A new printing technology invented by Xerox promises to have the ability of packing more energy into EV batteries. The invention involves the printing of a striped pattern of energy storage materials and highly conductive materials. The resulted electrodes are thicker than conventional ones, but can increase the energy stored in a battery by 10 to 30 percent.
Unlike classic battery electrodes which are applied in the form of slurry to metal foils, these ones have their thickness limited by the rate at which lithium ions diffuse out of the material to reach the electrolyte. Both the electrode material and the highly conductive metal is forced through a flat print nozzle, which aligns them and draws hair-thick alternating stripes with them.
Because the lithium ions have more paths to travel along due to the conductive material, the battery can bear higher discharges in a shorter time, just like supercapacitors do. This happens because the electrodes are thicker, and you need fewer layers of them, unlike in a classic lithium ion battery, of which half is made up of materials that don’t store energy, with every layer requiring a metal foil and polymer film as separators.
The technology for these Xerox batteries is already used in commercialized products. Some solar cells are being printed thin silver lines, and the technique is only being adapted for batteries, with a few issues to overcome.
One of them is that the researchers have to use compatible electrode materials, conductive materials and electrolytes. Metal-air batteries are also in their focus as a possible application.