Manipulating and Optimizing the Hierarchically Porous Electrode Structures for Rapid Mass Transport in Solid Oxide Cells

Abstract

Over the past decades, considerable efforts have been made to develop hierarchically porous electrodes for the high surface area, the fast velocity of fuels/products to/away from the reaction site, and the high loading of thermal-and/or electrochemical-catalysts. Manipulation of the hierarchical structure is one of the key steps for high performance in applications of efficient energy storage and conversion such as solid oxide cells. This review starts with a brief introduction to the basic concept of mass transport and how mass transport may affect performance. Then, the latest developments in enhancing the performance of cells through modification or optimization of the hierarchically porous electrode structures, including altering the geometry or morphology and increasing the triple-phase boundaries length of electrodes are summarized. Subsequently, the unique characteristics of microstructures that are critical to enhancing electrode performance and provide important insights into the mechanisms of performance (activity and durability) enhancement, aiming at achieving the rational design of better electrode architecture are highlighted. Finally, the remaining challenges for the knowledge-based design of highly efficient electrodes for electrochemical devices, together with possible directions and future perspectives for the development of highly efficient electrodes through optimization of microstructure are discussed.

A review of progress in proton ceramic electrochemical cells: material and structural design, coupled with value-added chemical production

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