Abstract:

Hybrid energy storage devices (HESDs) are a new type of energy storage devices which combine the energy storage mechanism of double layer capacitance and pseudocapacitance, or supercapacitors and secondary batteries together in one system. HESDs can be classified as asymmetric supercapacitors (ASCs) and battery-supercapacitors (BSCs). HESDs have electrochemical performance such as high rate density, long cycle stability and safety like traditional supercapacitors and also possess high energy density equivalent to secondary rechargeable batteries. HESDs can be used as power sources for multi-function electronic equipments and electric/hybrid vehicles in the future. In this paper, energy storage mechanism, the development of the electrolytes, electrode materials and the full cell fabrication and performance are reviewed in detail. Finally, an outlook about the development perspectives, trends and the challenges for HESDs is presented.

Key words:  hybrid energy storage device, asymmetric supercapacitor, battery-supercapacitor