The Encyclopedia of Electrochemical Power Sources, Second Edition, is a comprehensive seven-volume set that serves as a vital interdisciplinary reference for those working with batteries, fuel cells, electrolyzers, supercapacitors, and photo-electrochemical cells. With an increased focus on the environmental and economic impacts of electrochemical power sources, this work not only consolidates extensive coverage of the field but also serves as a gateway to the latest literature for professionals and students alike. The field of electrochemical power sources has experienced significant growth and development since the first edition was published in 2009. This is reflected in the exponential growth of the battery market, the improvement of many conventional systems, and the introduction of new systems and technologies. This completely revised second edition captures these advancements, providing updates on all scientific, technical, and economic developments over the past decade. Thematically arranged, this edition delves into crucial areas such as batteries, fuel cells, electrolyzers, supercapacitors, and photo-electrochemical cells. It explores challenges and advancements in electrode and electrolyte materials, structural design, optimization, application of novel materials, and performance analysis. This comprehensive resource, with its focus on the future of electrochemical power sources, is an essential tool for navigating this rapidly evolving field.