Dr Virginia Echavarri-Bravo: using microbes to upcycle metals from lithium ion batteries

Minerals are considered critical if they are vital for modern technologies and economies to function, but are at risk of supply chain disruptions. Which minerals are classified as critical varies between countries. In the UK, the critical minerals list from 2024 includes many of the metals contained in batteries, such as lithium itself, cobalt, manganese and nickel.

Electrified transport and many digital devices rely on lithium-ion batteries, which require critical minerals. There are variations in the combination of metals within a lithium-ion battery, but the metals most commonly used are lithium, cobalt, phosphate, manganese, nickel and aluminium. The battery in the device you’re using to read this article, for example, is most likely a lithium cobalt oxide (LCO) battery.

Environmental and social implications of critical mineral mining

Cobalt and the DRC

A highly prominent example is the mining of cobalt in the Democratic Republic of the Congo (DRC). The DRC is the biggest exporter of cobalt; in 2024, it was reported to have supplied 76% of the world’s cobalt. Mines in the DRC rely heavily on modern slavery, and child labour is prevalent. Those living in villages surrounding mine sites suffer severe health complications from exposure to toxic chemicals; women experience a greater risk of birth defects and reduced fertility. Not only this, but in areas surrounding mine sites, crop yields are drastically reduced, and water sources have become toxic, contaminated with high concentrations of metals. 

Electric vehicle manufacturers and consumer-facing technologies profiting off this cobalt take no responsibility for the lives of the people in the DRC and continue to claim that their cobalt supply chains from the DRC are fully audited and compliant with international human rights and environmental sustainability practices (Kara, 2025).

A report produced by the collaboration of University professors in the UK and the DRC shed light on the harsh reality of these mine sites. It described how 87.8% of respondents began working as artisanal miners due to the lack of any alternative means of survival, how $3.28 was the average daily income, with heavy gender-based bias, males: $3.52; females: $1.84 and how almost two-thirds of respondents reported a chronic illness or ailment (Kara, 2025). 

Water 

Mining has a severe impact on water quality in freshwater sources worldwide. When large amounts of rock are excavated from the earth during mining, sulphide minerals in the rock react with water and oxygen to produce sulphuric acid. Acid is carried off the mine site by rainwater or surface drainage and deposited into nearby streams, rivers, lakes, and groundwater (Hancock, 2016). This leads to a drastic reduction in biodiversity in nearby water sources, with only bacteria adapted to extreme environments able to survive. 

This is exacerbated by metal leaching. Metals from the mine site leach into local waterways and build up in toxic concentrations. Chemical agents used to separate target minerals can also leach into local waterways. 

Future considerations - Manganese

While not a problem at the moment, growing critical mineral demands mean there is risk of deep-sea mining for manganese being authorised. 

Manganese is found in nodules, small lumps of concentrated minerals, on the sea floor. Some companies wish to harvest this through a destructive process called deep-sea mining. This involves lowering gigantic machines to the seafloor to scoop up mineral deposits, pumping the mineral to a ship on the surface through large tubes and dumping out waste material like seawater and sediment back into the ocean, creating sediment plumes. 

This is expected to cause major, potentially irreversible, environmental damage to deep-sea ecosystems. Ensuring we have alternative methods to meet our growing critical mineral demands, such as for manganese, is therefore crucial to prevent the authorisation of such destructive practices. 

Critical mineral supply chain risks

The UK and the EU have limited control over the critical mineral supply chain due to their lack of domestic resources. This dependency leaves both regions vulnerable, as they rely heavily on imports for the essential materials needed for advanced technologies and manufacturing.

Recycling spent batteries 

The ongoing humanitarian crisis in the Democratic Republic of Congo, the severe environmental impacts of mining, and the potential for further ecological destruction highlight the urgency of addressing critical mineral dependence. Combined with the political and supply chain vulnerabilities faced by the UK and EU, these factors make it essential to recover valuable metals from spent lithium-ion batteries and other end-of-life technologies. Enhancing metal recovery and recycling is vital if the UK and EU are to reduce reliance on unsustainable mining practices and achieve net zero by 2050.

At the moment, it is very difficult to recycle the metals from spent batteries in an efficient and sustainable manner. Conventional recycling methods involve the use of organic compounds derived from petrol and other harsh solvents and require very high temperatures. They produce hazardous waste and are highly energy-intensive

Dr Echavarri Bravo’s research

Dr Virginia Echavarri-Bravo is a Postdoctoral Research Associate in the Horsfall group in the School of Biological Sciences, the University of Edinburgh. The group investigates methods for recycling and upcycling critical and strategic metals contained in spent lithium-ion batteries, as part of the ReLiB project, funded by the Faraday Institution.

Her recently published work, together with colleagues Marsland, Jensen, Kirk and supervisor  Louise Horsfall, showed the selective recovery of manganese from spent lithium-ion batteries, using a genetically engineered bacterial strain of Shewanella oneidensis. The manganese was recovered in a low-energy process at room temperature as uniform, spherical microparticles of manganese carbonate. This is useful, as manganese carbonate is the precursor material for making new batteries.

“If we can upcycle the metals rather than just recycle them, it’s better because we are adding value to the recycling process.”

Why is this biological approach better than conventional methods?

These reactions all occur at room temperature, which can save energy costs and be more sustainable than conventional methods. Moreover, these biological reactions do not produce toxic waste. Both these aspects make this technique more environmentally friendly, although the definitive answer will be given through the development of life cycle impact assessments or sustainability assessments. These analyses can be complex, as currently not enough quality data is available.

Dr Echavarri-Bravo is now looking at scaling up the technology, so it can eventually be used on a commercial scale.

“We have successfully recovered manganese in a 30L vessel and we are confident our technology could be adapted to recover lithium at the same scale. The recovery of cobalt and nickel has been demonstrated at 6L scale. But battery metal content can be very variable, so we need to continue and even widen collaborations to demonstrate the flexibility of the technology.”