Printing batteries is the future of sustainable energy, according to engineers at PARC, the renowned California-based research and development company owned by Xerox. They recently debuted a cost-saving manufacturing process that could someday squeeze out all the parts of a battery at once—like striped toothpaste from the tube.

Today building a battery requires multiple steps. First, two separate machines fabricate electrodes by spreading pastelike layers of energy-storing materials on sheets of metal. After those sheets are dried and compressed, they are cut to size and sandwiched around a plastic separator to prevent electrical shortages. Last, the battery is packaged in a nonconductive material and filled with a liquid electrolyte that can carry charge between the electrodes.

The new battery-printing method simplifies that process. In April at a Materials Research Society meeting in San Francisco, PARC's Corie Cobb presented nozzles and materials that would enable manufacturers to print two thirds of a battery in one go. The two-headed printing nozzle can simultaneously extrude a lithium-ion cathode and a polymer separator. For now, until Cobb figures out a combination of materials that will not commingle during printing, a technician must add a graphite anode manually. But when all three components can be printed at once, Cobb and her colleagues estimate the triple-stripe process could reduce manufacturing costs by 15 percent. Still, battery makers have already shown interest in the double-stripe version. The prototype batteries perform as well as batteries made with the conventional process and the same materials.

Less expensive batteries are key to making more affordable electric vehicles and enabling electric utilities to purchase and store additional grid-stabilizing energy from variable wind and solar sources. In the long run, batteries could also be printed into custom shapes for new types of gadgets—instead of the rectangles and circles designers must work around today.