Carbon nanotubes have been used in everything from energy-free lights to oil spill clean-up technology, and now a team from Rice University has used them to develop a paint that transforms any surface into a lithium-ion battery! This transformative paint holds the potential to create a functional, rechargeable solar battery on just about any surface.
The Rice University team’s rechargeable battery consists of spray-painted layers, each representing the components in a traditional battery. “This [design] means that traditional packaging for batteries has given way to a much more flexible approach that allows all kinds of new design and integration possibilities for storage devices,” said Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science and of chemistry. “There has been lot of interest in recent times in creating power sources with an improved form factor, and this is a big step forward in that direction.”
The team showcased the first test device for their paintable batteries on an array of standard ceramic tiles that was combined with a solar cell and an array of LEDs. The LEDS were arranged to form ‘RICE’ and were lit up by the 2.4 v emitting batteries for over six hours.
The battery’s development has been a long process with the team spending hours formulating, mixing and testing paints for each of the five layered components. The paint was then airbrushed onto a variety of surfaces, including ceramic bathroom tiles, flexible polymers, glass, stainless steel and even a beer stein to see how well they would bond with each substrate.
The battery’s multiple layer design is described in Nature’s online, open-access journal Scientific Report. “The first layer, the positive current collector, is a mixture of purified single-wall carbon nanotubes with carbon black particles dispersed in N-methylpyrrolidone. The second is the cathode, which contains lithium cobalt oxide, carbon and ultrafine graphite (UFG) powder in a binder solution. The third is the polymer separator paint of Kynar Flex resin, PMMA and silicon dioxide dispersed in a solvent mixture. The fourth, the anode, is a mixture of lithium titanium oxide and UFG in a binder, and the final layer is the negative current collector, a commercially available conductive copper paint, diluted with ethanol.”
The team foresee a future where snap-together integratable painted battery tiles (working in conjunction with solar cells) create an energy-harvesting combination that would be hard to beat. As good as the hand-painted batteries are, she said, scaling up with modern methods will improve them by leaps and bounds. “Spray painting is already an industrial process, so it would be very easy to incorporate this into industry,” Singh said.
via Discovery News