Rice University announced the development of a spray-on (in this case airbrushed) coating that stores electricity, a bit reminiscent of Stanford’s paper battery on which a coating could be applied to act as a battery. Mitsubishi has demonstrated a paint that could act as an extremely thin-film solar cell, but Rice’s technology shows promise.
Five layers comprise the various components of a lithium-ion battery and can seemingly be applied to almost any surface, including in one demonstration, a beer stein – showing an intoxicating range of possibilities.
But Pulickel Ajayan, materials science professor has more serious considerations. According to the University’s news. “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.”
The first layer, one of several “optimized stews” uses purified single-wall carbon nanotubes as the positive current collector. The second, cathode layer, contains lithium cobalt oxide, carbon and ultrafine graphite (UFG) powder in a binder solution. The third layer is a polymer separator, while the fourth, anode layer, is a mix of lithium titanium oxide and UFG in a binder, and the fifth is the negative current collector, a “commercially available conductive copper paint, diluted with ethanol.”
The least active of all the layers, the separator, caused the most problems, peeling off the substrate until PMMA, or polymethyl methacrylate, a transparent thermoplastic, was added to provide “stickiness.”
Neelan Singh, a Rice graduate student, led her research team in mixing all the stews, notes that the “battery” can be charged with a solar cell, and that performance is every bit as good as that for a conventional lithium battery. She is excited about integrating paintable batteries with paintable solar cells and creating an energy-making/storage system. The group even talks of being able to buy a kit for their creation at a typical home supply store and airbrushing it onto surfaces one wants to electrify.
Since spray painting is common in industrial settings, it would be reasonable to see this technique applied to manufactured products – say car parts or aircraft wings.
The University notes their research appears in Nature’s online, open-access journal Scientific Reports. Co-authors of the paper are graduate students Charudatta Galande and Akshay Mathkar, alumna Wei Gao, now a postdoctoral researcher at Los Alamos National Laboratory, and research scientist Arava Leela Mohana Reddy, all of Rice; Rice Quantum Institute intern Andrea Miranda; and Alexandru Vlad, a former research associate at Rice, now a postdoctoral researcher at the Université Catholique de Louvain, Belgium.