CuBr by impedance spectroscopy

Abstract The electrical properties of polycrystalline copper(I) bromide were investigated between 20 and 430 °C by impedance spectroscopy with copper electrodes. Extrinsic and intrinsic regions in γ-CuBr and a domain of fast ionic conduction in β-CuBr are separated. Enthalpies of migration of copper interstitials (25 kJ/mol) and copper vacancies (50 kJ/mol) and the enthalpy of formation of Frenkel defects (160 kJ/mol) are deduced. The phase boundary copper/copper(I) bromide can be represented by a parallel circuit of an interfacial resistance and a constant phase-angle (CPA) element. The interfacial resistance depends exponentially on temperature and is practically negligible above 350 °C. Contributions of charge transfer resistance and space charge resistance are discussed. Prefactors of CPA elements depend also exponentially on temperature; they are compared with interfacial capacitances.