A. Karati, P. Gargh, S. Paul, S. Das, A. Sarkar, P. Shrotriya, I.C. Nlebedim
Ames National Laboratory,
United States
Keywords: battery recycling, electrochemical lithium concentration, hydrogen production, BRAWS
Summary:
We will present a novel process, that relies on the Battery Recycling and Water Splitting (BRAWS) technology for full-value recovery of critical minerals and materials from battery waste streams using water as the only solvent. The BRAWS technology possesses both environmental and economic advantages, wherein lithium, graphite, cathode active materials, current collector and separator materials are recovered from end-of-life lithium-ion batteries, without the requirement for acids and other toxic solvents. Moreover, the process yields green hydrogen as the byproduct. The BRAWS technology overcomes the safety and negative environmental impacts of using harsh chemicals for recycling lithium-ion batteries, as well as the loss of materials, typical of traditional hydrometallurgical and pyrometallurgical processes. By efficiently recovering all battery components, our approach represents a paradigm shift from the current multi-chemical precipitation steps and complex high energy-consuming processes. It paves the way for a simple but efficient and safe process for full value recovery of embodied critical minerals and materials from waste batteries, while helping to advance the effort on hydrogen economy. The first step in the technology is electrochemical concentration of lithium on the anode of the batteries via our established cycling protocols. This is followed by the dismantling of the batteries to harvest the anode (typically graphite). By immersing the anode in water and using CO2 as feedstock, lithium is recovered as Li2CO3, green hydrogen is obtained as byproduct and the graphite is heat treated for reuse. Similarly, the other components of the battery are recovered in forms that can be reused. For example, the cathode materials can be relithiated using the conventional ceramic processing methods. Our process has been applied to batteries with different cathode materials including LCO, NMC and LFP chemistries. For the LCO cathode chemistry, we have demonstrated >90% yield in the recovery of lithium. We have also identified the conditions for controlling and maximizing lithium recoverability in NMC chemistry by correlating the cycling conditions with lithium concentrations as metallic lithium vs. lithium in the solid electrolyte interface. We have also demonstrated that the green hydrogen can be converted to ammonia without the evolution of any NOx gases. In conclusion, the BRAWS technology combines the benefits of the hydrometallurgical and direct recycling methods of value recovery from waste batteries, while overcoming their limitations. Unlike the state-of-the art processes, the BRAWS technology recovers all battery components (including lithium, cobalt and other cathode elements, copper, aluminum, and graphite), uses water as the only solvent, and creates green hydrogen, without the use of electricity and catalysts as in electrolyzers. Moreover, the use of CO2 as a feedstock offers a path for carbon negative recycling methodology. The BRAWS technology can be applied to a wide variety of batteries. When fully developed, the technology will create a practical path for both environmentally and economically sustainable battery recycling process.