In Situ Grown Oxygen-Vacancy Rich NiCo-LDHs for High-Performance Supercapacitors

Abstract

Layered double hydroxides (LDHs) are increasingly recognized as highly promising electrode materials for supercapacitors, owing to their exceptional specific capacitance, notable redox activity, and superior anion exchange capability. However, several challenges still need to be addressed to achieve the theoretical specific capacitance and excellent rate capacity, including poor electronic and ionic conductivity. In this study, a two-step method was employed to prepare high electronic and ionic conducting NiCo-LDH-V_o materials, demonstrating enhanced electrochemical performance as supercapacitor electrodes. First, NiCo-LDH was directly electrodeposited onto high-conductivity nickel foam, which enhanced the electronic conductivity and avoided the effects of adhesives. Second, soak NiCo-LDH in H₂O₂ solution to introduce more oxygen vacancies. The resulting NiCo-LDH-V_o exhibited higher electron conductivity and ion diffusion ability, leading to increased specific capacity and long-term stability (771.8 C g⁻¹ at 1 A g⁻¹ with an excellent capacity retention rate of 92%).