Battery electrolytes are liquids that must be sealed inside rigid casings, a design that limits battery shapes and raises safety concerns about leaks. A relevant innovation engineered by researchers from The University of Texas at El Paso and U.S. Sandia National Laboratories could free engineers from the constraints of standard rechargeable battery sizes and allow energy storage to be built directly into the devices the batteries power.

Design restrictions are eliminated by the 3D printing of gel polymer electrolytes by combining a light-curable resin with a lithium-based liquid electrolyte, then hardening it layer by layer via the vat photopolymerization process. As reported in Communications Engineering, the printed material performed on par with electrolytes made by conventional methods, reaching ionic conductivities of up to 3.4 × 10⁻³ siemens per centimeter, approaching the performance of the liquid electrolytes it is intended to replace.

The fabrication process was performed in ordinary laboratory air rather than inside a sealed, oxygen-free chamber and the material maintained its performance. To showcase the design freedom the method offers, simple discs, an open honeycomb lattice and a solid 1 centimeter cube were also 3D printed. The technology underscores how future batteries could be shaped to fit a wearable, a medical device or an aerospace part rather than forcing the device to accommodate the battery.

"For years, the shape of a battery has dictated the shape of the device it powers," said the researchers. "We are showing that you can print a high-performing electrolyte battery component with any shape and place it almost anywhere you want. That changes what designers are able to imagine."