Low-temperature fuel cells: Outlook for application in energy storage systems and materials for their development

Low-temperature fuel cells (FCs) are perspective alternative energy sources. They cannot, however, be considered as a primary energy source, because no hydrogen in pure form, used in their operation, exists in nature. The development of devices to autonomously supply and store energy can be considered as one of the most promising applications of low-temperature FCs. In the latter case, the primary purpose is to compensate differences in peaks of producing and consuming energy both in the seasons and time of day. The first part of the review describes this problem. The second part involves analyzing nanomaterials used in FCs, so that hybrid membranes, including inorganic nanoparticles, are high priority in this regard. Their incorporation into the pores of the membranes leads to an improvement in transport properties in many cases, including an increase in ionic conductivity and selectivity of transport processes. These properties of the hybrid membranes are discussed by using a model of limited elasticity of walls of the pores. Catalysts, being platinum nano-size particles, play an important role in the FC. To reduce their costs and increase activity, some approaches, implying decrease in particle sizes or using two-component particles, for example, alloys and ‘core-shell’ particles, are used. In the latter case, platinum, localized on the surface, determines activity of the catalyst, whereas the second metal increases surface area and catalyst activity. The main reasons for changes in properties of the materials and effect of the catalyst support on electrochemical processes in FCs are also considered.