Supplementary Dataset — α-MnO₂/Ni(OH)₂ Heterojunction Electrode Research

This supplementary dataset provides all raw experimental measurements and first-principles computational outputs underlying the manuscript. Data are organised into ten thematically distinct worksheets (S1–S10), spanning powder X-ray diffraction (XRD), density functional theory with Hubbard U correction (DFT+U), climbing-image nudged elastic band (CI-NEB) proton migration calculations, cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), electrochemical impedance spectroscopy (EIS), rate performance, long-term cycling stability, inductively coupled plasma optical emission spectrometry (ICP-OES), N₂ adsorption–desorption isotherms (BET/BJH), and a cross-validation table that quantitatively demonstrates agreement between computational predictions and experimental measurements. The dataset is designed to be fully self-contained: all values reported in the main text, figures, and tables can be directly traced to entries in this file.