Electrochemical capacitors (i.e., supercapacitors) as energy storage technologies have attracted a lot of attention because of the increasing demand for efficient high-power delivery. Over the past decades, various advanced electrode materials and cell design have been developed to improve the performance of electrochemical capacitors.
The review covers supercapacitor material, fabrication, and performance limits. It reviews cycle life, and cost to offer an overview of supercapacitor improvement. It highlights novel supercapacitor materials and designs in future. Supercapacitors, bridging conventional capacitors and batteries, promise efficient energy storage.
The development of electrochemical capacitors (i.e. supercapacitors) have attracted a lot of attention in recent years because of the increasing demand for efficient, high-power energy storage.
Although supercapacitors have improved, newer high-power batteries, such as thin-film lead acid and lithium-ion are offering power densities previously only achieved in electrochemical capacitors. Coupled with their greater capacity and energy, these cells are offering a significant challenge to developers of electrochemical capacitors.
Electrochemical capacitors (ECs) often describe electrical double-layer capacitors (EDLCs), supercapacitors, ultracapacitors, pseudo capacitances, gold capacitors, power capacitors or power caches [ 1 ]. In terms of power and energy densities, ECs lie in-between batteries and conventional dielectric capacitors.
High power standard capacitors are capable of fast discharge, but they lack the energy density of SCs. SCs are eco-friendly, lead (Pb)-free, Restriction of Hazardous Substances (RoHS)-compliant, and have no disposal issues at end of their lifecycle.