Impact of structural and chemical features on c,d) hydration and e–h) dopant solution energies. h) Reaction energy of host compound from the neighboring equilibrium phases (inverse distance to hull). Perovskites, reported proton-conducting non-perovskites, promising non-perovskites, and other non-perovskite compounds are indicated by yellow, green, blue, and grey circles, respectively. The promising non-perovskite compounds are the top eight unreported candidates, (Pb-doped) Bi12SiO20sillenite, (Ti-doped) Li3NbO4ordered rocksalt, (Sr-doped) Bi4Ge3O12eulytite, (Pb-doped) Cs3BiO3, (Pb-doped) Rb3BiO3, (Li-doped) K2Sn2O3, (Li-doped) K2Pb2O3, and (Mg-doped) ZnGa2O4spinel. The averaged hydration and dopant solution energies (Φ0) are −1.42 and 1.36 eV, respectively. Pyrochlores composed of trivalent and tetravalent cations are located at the top of (a), whereas those composed of divalent and pentavalent cations are located at the bottom.
