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.