reprint, amsmath,amssymb, aps, ]revtex4-2 Breaking the Ionic-Conductivity Barrier in Amorphous Alumina: Copper Doping-Induced Electron-Ion Coupling for Next-Generation SOFC Electrolytes

reprint, amsmath,amssymb, aps, ]revtex4-2 The performance of solid oxide fuel cells (SOFCs) is critically influenced by the electrolyte’s ability to achieve high ionic conductivity while maintaining electronic insulation. Traditional materials, such as yttria-stabilized zirconia (YSZ), face a trade-off between these two properties. This study introduces copper-doped amorphous alumina as a novel strategy to enhance electron-ion (E-I) coupling, thereby boosting ionic conduction via localized charge transfer. By doping amorphous alumina with copper, we create additional electronic states that facilitate charge transfer, which in turn enhances ion mobility. Notably, increasing copper concentration results in a progressive enhancement of localized charge transfer, which maximizes ionic conduction. Through systematic doping at concentrations of 2.5%, 5%, 7.5%, and 10%, we identify 10% copper as the optimal composition for achieving superior conductivity and electrochemical performance. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) confirm the uniform incorporation of copper and the structural integrity of the doped material. The 10% Cu-doped alumina demonstrates an ionic conductivity of 0.16 S/cm and a peak power density of 770 mW/cm-2, significantly outperforming conventional SOFC electrolytes. This work underscores the potential of localized charge transfers in amorphous materials, positioning copper-doped alumina as a promising candidate for next-generation SOFCs. By enhancing ionic conduction through electron-ion coupling, this approach offers a pathway for the design of high-performance electrolytes with reduced activation energy and improved electrochemical stability.