Electrochemical capacitors (also called supercapacitors) are characteristic of high power density, long lifecycle, and bridging function for the power/energy gap between traditional dielectric capacitors (which have high power output) and batteries/fuel cells (which have high energy storage). The objective of this book is to give overall ideas related to supercapacitor, how to synthesis electrode materials like activated carbon, graphene, conducting polymer, how to characterize these materials, how to fabricate the supercapacitor and finally, we had given all the calculation to determine the property of supercapacitor. So, this book definitely will give overall representation about supercapacitor for those who are in earlier carrier in the study of electrochemical power sources.