Developments in electrode design: Structure, decoration and applications of electrodes for electrochemical technology

The diversity of cell geometries and their use for electrochemical processing and energy conversion are concisely reviewed, updating earlier treatments, with an emphasis on an engineering approach to electrode design. Electrode size varies from several cm2 in the laboratory to a total of hundreds of m2 at industrial plant scale and currents can range from several nA at laboratory through many 100 kA in industry. Electrode materials include metals, conductive ceramics and polymers as well as polymer- metal or ceramic-metal composites. Area, electrocatalytic activity and functionality can be tailored by selecting an appropriate support structure-coating combination. The core structure of porous supports can be a foam, mesh or particulate bed while the surface can be enhanced by many techniques. Inspiration for electrode design can come from many sources, including biomimetics and technology transfer. Important aspects of electrodes include manufacture, electrochemical activity, active area, the possibilities of 3D and nanostructured surfaces, decoration and functionalisation, in addition to reasonable cost and adequate lifetime. The diversity of electrodes is illustrated by examples from the author’s laboratory in the fields of inorganic and organic synthesis, environmental remediation of wastewaters, surface finishing of materials and energy storage/conversion. A forward look is made to potential future developments in electrochemical technology