The demand for rooftop solar paired with energy storage systems is expected to reach $1bn in the US within four years, according to the Solar Energy Industries Association.

The pairing of solar panels and batteries will enable users to store energy during the day and use it at night.

Solar energy storage systems therefore require battery banks with high specific energy to store maximum electricity without increased size.

The system should have the ability to handle large number of charge-discharge cycles prior to battery replacement.

BioSolar’s BioSuperCap energy storage supercapacitor demonstrated stability for 50,000 charge-discharge cycles.

BioSolar CEO David Lee said: "Existing battery technologies, such as lithium-ion batteries, are good for longer-term energy storage, but cannot be charged or discharged rapidly. Furthermore, batteries have limited charge-discharge life cycles resulting in premature capacity degradation over relatively short time span.

"By integrating our BioSuperCap, a low cost polymer-based supercapacitor, as the front-end to battery banks, fewer batteries can be used, and daytime solar energy can be quickly and cost-effectively stored for nighttime use at a substantially lower cost.

"The combined system also will be able to handle much larger number of charge-discharge cycles resulting in substantially longer battery life."