Homemade‐CVD‐Engineered Hierarchical Zn–Ni Sulfide Heterostructured Electrodes for High‐Performance Supercapacitors

Abstract

The development of binder‐free hierarchical heterostructured electrodes with rapid charge transport and abundant electroactive sites is essential for next‐generation supercapacitors. Herein, a homemade chemical vapor deposition (homemade‐CVD) technique is employed to directly grow binder‐free hierarchical ZnS/NiS/Ni 3 S 2 electrodes on nickel foam without polymeric binders. Structural characterization using XRD, XPS, HRTEM, BET, and EDX confirms the formation of a multiphase heterostructure with an interconnected porous architecture and a high specific surface area (97.59 m 2 g − 1 ). The synergistic effects of hierarchical porosity and multiphase heterointerfaces enhance electrolyte accessibility, accelerate ion diffusion, and facilitate electron transport, resulting in superior electrochemical performance. The optimized electrode delivers an ultrahigh specific capacitance (4033 F g − 1 ) at 0.5 mV s − 1 , excellent rate capability, and 84% capacitance retention after 10,000 charge–discharge cycles at 10 A g − 1 . Dunn's kinetic analysis reveals the combined contributions of diffusion‐controlled and surface‐controlled charge‐storage mechanisms. An asymmetric supercapacitor assembled with the optimized electrode achieves a specific capacitance (1222 F g − 1 ), an energy density (34 Wh kg − 1 ) at power density of 218 W kg − 1 and 82% capacitance retention after 10,000 cycles. These findings demonstrate that homemade‐CVD provides a potentially scalable route for fabricating high‐performance hierarchical transition‐metal sulfide electrodes for advanced energy‐storage applications.