Gamma-irradiation assisted synthesis of nickel-cobalt oxide composites: Crystal structure dependency for supercapacitor efficiency

Abstract

This study explored an innovative gamma-irradiation approach for the synthesis of nickel-cobalt oxide (NCO) composites for advanced supercapacitors. Varying irradiation doses facilitated the formation of mixed-phase structures, where XRD analysis revealed a dose-dependent relationship between rock-salt (NiO or NiCoO₂) and spinel (Co₃O₄ or NiCo₂O₄) phases. The composite synthesized at 300 kGy (300NCO) achieved a specific capacitance of 73 F.g−1. Furthermore, the diluted-precursor method for preparation NCO at 300 kGy (300NCO_D) demonstrated a better electrochemical performance than 300NCO, achieving a specific capacitance of 103.5 F.g−1. Additionally, gamma-irradiation treatment at 5 kGy applied to the 300NCO_D electrode in a Swagelok cell improved long-term stability, retaining 92 % capacitance over 10,000 cycles. This study highlights gamma irradiation as a clean and scalable method to significantly tune phase formation in bimetallic oxides, advancing energy storage technology by enhancing electrode uniformity and stability.