Recently, all over the world is focusing to develop new electrolyte and electrode materials in order to meet the demand for power sources in modern electronic devices. The modified electrolyte, electrode materials and their functionality will be greatly enhancing the ionic device performance.The future energy devices and their technologies development depends on the electrolyte and electrode materials. Hence, the synthesis and characterization techniques related to polymer based composite electrolytes, nanostructured electrode materials are described. We hope this book will helpful for students, researchers, scientists and Professors for the development of new energy storage devices.