Engineered bacteria could hold the key to recovering critical metals from electric vehicle (EV) batteries at the end of their uselife, in a new bio-based recycling process out of the University of Edinburgh.

Experts in sustainable biotechnology at the university, led by Professor Louise Horsfall, are exploring the concept, which sees bacteria used to extract metallic compounds from lithium-ion batteries. Once recovered and processed, these valuable elements – including cobalt, manganese, nickel, and lithium – could feed into a new UK-based supply chain for rechargeable vehicle batteries.

The Industrial Biotechnology Innovation Centre (IBioIC) is supporting the project to reach industrial capacity, using facilities at its FlexBio centre to refine the process in a larger bioreactor. Meanwhile, bacteria have been selected and engineered using the Edinburgh Genome Foundry, based at the University of Edinburgh, to ensure their effectiveness at scale.

Using a fermenter, bacteria are added to battery leachate – the liquid the remains after the initial processing stages – to stimulate a natural biological reaction.

During the process, the bacteria produce nano-sized particles of the metallic compounds, resulting in a sediment that can be separated and filtered out from the residual liquid. The current tests are being undertaken using material recovered from an EV battery previously used in a Nissan Leaf.

The latest research forms part of the wider Reuse and Recycling of Lithium-Ion Batteries (ReLiB) initiative, led by the University of Birmingham and funded by the Faraday Institution – the UK’s independent institute for electrochemical energy storage science, skills development, market analysis, and early-stage commercialisation.

According to the European Automobile Manufacturers’ Association (ACEA), battery electric vehicles accounted for 16.1% of total new cars between January and June 2023, making the UK one of the top ten European countries for EV sales.

As the market grows, so does the need for initiatives that can support the increasing supply chain pressures and deal with waste batteries as they come to the end of their useful lifetime.

In turn, as the reserves and resources of metals used in batteries decline, increasing amounts of raw minerals will reside in existing batteries themselves.

At the moment, the majority of metals used in EV batteries are imported – including cobalt, manganese, nickel, and lithium.

Generally, these metals are exploited from countries in Africa, where pressure for resources has driven mass conflict and depravation. Developing alternative recycling routes could open up a more sustainable UK-based pipeline of materials, lessening pressures on the incessant precious metals trade.

Professor Louise Horsfall, chair of sustainable biotechnology at the University of Edinburgh, said: “We often read about initiatives to reduce EV battery costs and improve their performance, but as the market for green transport grows, we also need to consider what happens to the technology once it is no longer fit for use. This project is about using cutting-edge sustainable biotechnology to find ways of tackling that challenge and, in turn, extract some of the most valuable metals that can go back into the sector at the early stages of vehicle production.

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“The work of the Edinburgh Genome Foundry to select the best performing bacteria, combined with the scale-up expertise we’ve been able to access via IBioIC, means we are heading in a positive direction towards turning the research idea into an industrial reality.”

Dr Liz Fletcher, director of business engagement at IBioIC, added: “This project is a great example of how biotechnology can be used to make everyday products and services like cars and transport more sustainable. No one wants to see lithium-ion batteries ending up in landfill, so it is important to explore different ways to repurpose and recycle them. The method being developed here has dual value – as well as being a petrochemical-free way of dealing with waste, it could also help to reshore the supply chain for rare metals and future battery manufacturing.”