The structure and electrical properties of novel BaSn0.15Ce0.35Hf0.25Y0.1Yb0.1Ho0.05O3-δ high-entropy proton-conducting electrolyte

In this article, the structure and electrical properties of BaSn _0.15Ce _0.35Hf _0.25Y _0.1Yb _0.1Ho _0.05O _3-δ (referred as BSCHYYbHo in forthcoming discuss) high-entropy ceramic have been investigated. The BCHYYb (short for BaCe _0.5Hf _0.3Y _0.1Yb _0.1O _3-δ ) and BSCHYYbHo pellets were synthesized successfully by the solid-state reaction method. The XRD detection results indicate that there is no secondary phase appeared in BSCHYYbHo and the lattice constant decrease compared to BCHYYb. The surface SEM and EDS images illustrates that BSCHYYbHo is denser than BCHYYb and the elements distribution is more uniform. The DFT calculation proves that BSCHYYbHo has a tend to maintain single phase structure. The electrical properties of BSCHYYbHo is obtained by the DRT analysis and equivalent circuit method based on defect equilibria model. The total conductivity of BSCHYYbHo is about 2.02 × 10 ^-4 ∼1.01 × 10 ^-2 S·cm ^-1 and standard molar hydration enthalpy of BSCHYYbHo is recorded as − 81.8 kJ/mol. Further, the proton, oxygen vacancies and electron holes conductivity activation energies in BSCHYYbHo is estimated to be 0.45 eV, 1.41 eV and 1.60 eV, respectively. Compared to BCHYYb, BSCHYYbHo electrolyte has higher proton concentration and proton transference number. Overall, BSCHYYbHo ceramic with dense structure and high proton transference number is a potential material for application.