A composite material panel that functions as a solar cell to generate as well as store electricity as a structural supercapacitor has been engineered by researchers from University Malaysia and Yangon Technological University (Myanmar). The panels can be used as a structural component in electric vehicles (EVs) and form a hybrid energy storage system together with rechargeable batteries.

Prototypes of the solar supercapacitor-based composite panels were prepared by sandwiching thin paper film between layers of zinc oxide-filler epoxy resin (ER) and copper oxide-ER. The paper film was soaked in sodium sulfate electrolytes which serve as a dielectric medium between carbon fiber electrodes. Two electrodes composed of zinc oxide-carbon fiber and copper oxide-carbon fiber form the electrical double layer supercapacitor.

The presence of copper oxide increases electron transfer along the surfaces of zinc oxide nanostructures and leads to a faster charging time. The conductivity of solar supercapacitor samples improved with an increase in zinc oxide/copper oxide content, and samples with 20 gm2 paper soaked in the electrolyte show higher capacitance than samples with plain dielectric paper.

An energy conversion efficiency of 17.78%, an open-circuit voltage of 0.79 mV, a current density of 222.22 A/m2, a capacitance of 11.17 μF/cm2, an energy density of 120 Wh/kg and a power density of 29 kW/kg were documented for an optimized sample. A fully charged solar supercapacitor under solar irradiance of 1,000 W/m2 provides an additional 4.56% power generation and range per hour for conventional EVs. The SSC detailed in Materials Research Express has the potential to reduce EV battery size by 10% and weight by 7.5% for the same power output.

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