This book provides a description of material characterization and mechanisms of secondary batteries during discharge, cycle, and storage process. It also proposes a new intercalation/de-intercalation theory and presents the mechanism of ionic conduction. In addition, through the comparative study of variation laws of battery performance and of fine structure and microstructure parameters, the mechanism of cycle and storage processes and battery performance decay are investigated. Given its scope, the book appeals to a broad readership, particularly professionals at universities and scientific research institutes.