Selective bacterial separation of critical metals: towards a sustainable method for recycling lithium ion batteries

The large scale recycling of lithium ion batteries (LIBs) is essential to satisfy global demands for the raw materials required to implement this technology as part of a clean energy strategy. However, despite what is rapidly becoming a critical need, an efficient and sustainable recycling process for LIBs has yet to be developed. Biological reactions occur with great selectivity under mild conditions, offering new avenues for the implementation of more environmentally sustainable processes. Here, we demonstrate a sequential process employing two bacterial species to recover Mn, Co and Ni, from vehicular LIBs through the biosynthesis of metallic nanoparticles, whilst Li remains within the leachate. Moreover the feasibility of Mn recovery from polymetallic solutions was demonstrated at semi-pilot scale in a 30 L bioreactor. Additionally, to provide insight into the biological process occurring, we investigated selectivity between Co and Ni using proteomics to identify the biological response and confirm the potential of a bio-based method to separate these two essential metals. Our approach determines the principles and first steps of a practical bio-separation and recovery system, underlining the relevance of harnessing biological specificity for recycling and up-cycling critical materials.

Automated summary

Large scale recycling of lithium ion batteries (LIBs) is crucial for obtaining raw materials and implementing clean energy strategies. However, efficient and sustainable recycling methods for LIBs are yet to be developed. This study demonstrates a sequential process using two bacterial species to recover manganese, cobalt, and nickel, while keeping lithium in the leachate. The feasibility of manganese recovery from polymetallic solutions was also shown in a 30 L bioreactor. Additionally, proteomic analysis was used to investigate the selectivity between cobalt and nickel, confirming the potential of a bio-based method for separating these metals.