Ba(Ce,Zr)O₃-based electrodes for protonic ceramic electrochemical cells: towards highly compatible functionality and triple-conducting behaviour

Abstract

Protonic ceramic fuel cells and electrolysis cells represent low- and intermediate-temperature electrochemical devices, which allow chemical-to-electrical energy conversion with very high efficiency and low environmental impact. In order to ensure the long-term operability of these devices, as well as to provide for their up-scaling, a number of existing challenges associated with chemical and thermal incompatibilities pertaining to the functional materials remain to be overcome. This work presents a comprehensive overview of new electrode materials based on barium cerate/zirconate. The structural fragments of these materials are similar to those of the proton-conducting Ba(Ce,Zr)O3 electrolytes, which causes superior chemical compatibility between different functional materials. The primary emphasis of the research is on the functional properties of these materials such as chemical stability, thermal expansion behaviour and transport features. This in turn determines the electrochemical performance of the designed electrodes. In addition, the possibility of obtaining triple-conducting materials is discussed as means of designing electrodes with a high electrochemical active surface area required for the design of high-performance protonic ceramic fuel and electrolysis cells. The bibliography includes 208 references.

Chemical lattice strain in nonstoichiometric oxides: an overview

“…6 For the typical proton-conducting oxide hydration process, expressed asif Shannon radii 81 are used and hypothesized, direct application of eqn (32) yields negative chemical expansion, contradicting the experimental data. 6,65,67–69,150–161 Instead of making within the model smaller than , the authors 6 adopted another approach – it was assumed that the formation of oxygen vacancy decreases the coordination numbers of neighboring cations. Basically, taking and assuming the CN of cations to be nonstoichiometry-dependent are two somewhat equivalent 72 ways of describing the same phenomenon – the crystal lattice relaxation around the oxygen vacancy.…”

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

“…Recently, it has been shown that effective cathodes for proton-conducting SOFCs operating at low and intermediate temperatures are Ba(Ce,Zr)O 3 -based solid solutions doped with transition elements in high concentration. These phases demonstrate excellent chemical compatibility with typical proton-conducting solid electrolytes due to the similarity of their compositions [ 43 , 44 ]. These compounds belong to the triple-conducting oxides (TCOs) [ 45 , 46 , 47 ], in which transport species are simultaneously protons, oxygen ions, and electrons (holes).…”

Methods Used for the Compaction and Molding of Ceramic Matrix Composites Reinforced with Carbon Nanotubes

“…The methods described above are powerful for molding ceramics from prospective inorganic materials that would come in broad use in the near future [213][214][215][216][217][218]. An innovative composite material has been reported very recently, which demonstrated an extremely high resistance against abrasive wear under the action of cutting tools and water jets [219].…”