Cancelling cobalt to reduce health impacts of batteries is too simplistic

Lithium-ion batteries have witnessed an exponential growth world-wide and enabled products ranging from personal computers to electric vehicles. There is daunting evidence that vehicles powered by lithium-ion batteries have lower emissions than those powered by fossil fuels, when charged with renewable electricity. This advantage grows even larger now that batteries are increasingly produced at larger and larger scale, especially if those factories too are powered by renewable electricity.

But there is one critical sustainability issue often highlighted related to lithium-ion batteries: the material cobalt. It’s a cathode material in many lithium-ion batteries used in high-end electric vehicles. The human rights organization Amnesty has released reports about the harsh working conditions in artisanal cobalt mining in the Democratic Republic of the Congo, including child labor, abuse, and severe, sometimes lethal accidents.

While the harsh working conditions are undeniable and should be addressed, lithium-ion batteries also contain other key materials. In addition to lithium, nickel, and manganese, these include natural graphite and copper. In a recent life cycle assessment study focusing on health impacts, the researchers Rickard Arvidsson, Mudit Chordia and Anders Nordelöf from Chalmers University of Technology show that when all upstream processes of the battery cell are included, some other materials contribute equally or more than cobalt.

The researchers considered occupational accidents as well as emissions of toxicants, particles, greenhouse gases, and their subsequent health effects. These various health impacts can be compared and summed using the disability-adjusted life years (DALY) indicator, developed by the WHO for comparing different health hazards.

Nickel and copper come out worse than cobalt

The main contributor to the health impacts of this battery turned out to be nickel at 30%, mainly due to high emissions of metals and sulfur during its extraction. Second at 20%, comparable to cobalt, came copper, also due to metals and sulfur emissions at extraction. Accidents during artisanal cobalt mining in the DRC, together with emissions from cobalt extraction and refining, also contributed at about 20% of the total negative health impacts of the battery cell.

“In this assessment, all health impacts are treated equally, regardless of who is affected. The accidents in artisanal mining have clear victims – the workers. For emissions, health impacts rather affect the general population, especially for greenhouse gas emissions that cause climate change as well as subsequent floodings and diseases”, says Associate professor Rickard Arvidsson.

Naturally, such models of causes and effects, often employed in life cycle assessments, contain sources of uncertainty. One example is the time horizon within which impacts of emissions are considered, where shorter horizons give lower impacts, and vice versa. The current study is based on a 100-year time horizon, common in both life cycle assessment and environmental policy making.

The number of fatal accidents in artisanal cobalt mining is another important source of uncertainty. While being more direct than health impacts from emissions, fatal accidents face a particular methodological challenge: Contrary to non-fatal accidents, they cannot be monitored by self-surveys.

Efforts need to address all impacts

A palette of possible actions to lower health impacts of lithium-ion batteries can be recommended from the study. The researchers strongly recommend improving the safety standards in artisanal cobalt mining, with a particular focus on eliminating fatal accidents. However, this is not enough. Efforts need to go beyond cobalt and address also contributions from other materials.

“In contrast to a single-minded focus on substituting cobalt, we propose a set of actions for reducing health impacts across the whole lithium-ion battery life cycle: address toxic emissions caused during extraction of battery materials, improve occupational safety standards in artisanal cobalt mining, and increase the share of recycled materials in batteries. Together, these actions would unequivocally bring down the human health impacts of lithium-ion batteries”, says Rickard Arvidsson.

Foremost, reducing emissions from nickel and copper mining would lower health impacts considerably. In addition, increasing the use of recycled materials would avoid emissions from extraction of all primary materials, thereby lowering health impacts further. Taking a holistic life-cycle perspective on the health impacts of products such as batteries is crucial, even when there are direct and obvious health hazards, which understandably receive much attention.

 

The study

The scientific paper “Quantifying the life-cycle health impacts of a cobalt-containing lithium-ion battery” was published in The International Journal of Life Cycle Assessment.

Background – Cobalt mining and fatal accidents

The mining itself typically occurs in narrow tunnels dug using simple tools or by hand, normally without any support against collapses. The DRC currently provides 70% of the world’s cobalt supply, of which artisanal mining constitutes 20%. Because of this link between cobalt and negative social impacts, several organizations and researchers have urged for improved safety standards in artisanal cobalt mining. Some researchers have in fact advocated efforts towards removing cobalt from lithium-ion batteries entirely.

There is now an ongoing trend to lower the cobalt content in cathodes. The upcoming lithium-nickel-manganese-cobalt oxide battery that the researchers have studied has only one third of the cobalt content compared to the most common version of this battery type.

The number of fatal accidents in artisanal cobalt mining is an important source of uncertainty in the studies. While being more direct than health impacts from emissions, fatal accidents face a particular methodological challenge: Contrary to non-fatal accidents, they cannot be monitored by self-surveys. The main scenario of the study considered an expert estimate of 2.000 fatalities per year. Much lower estimates at slightly more than 60 fatalities per year also exist, based on media reports, but these arguably only cover a fraction of the fatalities. In fact, one witness claims to have personally seen roughly that same amount of people becoming buried in one single tunnel collapse. So, despite relying on a comparatively high estimate of artisanal mining fatalities, the assessment shows that cobalt is not the only significant contributor to the health impacts of the studied lithium-ion battery.

Background – Electric car growth

Sales of electric cars, including fully electric and plug-in hybrids, doubled in 2021 to a new record of 6.6 million, with more now sold each week than in the whole of 2012 (source). At the same time, the race to create the most environmentally and socially sustainable lithium-ion battery is on, causing the largest car manufacturers to commit to ethical sourcing of materials.