As application demands evolve, battery materials have gotten more complex, incorporating not only lithium, but higher nickel, manganese and cobalt content, while also including various dopants like aluminum or zirconium and stabilizing coatings. Processing all of these disparate components into battery cathode-active materials (CAM) often requires numerous complicated steps, from precipitation of metal sulfates to several grinding and regrinding cycles. Nano One Materials Corp. (Vancouver, B.C., Canada; www.nanoone.ca) aims to simplify the CAM supply chain by demonstrating that its single-step aqueous technology (the one-pot process) can be used for direct metal-to-CAM (M2CAM) conversion, eliminating sulfates from the process. “An issue with using traditional metal sulfates is that they are only about 22% metal, so you’re shipping a lot of extra weight in sulfates and water that aren’t really part of the active material. There’s a lot of wasted energy and extra greenhouse-gas emissions,” says Stephen Campbell, chief technology officer at Nano One.
In the one-pot process, all components are placed into an aqueous reaction to form a precursor slurry. The slurry is dried and fired, creating CAM nanocrystals. “Normally, when you make CAM in the conventional way, you end up with a polycrystalline agglomerate that is coated on the outside. In the battery, the agglomerates expand and contract, which fractures the particle and fractures the coating, allowing electrolyte into the inner surface of the material, resulting in a loss of stability,” explains Campbell. In the one-pot process, since the coating is mixed with the precursor from the beginning, firing yields individually coated crystals. “The coating comes to the surface of each crystal when it is fired, meaning that there is no additional process to put the coating on the crystal. It also means that each individual crystal is protected,” Campbell continues. This unique coated nanostructure gives these CAM particles improved durability when compared to traditional CAM particles. The M2CAM adaptation of the one-pot process has been demonstrated at laboratory scale, and Nano One is discussing scaleup with a number of collaborators across the supply chain.