Lithium-ion batteries work by stacking active ingredients in layers. In your laptop and phone, the layers are stacked into a block, but a new process could make that seem quaint: spray-paint the necessary layers onto any surface like paint, to make an instant battery anywhere.
Scientists at Rice University tested out different paints until they found a set that could work as the necessary components for a lithium-ion battery: two current collectors, a cathode, an anode, and a polymer separator. The layers can be airbrushed on and the resulting battery is fully rechargeable. To test it out, researchers put it on steel, glass, ceramic bathroom tiles, and (why not?) a beer stein. Batteries on the bathroom tiles were able to send out a steady 2.4 volts--enough to power light-emitting diodes that spelled out "Rice" for a full six hours.