Chapter 10:Membranes for Solar Fuels Devices

Membranes are employed in photoelectrochemical solar fuels devices to permit the transport of electrolyte ions while minimizing the transport of oxidation and reduction products between electrodes, thereby contributing to improved product purity and overall device efficiency. This chapter outlines the principal challenges and design criteria for these essential device components. Fundamentals of polymer chemistry, membrane structure, and small molecule and ion transport in polymeric membrane films are presented, and phenomena that induce changes in membrane transport properties are described. The use of several common commercial polyelectrolyte membranes is discussed. Membrane research within JCAP is summarized, including the development of new polymer chemistries, device architectures that integrate a membrane with catalyst materials, and development of measurement techniques useful for characterizing membrane transport of gases, ions, and neutral molecules in aqueous solutions. An outlook on the use of membranes in CO2 reduction devices provides perspective on additional requirements for photoelectrochemistry applications.