Current developments in reversible solid oxide fuel cells

Solid Oxide Fuel Cells (SOFC) and Solid Oxide Electrolyte Cells (SOEC) are often considered precluded mainly by their high cost, even when several technical issues have been continuously tackled over the past decades. Our energetic matrix is essentially based on finite fuel sources, which involve the emission of environmentally hazardous pollutants. Nevertheless, now there are several feasible and profitable benign routes for energy generation through solid oxide cells development, mainly for cells capable to produce energy and store it employing hydrogen as energy carrier. Those cells act reversibly as fuel or electrolyzer systems, which may be integrated in hybrid renewable energy plants and may be referred to as Reversible Solid Oxide Fuel Cells (RSOFC). In this article, the operation principles of SOEC and SOFC and the current state of the electrolyte, fuel and oxygen electrodes has been reviewed and discussed in detail. Each major section is divided into materials families, including manufacturing issues. Novel materials and processing techniques are currently in development and are summarized here. Moreover, key-points are suggested to overcome the known drawbacks and to improve the performance and economic feasibility in order to enhance the commercialization of RSOFC technology.