Three-dimensional interconnected composite nanoarchitectonics with Ni(OH)2/Ni3S2 nanosheets and hierarchical porous carbon for high-performance supercapacitor electrodes

Abstract

This study proposes a pseudocapacitive modification method for biomass-derived carbon materials based on the electrochemical deposition of NiCl₂•6H₂O and thiourea, successfully preparing a three-dimensional interconnected composite of Ni(OH)₂/Ni₃S₂ nanosheets and hierarchical porous carbon. By utilizing electrochemical deposition technology, Ni(OH)₂ with high theoretical capacity and Ni₃S₂ nanosheets with high conductivity were uniformly loaded onto the surface of hierarchical porous carbon, achieving a synergistic enhancement effect of bimetallic active phases. Research indicates that the Ni(OH)₂/Ni₃S₂-GSN-20 prepared after 20 mins of deposition forms a three-dimensional microspherical structure composed of interconnected Ni(OH)₂ and Ni₃S₂ nanosheets, significantly enhancing the contact area and transport efficiency of electrolyte ions. Ni(OH)₂ and Ni₃S₂ exhibit notable pseudocapacitive effects through reversible redox reactions, while the carbon matrix contributes to the stability of double-layer capacitance. As a supercapacitor electrode material, Ni(OH)₂/Ni₃S₂-GSN-20 demonstrates a specific capacitance of 571.1 F g⁻¹ at 0.5 A g⁻¹ in a three-electrode system. The asymmetric supercapacitor assembled with Ni(OH)₂/Ni₃S₂-GSN-20 as the positive electrode and GSN as the negative electrode exhibits excellent cycling stability in 6 M KOH electrolyte, achieving an energy density of 10.02 W h kg⁻¹ and a power density of 833.07 W kg⁻¹ at 1 A g⁻¹. This study provides new insights into the design of high-performance supercapacitor electrode materials while realizing the high-value utilization of biomass resources.