A team led by an Indian-origin scientist has developed a flexible supercapacitor which can generate power from the Sun and store excess energy for later use. The technology developed by researchers from the University of Glasgow in the UK could pave the way for a new generation of flexible electronic devices, including solar-powered prosthetics for amputees.
The team led by Professor Ravinder Dahiya used layers of graphene and polyurethane to create the flexible supercapacitor, according to the study published in the journal Advanced Science. The researchers demonstrated the effectiveness of their new material by powering a series of devices, including a string of 84 light-emitting-diodes (LEDs) and a prosthetic hand, allowing it to grasp a series of object.
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The top touch sensitive layer is made from graphene, a highly flexible, transparent ‘super-material’ form of carbon layers just one atom thick, said Dahiya. Sunlight which passes through the top layer of graphene is used to generate power via a layer of flexible photovoltaic cells below.
Any surplus power is stored in a newly-developed supercapacitor, made from a graphite-polyurethane composite. The team worked to develop a ratio of graphite to polyurethane which provides a relatively large, electroactive surface area where power-generating chemical reactions can take place, creating an energy-dense flexible supercapacitor which can be charged and discharged very quickly.
Similar supercapacitors developed previously have delivered voltages of one volt or less, making single supercapacitors largely unsuited for powering many electronic devices. The team’s new supercapacitor can deliver 2.5 volts, making it more suited for many common applications, researchers said.
In laboratory tests, the supercapacitor has been powered, discharged and powered again 15,000 times with no significant loss in its ability to store the power it generates. “This is the latest development in a string of successes we have had in creating flexible, graphene based devices which are capable of powering themselves from sunlight,” said Dahiya, who led the research.
“Our new flexible supercapacitor, which is made from inexpensive materials, takes us some distance towards our ultimate goal of creating entirely self-sufficient flexible, solar-powered devices which can store the power they generate,” he said. “There is huge potential for devices such as prosthetics, wearable health monitors, and electric vehicles which incorporate this technology, and we are keen to continue refining and improving the breakthroughs we have made already in this field,” said Dahiya.