High-Entropy Perovskite Electrolyte for Protonic Ceramic Fuel Cells Operating below 600 °C

Abstract

High-entropy materials are attracting ever-increasing concern for their unique structural features and unprecedented potential applications. In this study, we design and successfully prepared single-phase high-entropy perovskite oxide (HEPO) BaSn0.16Zr0.24Ce0.35Y0.1Yb0.1Dy0.05O3−δ (BSZCYYbD) to use as a new class of proton conductor, which is first applied to protonic ceramic fuel cells (PCFCs) below 600 °C. The BSZCYYbD exhibits excellent chemical and structural stability, high densification, and mechanical properties. The protonic conduction in BSZCYYbD is proved by the proton-conductor isotope effect and hydration effect. The protonic conductivity of BSZCYYbD is the highest ever reached in the high-entropy proton conductors, which is 8.3 mS cm–1 in humidified air (3% H2O) at 600 °C. An anode-based PCFC with BSZCYYbD electrolyte (∼45 μm) demonstrates a favorable output of 318 mW cm–2 at 600 °C. Our study offers a strategy for the design of superior proton-conducting electrolytes based on HEPOs, which hold promise for diverse electrochemical applications.

High‐Entropy Perovskites for Energy Conversion and Storage: Design, Synthesis, and Potential Applications

“…[ 36 ] Chen et al [ 37 ] synthesized (La 1/5 Pr 1/5 Dy 1/5 Ho 1/5 Tm 1/5 )Ta 3 O 9 and tested its Vickers hardness, finding it to be significantly higher (10.2–11.4 GPa) than that of the low‐entropy perovskites DyTa 3 O 9 (8.8 GPa), ErTa 3 O 9 (9.1 GPa), and GdTa 3 O 9 (9.3 GPa). [ 37 ] Similarly, the HEP proton conductor BaSn 0.16 Zr 0.24 Ce 0.35 Y 0.1 Yb 0.1 Dy 0.05 O 3− δ developed by Guo et al [ 38 ] exhibited a high hardness of 5.9 GPa, exceeding that of conventional BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (≈4 GPa). [ 39 ] The coefficient of thermal expansion is strongly related to the material's composition.…”

Functional two-dimensional high-entropy materials

“…There has been a growing research focus using the concept of high entropy in all components of an energy storage device, the electrodes (anode and cathode) 46,58 , as well as solid- 59,60 , and liquidstate electrolytes 61 (Fig. 3a, b).…”

On the Effect of Standard Deviation of Cationic Radii on the Transition Temperature in Fluorite-Structured Entropy-Stabilized Oxides (F-ESO)

“…Several aspects of these new materials were thoroughly investigated during these last few years. First, ESOs and HEOs owning other crystal structures than rock-salt were discovered and synthesized, such as fluorite [ 3 , 4 ], perovskite [ 5 , 6 ], pyrochlore [ 7 ], magnetoplumbite [ 8 ], garnet [ 9 ], and spinel [ 10 ]; a detailed review about the compositions for different families of HEOs was authored by Akrami et al [ 11 ]. Then, several papers reported very promising, and often unexpected, technological properties for both ESOs and HEOs, especially in the field of energy storage systems [ 12 , 13 , 14 ], thermal barrier coatings [ 15 , 16 ], multipurpose catalysts [ 17 , 18 , 19 ], and magnetic systems [ 20 ].…”