Each layer is an optimized stew. The first, 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.
"We really do consider this a paradigm changer." It is not often that I get to start an article with such a statement, but the scientists at Rice university are convinced that their new paint-on Lithium battery is just such an advance. I can see this generating a whole lot of interest in Electric Vehicles and with buildings, roads and bridges. Since today I am under time pressure to meet an afternoon delivery, I will largely let the article speak for itself, although I agree with the scientists optimism. End decade perhaps, possibly a little sooner?
Paint-On Lithium Battery Can Be Applied to Virtually Any Surface
ScienceDaily (June 28, 2012) — Researchers at Rice University have developed a lithium-ion battery that can be painted on virtually any surface.
The rechargeable battery created in the lab of Rice materials scientist Pulickel Ajayan consists of spray-painted layers, each representing the components in a traditional battery. The research appears June 28 in Nature's online, open-access journal Scientific Reports.
"This means 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."
—- Singh said the batteries were easily charged with a small solar cell. She foresees the possibility of integrating paintable batteries with recently reported paintable solar cells to 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.
The Rice researchers have filed for a patent on the technique, which they will continue to refine.
If the components of a battery, including electrodes, separator, electrolyte and the current collectors can be designed as paints and applied sequentially to build a complete battery, on any arbitrary surface, it would have significant impact on the design, implementation and integration of energy storage devices. Here, we establish a paradigm change in battery assembly by fabricating rechargeable Li-ion batteries solely by multi-step spray painting of its components on a variety of materials such as metals, glass, glazed ceramics and flexible polymer substrates. We also demonstrate the possibility of interconnected modular spray painted battery units to be coupled to energy conversion devices such as solar cells, with possibilities of building standalone energy capture-storage hybrid devices in different configurations.