Another technological approach is necessary to address this challenge for the industry. Direct recycling has potential for cost effective recycling of lithium-ion cathodes, which is demonstrated for NMC532 and NMC622 in this work.
In the first example, NMC 532 electric vehicle grade cells were faded to 80% of their original capacity. The cells were pulverized and cathodes captured and treated and packaged. Afterwards, in a manufacturing setting, 2.2 Ah cells were built using the recycled cathode and graphite. Recycled cathode demonstrated both performance and manufacturability like new material. In side by side cycle testing, both tallied 2,500 cycles at C/10 to reach 80% of original capacity.
In the second example, starting with faded cells, NMC 622 is similarly regenerated to original capacity and rate capability. Physical characterization of NMC622 before and after processing shows the treatment reverses ageing in the surface region of the electrode particles resulting in renewed performance.
These examples show the ease and flexibility of hydrothermal and calcination processes to restore electrochemical performance to NMC cathode materials. A comparable industrial process is alumina production from bauxite, which has a world-wide production over 60,000 tons and demonstrates the scalability and low cost potential for direct recycling. The development of distributed direct recycling services reduces both logistical and production costs relative to the current approach. Direct recycling technologies provide a viable foundation for the future waste management services for the lithium-ion battery market.