The Indian Institute of Science (IISc) have developed an efficient supercapacitor printed onto a plastic sheet. The technology is lightweight, compact flexible.
Supercapacitors have the potential to one day replace batteries used in electric cars, cell phones or laptops, they charge very quickly, and work at almost 100 percent efficiency. However, they are generally bulky and can store only very limited amounts of energy at a time.
The challenge for researchers has been to reduce the size while increasing the power. Producing them using current techniques is also expensive and slow.
"We can actually print these supercapacitors anywhere, on any substrate; thus they can easily be mounted on any surface just like a simple spray on the walls."
The breakthrough by the Indian Institute of Science saw the researchers create their flexible supercapacitor by developing a spray coating technique of adding layers of hybrid nanocomposites onto a bendable plastic sheet. The alternating layer technique increases the surface area and the movement of the charges.
"We can actually print these supercapacitors anywhere, on any substrate; thus they can easily be mounted on any surface just like a simple spray on the walls," says senior author Abha Misra, associate professor at the Department of Instrumentation and Applied Physics, IISc.
Supercapacitors use static electricity to store charge instead of toxic chemicals like batteries.
Capacitors have broad range of application potential
Supercapacitors typically have two electrodes dipped in an electrolyte and separated by a thin insulator. When the electrodes are charged an electric field is created between them, which allows energy to be stored. A greater charge is generated when the electrodes have a larger surface area.
Supercapacitors work really well in instances when a quick burst of energy is needed such as turning on a flashlight, or as dynamic brakes in cars, trains, and elevators. Currently, supercapacitors cannot compete with batteries in most applications.
A supercapacitor would weigh 40 times as much as a regular battery with the same charge. The new technology developed by the Indian Institute of Science sprays thin alternating layers of MnO2-coated carbon nanotubes (CNTs) and reduced graphene oxide (rGO) stacked on top of a stainless steel mask adhered on a standard PET plastic sheet.
Breakthrough technique offers greater storage capacity than existing supercapacitors
This patterning increases the surface area and also positions the materials to allow for the charge to move efficiently. So far the results have proven to have greater storage capacity than existing supercapacitors.
Excitingly, bending the printed sheet did not affect its performance which means this type of supercapacitor building technique has potential in energy storage applications. Full details of the research can be found in the journal ACS Applied Materials and Interfaces.