Efficient Access of Voltammetric Charge in Hybrid Supercapacitor Configured with Potassium Incorporated Nanographitic Structure Derived from Cotton (Gossypium arboreum) as Negative and Ni(OH)2/rGO Composite as Positive Electrode

Abstract

Potassium (K) incorporated nanographitic structure has been derived from cotton (Gossypium arboreum) through KOH activation followed by postannealing treatment. The outer active sites increase as compared to the inner active sites in consequence to K incorporation. Diffusion time constant also decreases as surface area increases after K incorporation. Electrical conductivity of the nanographitic structure increases with K incorporation and showed a high specific capacitance (∼431 F g–1) as negative electrode material. An asymmetric supercapacitor (ASC) has been configured where α-Ni(OH)2/reduced graphene oxide composite was used as the positive electrode material. Appropriate incorporation of the positive and negative electrode materials in the ASC is supported by the efficient (74%) access of voltammetric charge available by the individual electrodes. Furthermore, low relaxation time constant (∼150 ms), high energy density (∼111 W h kg–1), and long life stability of the ASC ensure its potentiality in the...