Carbon emissions from the lithium-ion battery supply chain could be cut by a third by 2060, but only by combining cross-regional cooperation with regionally tailored circular economy policies, a study in Nature has concluded.

Lithium-ion batteries are a crucial decarbonisation tool that enables renewable energy integration and cutting fossil fuel reliance. However, their production process – from mining and refining to cathode synthesis – generates significant carbon emissions that could outweigh their in-use benefits.

A group of researchers, based in China, the US and Canada, carried out a modelling study using data captured between 2018–2022 – a critical phase of rapid expansion for the global lithium-ion battery supply chain. They used this data to estimate the carbon emissions of the entire lithium-ion battery supply chain, spanning several countries – including Australia, Chile, China, South Korea and parts of Europe.

Although previous studies have evaluated greenhouse gas emissions across the lithium-ion battery industry, a comprehensive examination of mitigation pathways across the entire production life cycle, accounting for policy, trade and technology, has not been carried out, according to the researchers.

Overall, the largest share of emissions came from mining, which was responsible for 39% of the overall carbon emissions of battery production. However, the researchers also discovered a ‘value-emission paradox’ whereby the portions of the supply chain generating the least revenue, produced higher levels of carbon emissions.

In the case of mining, this only contributes 19% of the total value of the battery, while, in contrast, producing cathodes for the batteries contributes 43%, but just a third of the total emissions.

The researchers also carried out a scenario analysis to explore decarbonisation pathways, including varying recycling intensities and environmental, technological and trade policies at both a regional and cross-regional level. These simulations showed that, although recycling-focused policies can be effective, their impact was highly context dependent, and consumer-oriented approaches, while globally beneficial, could increase emission intensity in resource-exporting regions.

The most substantial decarbonisation, they concluded, was realised only by integrating several policy levers: combining cross-regional cooperation on technology and trade with tailored, regional policies. With this approach, global emissions reductions of 36% could be achieved by 2060, compared with 16% through consumer-oriented recycling alone.

Paul Anderson, an inorganic and materials chemist at the University of Birmingham and principal investigator of the Faraday ReLiB (Recycling and Reuse of EV Lithium-ion Batteries) project, says that while the conclusions of the study are not especially new, the comprehensive nature of the study and richness of the data make the findings ‘quite authoritative’.

‘We’re not going to be able to dig enough stuff out of the ground to make [lithium-ion batteries] work anything like as quickly as we want; it’s going to be very important to have recycling as an integrated part of this, to make it work environmentally, and also in terms of time and … maybe make it work at all.’

However, Anderson says one of the elements missing from the study was that it used greenhouse gases as the only indicator of environmental sustainability. ‘The biggest wins actually might be in the ecotoxicity categories,’ he explains. ‘Because the industry is in its infancy [and] the recycling is developing, there could be quite an ecotoxicology “sting in the tail”, with firstly some of the ways [we make] batteries, and the compositions and the chemistry we make , and also some of the recycling and cleanup processes, because some of those use quite a lot of energy themselves, and produce quite a lot of chemical waste.’

‘All the evidence is saying that we must circularise the economy in this, firstly to make it work, [and] secondly, to reduce the carbon emissions,’ he adds. ‘But we should also be looking at the broader environmental footprints of, firstly, the batteries that we make and, secondly, the processes that we are going to rely on to and all of that is incredibly difficult.’