ABSTRACT
Electrochemical capacitor, also known as supercapacitor or ultracapacitor, is an energy storage device well known for its higher energy density compared to a conventional capacitor. Besides, it possesses higher power density than a normal battery which makes it eligible for applications that required fast charging discharging process such as regenerative braking and backup power supply. Electrochemical capacitor is a new generation of capacitor evolved after electrostatic capacitor, electrolytic capacitor, and double layer capacitor. Their primary principle is similar, that is, to store energy. Nowadays, an electrochemical capacitor has been integrated into various fields for example consumer electronics, telecommunication, optics, and transportation. Due to societal demand and environmental concern, a more efficient and sustainable energy storage device is needed. Since the benefits of nanomaterial are revealed, nanotechnology has invaded into manufacturing industry to produce lighter, smarter, and longer lasting products. It is predicted that, in future many products can be fabricated rapidly with a lower cost. Although it is difficult to estimate how soon this nanotechnology will be fully grown, the development is unavoidable and there is no doubt that the technology at the present time will be transformed. Therefore, the role of nanostructure materials inside energy storage device is paramount and intense study is still required in order to go beyond the state of art.
