Modern approaches to increasing the efficiency of solid-oxide fuel cells (SOFCs) based on electrolytic membranes with mixed conductivity are considered. These approaches are based on material-science concepts (expansion of the electrolytic domain boundary due to the doping of basic oxides and development of various composite materials) and various technological solutions (application of electron-blocking layers on the anode and cathode sides, rational selection of the electrolyte thickness, and optimization of the electrolyte and electrode structures by synthesizing heterostructures). The methods of mathematical modelling of devices with an electrolytic membrane having mixed conductivity are analyzed in order to determine the most efficient design and optimal operation conditions for SOFCs. The application of nanocomposite electrolytes with a core – shell structure and salt composites is considered. Data on new design solutions — single-layer and single-chamber SOFCs — are presented. The prospects of the proposed approaches are evaluated. The bibliography includes 384 references.

The key features and challenges of the use of electrophoretic deposition for the formation of functional layers of solid oxide fuel cells are considered. Theoretical models and experimental results of the studies of electrophoretic deposition are presented. The analysis covers the physicochemical deposition mechanisms, methods for preparing suspensions and conditions necessary for obtaining thin-film electrode and protective single- and multi-layers with both dense and porous structure for solid oxide fuel cells. The prospects of theoretical simulations of the method and its potential practical applications are evaluated. The bibliography includes 282 references.

Thin film technologies have attracted ever-growing interest in different industrial areas. Concerning solid oxide fuel cells (SOFCs), especially devices operating in the intermediate temperature range, such technologies are applied particularly for the deposition of dense, gas-tight electrolyte films with a thickness of several µm to decrease ohmic resistance and enhance the cell performance. The main requirements for the technology selected are its low cost, simplicity of the equipment used, short deposition time and flexibility regarding the cell shape. First, we overview thin-film technologies adapted to the deposition of SOFC functional layers, discussing their strengths and weaknesses, with special attention given to electrophoretic deposition (EPD) as being the most simple and cost-effective colloidal method to fabricate different electrolyte films. Then we present the contribution of our scientific group in the development of the EPD method. The preparation of stable suspensions for the EDP is one of the key requirements for its successful implementation and reproducibility; this was considered in detail and the effect of self-stabilization in suspensions based on nanopowders (7-15 nm), obtained by the method of laser evaporation with consequent condensation, was discussed. Such suspensions, exhibiting high positive ζ-potential values (30-50 mV), were shown to be suitable for EPD without the addition of dispersants or iodine. The requirements for the electrode substrates were formulated and a model of particle aggregation near the porous substrate surface was proposed. Deposition parameters were established for different electrolyte films -commonly used yttria-stabilized zirconia, single and multiply doped CeO 2 and proton-conducting doped BaCeO 3 electrolytes. As was shown, the deposition on the highly conducting cathode substrates is simpler to implement than the EPD on non-conducting anode substrates and, in addition, it produces high quality films which render high OCV values and superior SOFC performance.

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