Cost of energy storage supercapacitors

Supercapacitors, bridging conventional capacitors and batteries, promise efficient energy storage. Yet, challenges hamper widespread adoption. This review assesses energy density limits, costs, materials, and scalability barriers.

High capital cost and low energy density of supercapacitors make the unit cost of energy stored (kWh) more expensive than alternatives such as batteries. Their attributes make them attractive for uses in which frequent small charges/discharges are required (e.g., ensuring power quality or providing frequency regulation).

Supercapacitors are developed within a small industry relative to other types of energy storage, such as batteries. Lithium-ion batteries have become the dominant storage technology for most grid applications through significant investment in innovation and scale-up of deployment, as well as the corresponding increased power densities at less cost.

As a result, commercially available supercapacitors typically exhibit energy densities ranging from 1 to 10 Wh/kg, significantly lower than lithium-ion batteries (100–265 Wh/kg), . The energy density (Wh/kg) and power density (kW/kg) of supercapacitors are compared with lithium-ion batteries and lead-acid batteries in Fig. 5.

One of the major drawbacks of supercapacitors is their relatively low energy density, which hinders their widespread adoption in applications requiring high energy storage capacities. Overcoming this limitation has been a significant challenge for researchers and engineers working on supercapacitor technology.

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.