Determining the Gibbs Energy Contributions of Ion and Electron Transfer for Proton Insertion in ϵ-MnO₂

Electrochemically active ϵ-MnO₂ and ɣ-MnO₂ as tunnel-type host-guest structures have been extensively studied by crystallography and electrochemical techniques for application in battery cathode materials. However, the Gibbs energies of the underlying ion and electron transfer processes across the electrode interfaces have not yet been determined. Here we report for the first time these data for ϵ-MnO₂ . This was possible by measuring the mid-peak potentials in cyclic voltammetry and the open-circuit potentials under electrochemically reversible conditions.