Flowery nickel-cobalt hydroxide via a solid-liquid sulphur ion grafting route and its application in hybrid supercapacitive storage.

ABSTRACT: In our research, a two-step solid-liquid route was employed to fabricate flowery nickel-cobalt hydroxide with sulphur ion grafting (Ni1Co2-S). The utilization of NaOH/agar and Na₂S/agar could efficiently retard the release rates of OH^- or S^2- ions at the solid-liquid interface due to strong bonding between agar hydrogel and these anions. Ni1Co2-S generally displays ultrathin flowery micro-frame, ultrathin internal nanosheets and expanded pore size. Besides, the introduction of suitable sulphide species into nickel-cobalt hydroxide could improve its conductivity due to the lower band gap of Ni-Co sulphide. The supercapacitive electrode Ni1Co2-S presented capacitance of 1317.8 F g^-1 (at 1 A g^-1) and suitable rate performance (77.9% at 10 A g^-1 and 59.3% at 20 A g^-1). Furthermore, a hybrid supercapacitor (HSC) was developed utilizing positive Ni1Co2-S and negative activated carbon electrodes. As expected, the HSC device exhibited excellent specific capacitance (117.1 F g^-1 at 1 A g^-1), considerable energy densities (46.7 W h kg^-1 at 0.845 kW kg^-1 and 27.5 W h kg^-1 even at 9 kW kg^-1) and suitable cycling performance, which further illuminated the high energy storage capacity of Ni1Co2-S.

SUBMITTER: Ye L 

PROVIDER: S-EPMC9081773 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature