There is a growing interest in developing thin film supercapacitors as power sources for the ever increasing micro and nano devices such as nano electromechanical systems, smart cards, micro sensors etc. To realize thin film supercapacitors for various applications, the development of high quality electrode is required. This book presents, Mn3O4 thin films are deposited on different substrates using E-beam evaporation technique. Further, the films are annealed at various temperatures and proved that the films grown on gold coated silicon substrates annealed at 300 °C exhibited superior electrochemical properties than as deposited films.