Boosting redox activity and charge transfer kinetics in hollow CoNiS/CoNi-LDH heterostructures via interface engineering for high-performance supercapacitors

Abstract

Herein, we report a rational design of hollow CoNiS/CoNi-LDH heterostructures via partial sulfurization of ZIF-67-derived CoNi-LDH, which acts as a self-sacrificing template. The controlled partial phase transformation from CoNi-LDH to CoNiS creates an interfacial charge redistribution between the CoNiS and CoNi-LDH components, which synergistically enhances the redox activity and charge transfer kinetics, with a 15.2-fold decrease (from 6.70 Ω to 0.44 Ω) in the charge transfer resistance compared with that of pristine CoNi-LDH, thereby increasing the pseudocapacitive charge storage capacity. Furthermore, the hierarchical hollow architecture coupled with the superhydrophilic surface facilitates rapid electrolyte infiltration, shortening ion diffusion pathways. As a result, the optimized heterostructure delivers a remarkable specific capacitance of 1094 F g⁻¹ at 1 A g⁻¹ in a three-electrode system and achieves a remarkable energy density of 44 Wh kg⁻¹ at 800 W kg⁻¹ when integrated into asymmetric supercapacitors, highlighting the advantages of interface-dominated heterostructure engineering as a universal strategy for overcoming the intrinsic limitations of LDH-based supercapacitors.