Jinzhao Fu

Powder-based solvent-free manufacturing of electrodes for Li-ion batteries represents an emerging and promising technology in electrode fabrication. This method involves a two-roll powder calendering process, where electrode powder materials are compressed onto a current collector to form electrodes with desired properties. The calendering or compaction of dry powders onto a current collector is a crucial step in solvent-free electrode manufacturing, significantly impacting the microstructures, mechanical properties, and electrochemical performance of the produced electrodes. In this article, we investigate the compaction characteristics of electrode powders to gain insights into their behavior. A powder-on-current collector calendering model is developed based on Johanson's rolling theory of granular solids. This model enables us to infer the underlying calendering parameters essential for the solvent-free manufacturing of Li-ion batteries. To validate the model, we compare it with experimental calendering results, utilizing measured powder properties and roll design parameters as inputs. This approach offers a comprehensive understanding of the effects of roll geometries, particularly roll diameter, and various equipment design parameters on final electrode properties. Such insights have not been thoroughly explored in the emerging field of solvent-free battery electrode manufacturing, thereby contributing to advancements in this area.

As the economy started to recover from the COVID pandemic, the price of Li₂CO₃ skyrocketed to its highest. This situation has aggravated concerns about the supply chain for lithium-ion batteries (LIBs). Recycling spent LIBs is a potential solution to alleviate the bottleneck of the supply chain and prevent environmental pollution, and has attracted lots of attention. However, lithium recycling is generally disregarded because of the complex recycling process and its low recycling efficiency. Here, in this work we developed a sustainable lithium recovery process, which can selectively leach and recover lithium with formic acid before recycling valuable metals. With the reported method, lithium can be 99.8% recovered from layered oxide cathode materials with 99.994% purity. In addition, this lithium recovery process is affordable, compared to the typical hydrometallurgical process, by saving 11.15% per kilogram of spent LIBs. Therefore, this research provided a new solution to eliminating the effects of lithium ions on valuable metal separation and the co-precipitation reaction and precluding the influence of other metal ions on lithium recovery. This simplified lithium recovery process provides new opportunities for sustainable recycling of LIBs and economical restoration of the lithium supply chain.