Like batteries, supercapacitors store and release electricity. But unlike batteries, supercapacitors don’t need a chemical reaction to store energy. Instead, electric charge is stored electrostatically, which allows supercapacitor to be rapidly charged and discharged. Scientists from Clemson University and the Indian Institute of Science have developed a metal oxide-based optically responsive symmetrical supercapacitor using a novel stacked vanadium pentoxide/zinc oxide semiconducting heterostructure on fluorine-doped tin oxide glass.
Chauhan et al. designed a smart supercapacitor using a novel stack of metal oxides that can efficiently harvest energy from sunlight and simultaneously store it. Image credit: Chauhan et al., doi: 10.1039/D2TA06790K.
Although solar energy is renewable, one challenge is that it is harvested during the day when the Sun is out and must be stored for future use.
That traditionally required two separate devices — one to harvest the light into electricity and another to store it. Having both makes the overall system bulky.
Indian Institute of Science’s Professor Abha Misra and colleagues developed a smart device that converts light to electrical energy and stores it, reducing bulkiness.
Zinc oxide has been widely used in light-dependent charge transfer applications, such as photovoltaics and photocatalysis, because of its low cost, high carrier mobility, long carrier diffusion, ease of synthesis on substrates and non-toxicity.
It has electron transporting and hole-blocking characteristics and readily generates photo-excited electrons on light irradiation.
However, its wide band gap restricts its utility to a narrow light spectrum, requiring a novel strategy to improve its performance.
The researchers stacked vanadium pentoxide and zinc oxide to create a unique heterostructure, one which improved on past materials’ ability to convert light to electrical energy
In a test to measure its ability to store harvested light, the new device bested the previous record by a factor of four.
“We’ve come up with a two-in-one device that not only harvests light more efficiently but also stores it as electrical energy, unlike the other systems that exist right now,” said Dr. Mihir Parekh, a researcher in the Clemson Nanomaterials Institute at Clemson University.
“The materials we chose allowed us to engineer the band gap so that the light-to-electricity conversion was very efficient.”
the scientists found that the device showed excellent electrochemical performance and stability for over 5,000 cycles.
“What we are essentially doing here is trying to harvest every ounce of energy around us in nature,” said Clemson Nanomaterials Institute’s Professor Apparao Rao.
“We have much sunlight. The driving force behind the research is to open doors to another technology besides solar cells, which has already become a mature field, to capture the energy that is all around us.”
The team’s work was published in the Journal of Materials Chemistry A.
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Pankaj Singh Chauhan et al. 2023. Stacked vanadium pentoxide-zinc oxide interface for optically-chargeable supercapacitors. J. Mater. Chem. A 1: 95-107; doi: 10.1039/D2TA06790K
Source : Breaking Science News