High-Entropy Perovskite Oxide: A New Opportunity for Developing Highly Active and Durable Air Electrode for Reversible Protonic Ceramic Electrochemical Cells

Abstract

Reversible proton ceramic electrochemical cell (R-PCEC) is regarded as the most promising energy conversion device, which can realize efficient mutual conversion of electrical and chemical energy and to solve the problem of large-scale energy storage. However, the development of robust electrodes with high catalytic activity is the main bottleneck for the commercialization of R-PCECs. Here, a novel type of high-entropy perovskite oxide consisting of six equimolar metals in the A-site, Pr1/6La1/6Nd1/6Ba1/6Sr1/6Ca1/6CoO3−δ (PLNBSCC), is reported as a high-performance bifunctional air electrode for R-PCEC. By harnessing the unique functionalities of multiple elements, high-entropy perovskite oxide can be anticipated to accelerate reaction rates in both fuel cell and electrolysis modes. Especially, an R-PCEC utilizing the PLNBSCC air electrode achieves exceptional electrochemical performances, demonstrating a peak power density of 1.21 W cm−2 for the fuel cell, while simultaneously obtaining an astonishing current density of − 1.95 A cm−2 at an electrolysis voltage of 1.3 V and a temperature of 600 °C. The significantly enhanced electrochemical performance and durability of the PLNBSCC air electrode is attributed mainly to the high electrons/ions conductivity, fast hydration reactivity and high configurational entropy. This research explores to a new avenue to develop optimally active and stable air electrodes for R-PCECs.

Electrochemical Properties of La0.6A0.4Co0.2Fe0.8O3 (A = Sr, Ca, Ba) as a Bifunctional Electrode for Reversible Solid Oxide Cells

“…With the temperature decreasing, the R p value gradually increases, but at any temperature, LBCF shows the maximum R p value, while LCCF shows the minimum R p value. Relevant literature shows that the higher the catalytic activity of the electrode material, the smaller the R p value of the symmetrical cell composed of it. , Therefore, LCCF exhibits the best catalytic activity toward the HOR. Moreover, k q values could reflect the magnitude of the electrochemical surface exchange reaction, and the corresponding values are shown in Figure e.…”

A synergistic dual-phase air electrode enables ultrahigh and durable performance of reversible proton ceramic electrochemical cells

“…Half-cells and electrolyte sheets were prepared by spin-coating and die-casting methods, respectively, and then calcined at 1450°C and 1400°C for 5 hours, respectively 11 . 1g of electrode powder was ball-milled with 10ml of isopropyl alcohol, 2ml of ethylene glycol and 1ml of glycerol at 400rpm for 30 minutes to make a well-mixed air electrode slurry.…”

“…Although favorable progress in a relatively short period of time for the R-PCECs [9][10][11][12][13] , their commercialization is still limited, mainly due to the insu cient electrochemical performance at the medium temperature range, as caused by the scarcity of high-e ciency air electrode with high activity in both FC and EC modes. Designing alternative air electrodes with high oxygen activation and hydration capabilities is an attractive approach to improve the kinetic rate of oxygen reduction and oxygen evolution reactions (ORR and OER) in R-PCFCs 14,15 .…”

Large Energy Capacitive High-Entropy Lead-Free Ferroelectrics

“…(Bi 0.5 Na 0.5 )(Ti 1-2x Fe x Nb x )O 3 (abbreviated as BNTFN-x, x = 0, 0.1, 0.2, 0.3, 1/3) ceramics were fabricated by a conventional solid-state reaction method with the ΔS config of 0.69R, 1.33R, 1.64R, 1.78R, and 1.79R, respectively, which can be calculated using the following formula in perovskite [23,24]: where x a , x b, and x c are the mole fraction of the ions present in the A-site, B-site, and O-site, respectively. When ΔS config < 0.69R, it is a low-entropy material.…”