The electrochemical mechanism and transport phenomenon of liquid fuel cells

Recently, increased demand for renewable energy use has led to increased interest in energy conversion and storage systems. Among the various energy conversion systems, fuel cells have been studied extensively due to the high energy conversion efficiency and high energy density of the fuels used. Although fuel cells are considered as a key element in the transition to the so-called hydrogen economy, its use is restricted due to problems related to the production, storage, and transportation of gaseous hydrogen. Compared to gaseous hydrogen, alcohols in liquid form have attracted more attention as an alternative energy source for fuel cells thanks to their advantages, such as high volumetric energy density, easy availability, and storage and transportation possibilities. In this chapter, the working principles of direct liquid/alcohol fuel cells in which alcohols such as methanol, ethanol, and ethylene glycol are used as energy sources, as well as the electrochemical reactions that take place in acidic and alkaline environments, are examined in detail. © 2021 Elsevier Inc. All rights reserved.