Self-supported NiCo2O4@Ni1.18S core-shell nanocomposite with impressive electrochemical properties suitable for hybrid supercapacitors

Self-supported NiCo2O4@Ni1.18S core-shell nanocomposite were synthesized on nickel foams by uniform growth Ni1.18S nanosheets encircling NiCo2O4 nanoneedles. Characterization results demonstrate that NiCo2O4@Ni1.18S core-shell nanocomposite have significant advantages in one - and two-dimensional nanostructure coordination structure, with richer REDOX active sites and more energy storage paths. Density functional theory (DFT) calculations results indicate that the surficial adsorption energy with OH- ions is enhanced in NiCo2O4@ Ni1.18S nanocomposite, thereby facilitating the reversible redox reaction kinetics and the electrochemical activity. As a result, self-supported NiCo2O4@Ni1.18S core-shell nanocomposite exhibit excellent energy-storage properties, i. e.: the specific charge capacity of 3158 F g- 1 at 1 A g- 1, high rate performance of 52.3 % from 1 A g- 1 to 5 A g- 1, and the 81.25 % capacity retention rate after 5000 cycles. Especially, it should be pointed out that the hybrid supercapacitors assembled from self-supported NiCo2O4@Ni1.18S core-shell nanocomposite and activated carbon present the wide voltage window (0-1.6 V), high energy density of 100.3 Wh kg- 1 at power density of 177 W kg- 1 and prospective commercial consideration. These facts fully prove the practical feasibility of self-supported NiCo2O4@Ni1.18S core-shell nanocomposite in advanced energy-storage facilities.