Layered Oxygen-Deficient Double Perovskites as Promising Cathode Materials for Solid Oxide Fuel Cells.

Andrei I Klyndyuk,Dmitry A Medvedev,Dzmitry S Kharytonau,Ekaterina A Chizhova

doi:10.3390/ma15010141

Abstract

Development of new functional materials with improved characteristics for solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) is one of the most important tasks of modern materials science. High electrocatalytic activity in oxygen reduction reactions (ORR), chemical and thermomechanical compatibility with solid electrolytes, as well as stability at elevated temperatures are the most important requirements for cathode materials utilized in SOFCs. Layered oxygen-deficient double perovskites possess the complex of the above-mentioned properties, being one of the most promising cathode materials operating at intermediate temperatures. The present review summarizes the data available in the literature concerning crystal structure, thermal, electrotransport-related, and other functional properties (including electrochemical performance in ORR) of these materials. The main emphasis is placed on the state-of-art approaches to improving the functional characteristics of these complex oxides.

Highlights

Fuel cells (FCs) are electrochemical devices in which the chemical energies of different fuels can be directly and effectively converted into electrical energy in one stage [1,2]
Taking into account peculiarities of the SOFC’s design, they can be divided into typical asymmetrical (A–SOFCs, in which the cathode and the anode are made of different materials) and symmetrical (S–SOFCs, in which the cathode and the anode materials are the same) derivatives [4]
SOFCs are divided into three groups according to their operation temperatures: high-temperature SOFCs (HT–SOFCs, 1073–1273 K, and ZrO2- or CeO2-based solid electrolytes), intermediate–temperature SOFCs (IT–SOFCs, 873–1073 K, and LaGaO3-based solid electrolytes), and low–temperature SOFCs (LT–SOFCs, < 873 K, and δ-Bi2O3 or Bi4V2O11-based solid electrolytes) [5,6,7,8,9,10]

Summary

Introduction

Fuel cells (FCs) are electrochemical devices in which the chemical energies of different fuels (including fossil fuels) can be directly and effectively converted into electrical energy in one stage [1,2]. In FCs the restrictions of the Carnot cycle are absent; the thermodynamic efficiency of these devices may reach 90% and higher [3] depending on their composition, interval of working temperatures, etc These devices are categorized into different groups which consider geometrical design [1], fuel (hydrogen, biomass, hydrocarbons, alcohols, etc.) [2], used electrolyte (proton-conducting membranes, oxygenand proton-conducting solid oxide fuel cells (SOFCs), etc.) [3], and operating temperature range (low-temperature, intermediate-temperature, and high-temperature FCs), etc. Due to the high tolerance of perovskite structure, these complex oxides can be formed at different combinations of their constituents, demonstrating outstanding thermal, electrotransport-related, magnetic, electrochemical, and other properties As a result, these double perovskites can be used as working elements of chemical gas sensors, high-temperature thermoelectrics, cathode materials of IT–SOFCs, etc. The present article provides an overview of peculiarities of the crystal structure, physicochemical properties, and electrochemical performance of layered oxygen-deficient perovskites as cathode materials of SOFCs, as well as ways and methods of improving the functional characteristics of these materials

Cathode Materials for IT–SOFCs

The Other Layered Oxygen-Deficient Double Perovskites

Findings

Short Resume