CB owing to homogeneous pore structure of NirGO3.