This book covers the latest research on applications of nanomaterials in the field of energy systems and devices. It provides an overview of the state-of-art research in this rapidly developing field. It discusses the design and fabrication of nanostructured materials and their energy applications. Various topics covered include nanomaterials for perovskite solar cells, transition metal dichalcogenides (TMDs) nanocomposites based supercapacitors, battery materials and technologies, major challenges toward development of efficient thermoelectric materials for energy efficient devices, extraction and experimentation of biodiesel produced from leachate oils of landfills coupled with nano-additives aluminium oxide and copper oxide on diesel engine and many more. It has contributions from world-renowned specialists in the fields of nanomaterials and energy devices. The book will be useful for students, researchers and professionals working in the area of nanomaterials and energy systems & devices.