Trakulmututa J.Weerasuk B.Sataman P.Chutimasakul T.Kamonsuangkasem K.Smith S.M.Sirisit N.Sangtawesin T.Mahidol University2025-02-012025-02-012025-02-05Journal of Alloys and Compounds Vol.1014 (2025)09258388https://repository.li.mahidol.ac.th/handle/123456789/103147This 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.Materials ScienceEngineeringArticleSCOPUS10.1016/j.jallcom.2025.1787362-s2.0-85216112220