Introducing S in the interface to build S-bridged core-shell electrode Ni(OH)₂-S/ZIF-67 with high electrochemical performance

Strengthening interfacial interactions is critical for improving the electrochemical properties of composite electrodes and advancing supercapacitors-essential energy storage devices for modern electronics. This study focuses on enhancing specific capacitance and device-level energy storage by optimizing the interface between Ni(OH)₂-S and ZIF-67. In this work, we fabricate Ni(OH)₂-S/ZIF-67 composite, where Ni(OH)₂-S and ZIF-67 are bridged by sulfur (S). Electrochemical performance tests are carried out to evaluate the specific capacitance of obtained products, and asymmetric hybrid supercapacitors are also assembled using Ni(OH)₂-S/ZIF-67 as the positive electrode and carbon nanobowls (HCB-4h) as the negative electrode. At a current density of 1 A g⁻¹, Ni(OH)₂-S/ZIF-67 exhibits an excellent specific capacitance of 1020.6 F g⁻¹. This improvement is attributed to S-bridge, which induces the formation of Ni-S-Co bonds between Ni(OH)₂-S and ZIF-67, effectively promoting electron transfer. The assembled asymmetric device delivers an energy density of 22.79 Wh kg⁻¹ at a power density of 805 W kg⁻¹.