Construction of sulfide nanoparticles on hydrangea-like nickel‑cobalt hydroxide for enhanced pseudocapacitance

Abstract

Transition metal hydroxides have been extensively studied due to their high theoretical capacity. However, poor electrical conductivity and limited active sites hinder further practical applications. Therefore, in this work, hydrangea-like NiCo-LDH(Layered double hydroxide) precursor was synthesized by hydrothermal method. Based on this precursor, sulfide nanoparticles were constructed on NiCo-LDH nanosheets through an ion-exchange strategy. Sulfide nanoparticles with high electrical conductivity are grown in NiCo-LDH nanosheets, and the construction of heterojunctions between NiCo-LDH and sulfide nanoparticles enables them to provide ion or electron transport paths to each other, significantly improving electrode materials conductivity. Also, the close contact between the nanoparticles and LDH provides additional active sites. Significant synergy between nanoparticles and LDH, which contributes to improved electrochemical performance. By adjusting the amount of thioacetamide added, the optimized NC/S-15(Means added 15 mg thioacetamide for NiCo-LDH)material(267.8 mAh g−1 at 1A g−1) showed better specific capacity than NiCo-LDH. Assembled hybrid supercapacitor (HSC) using NC/S-15 nanomaterials as cathode and activated carbon (AC) as anode with high specific capacitance of 126.76 F g−1 at 1 A g−1 and reasonable energy and power density (43.6 Wh kg−1 at 375 W kg−1) as well as excellent capacitance retention (83 % after 5000 cycles).