We've covered paint-on
solar cells previously - now boffins at Rice University have created
spray-on batteries; a development easily adapted to current commercial processes
and one that could revolutionise the battery industry.
Batteries created using the paint-on process will allow for a plethora of new design and integration possibilities for storage
devices says Pulickel Ajayan, a Professor in mechanical engineering, materials
science and chemistry at Rice.
The battery consists of five layers - two current collectors, a cathode, an anode and a polymer separator
- each of which are sprayed on.
to a press release from the University, the first layer is a positive current
collector made of high purity single-wall carbon nanotubes with carbon black particles dispersed in
The second is the cathode; made with lithium cobalt oxide, carbon and
ultra-fine graphite powder mixed in a binder solution. The third is a polymer separator paint
containing Kynar Flex resin, Poly methyl methacrylate and silicon dioxide dispersed in a solvent.
The fourth layer acts as the anode and consists of lithium titanium oxide and
ultra-fine graphite in a binder solution. The final layer is the negative current collector,
made with a conductive copper paint already commercially available that is diluted with ethanol.
In an experiment, a battery bank was created using bathroom tiles
as a substrate. One battery was topped with a solar cell and using a laboratory
light as an energy source, once fully charged the battery bank powered 40 light-emitting diodes (LEDs)
for six hours. After 60 charge and discharge cycles, the paint-on batteries only
experienced only a small amount of storage capacity loss.
The researchers have filed for a patent on their invention and will
continue to refine the technology and associated processes. A complete technical
description of the spray-on battery appears in Nature.com's Scientific
The researchers see the potential of integrating their paintable battery
technology with paint-on solar cells. Some of the spray/paint-on solar cell
technology we've covered in the past includes Sun-Believable