Although lithium-ion batteries (LIBs) are the dominant technology used in portable electronics, electric vehicles, and stationary power stations, there is concern about the long-term availability and sustainability of lithium to meet demand. Sodium batteries (SBs) are seen a viable alternative, as sodium is abundant, and because the battery components and electrical chemistry of SBs and LIBs are similar, SBs are poised to take advantage of the existing infrastructure and mature manufacturing technologies of LIBs and can serve as a drop-in technology. This book provides an in-depth overview of fundamentals, advanced materials, characterization, functional mechanisms, technologies, and applications of SBs. It introduces a wide range of SBs and discusses how to improve their performance and extend their lifecycle for commercial use. • Examines material design, selection, synthesis, structural and property characterization, and related issues. • Details advanced characterization technologies including artificial intelligence and theoretical calculations applied in these batteries. • Analyzes advances in the electrochemical energy storage and conversion of various SBs to keep up with rapidly changing commercial requirements. • Discusses safety of use in grid energy storage and conversion and electric vehicles. • Provides strategies for increasing performance, assembling, and fabrication toward commercialization. • Summarizes achievements, challenges, and future research directions. Aimed at chemical, materials, and energy engineers, researchers, and advanced students, this book serves as a valuable resource to assist in the development and commercial application of sodium batteries.