|Scientists at Rice University have managed to design a lithium-ion
battery that can be painted on virtually any surface. The rechargeable
battery consists of spray-painted layers, each representing components
of a traditional battery.
The team spent numerous 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. The materials were
subsequently 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, while the
batteries provided a steady 2.4 volts.
The researchers confirmed the hand-painted batteries were quite
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.