Researchers develop paintable battery: Technique could turn any surface into lithium-ion battery (w/ Video)

Rice researchers develop paintable battery
An electron microscope image of a spray-painted lithium-ion battery developed at Rice University shows its five-layer structure. Credit: Ajayan Lab/Rice University

( -- Researchers at Rice University have developed a lithium-ion battery that can be painted on virtually any surface.

The rechargeable 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 today 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 a 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."

Lead author Neelam Singh, a Rice graduate student, and her team spent painstaking hours formulating, mixing and testing paints for each of the five layered components – two current collectors, a cathode, an anode and a polymer separator in the middle.

Rice researchers develop paintable battery
Conventional lithium-ion batteries wrap active layers into a canister or other portable container. But Rice University researchers have found a way to paint those layers onto any surface, which opens up the possibility of turning those surfaces into storage devices. Credit: Neelam Singh/Rice University

The materials were airbrushed onto ceramic bathroom tiles, flexible polymers, glass, stainless steel and even a beer stein to see how well they would bond with each substrate.

In the first experiment, nine bathroom tile-based batteries were connected in parallel. One was topped with a solar cell that converted power from a white laboratory light. When fully charged by both the solar panel and house current, the batteries alone powered a set of light-emitting diodes that spelled out "RICE" for six hours; the batteries provided a steady 2.4 volts.

Rice researchers develop paintable battery
A beer stein served as an able substrate for a paintable battery developed at Rice University. (Credit: Jeff Fitlow/Rice University)

The researchers reported that the hand-painted batteries were remarkably consistent in their capacities, within plus or minus 10 percent of the target. They were also put through 60 charge-discharge cycles with only a very small drop in capacity, Singh said.

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.

"The hardest part was achieving mechanical stability, and the separator played a critical role," Singh said. "We found that the nanotube and the cathode layers were sticking very well, but if the separator was not mechanically stable, they would peel off the substrate. Adding PMMA gave the right adhesion to the separator." Once painted, the tiles and other items were infused with the electrolyte and then heat-sealed and charged.

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. Singh said they are actively looking for electrolytes that would make it easier to create painted batteries in the open air, and they also envision their batteries as snap-together tiles that can be configured in any number of ways.

"We really do consider this a paradigm changer," she said.

Explore further

New lithium ion battery strategy offers more energy, longer life cycle

Journal information: Nature , Scientific Reports

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Jun 28, 2012
Wow. If that has any sort of durabilty I'd like to have those in the bathroom or maybe even underneath the wallpaper - with an ambient light solar cell layer spray-painted on top.

Soaking up energy during the day via solar cells and storing it in the 'environment' would be just a very cool way to live. Probably wouldn't power a washing machine or an oven, but for small appliances (TV, lighting, fridge, recharging your phone, etc.) that might be enough. (and can I have LEDs showing me the charge state of my walls?)

One question that needs to be adressed, though, is what to do with this stuff at the end of its lifecycle. Can it be easily recycled?

Jun 28, 2012
This is six years old stuff already and we can read similar reports about it every year. But I still didn't see any practical application of it - IMO it's time to think, why is it so...

Jun 28, 2012
AtlasT: maybe the solar cell battery combination is a real achievement.

Jun 28, 2012
Who will care about it and who will cover the buildings with complex layers containing toxic chemicals, when the cold fusion batteries will be miniaturized and ready to use during day or night? It's not so easy to develop durable protective paint, which doesn't require expensive renovation every ten years. The probability that such paint will serve as a reliable solar cell, not to say about battery is the product of many low probabilities, i.e. even way lower probability.

Jun 28, 2012
Yet another zephir clone.....

Jun 28, 2012
One square foot tile laid on a roof, solar cell facing up, battery painted on the bottom, powering a single tiny Zenon LED all night long for somebody in an impoverished country. That's enough light to keep people from stumbling around in the night, and a couple more would allow reading at night.

Now to find a good substitute for the lithium...

Jul 01, 2012
Not covered in the article are costs. How does the cost of producing painted batteries compare to currently available batteries and will this be competitive? Will this provide a more economical process for manufacturing batteries?

Regardless, I applaud the achievement. Even if it's not marketable/economic now, it could very easily lead to some actual better products.

Jul 01, 2012
UV protection layer, photovoltaic layer, battery layer, insulation layer, structural layer, interior wear layer and pressure seal = inflatable orbital or martian habitat.

See this is what AGW is good for. This tech wouldnt be developed without it.

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