BY JON EVANS
Battery sustainability can mean many different things. New battery passports – set to go live in 2027 – should help to bring clarity to the area, by rating technologies according to a list of ‘sustainability indicators’. Jon Evans reports
The global lithium-ion battery supply chain is set to grow by almost 30% a year until 2030, according to McKinsey Battery Insights to reach a value of more than US$400bn and a market size of 4.7TWh. Batteries, particularly lithium-ion batteries, are increasingly required to power everything from smartphones to electric vehicles - and to store the growing share of energy produced by renewables.
But growing demand also brings a problem. More than 50 critical minerals and other raw materials make up the components of a lithium-ion battery, of which the most important are the two electrodes and the electrolyte that separates them. In a lithium-ion battery, the cathode is made from a combination of lithium and several other elements, often nickel and cobalt, while the anode is made from graphite. The electrolyte is usually a lithium-based salt dissolved in an organic solvent. And yet for many of these critical minerals and materials, including lithium, nickel, cobalt and graphite, this rapid growth in demand may be difficult, if not impossible, to meet.
‘It is clear that mineral production for batteries is going to need to ramp up enormously in the next 10–20 years,’ says Graham Lee of the Global Battery Alliance (GBA), a private-public collaboration of battery manufacturers, mineral suppliers, academics, governments and technology providers.
The obvious solution is to make lithium-ion batteries more sustainable. But what exactly does that mean?
A sustainable battery might, for example, use smaller amounts of critical minerals. This is especially important where supply could be restricted if global production capacity is insufficient or if production and processing of the mineral is concentrated in a small number of countries.
China, for example, currently dominates the production of graphite and is the leading processor of both lithium and cobalt (C&I, 2024, 88 (6), 22), while over the past few years Indonesia has become the leading producer and processor of nickel. China has already shown a willingness to restrict exports of certain critical minerals where it is the leading producer, such as gallium and germanium, while Indonesia recently introduced measures to ban the export of unprocessed nickel ore, with the aim of boosting its own battery industry. Much of the world’s cobalt, meanwhile, comes from the Democratic Republic of Congo, where there are major concerns about the environmental damage caused by cobalt mining and the use of child labourers.
In this case, sustainability means finding ways to meet the growing demand for batteries without running out of raw materials, causing environmental damage or exploiting local populations. Over the short term, the battery sector is addressing this by adopting strong environmental and social safeguards and management systems. But a more long-term solution would be to swap some of the critical minerals with more widely available and less problematic materials.
Sustainability can mean finding ways to make batteries safer and more environmentally friendly, again by using alternative materials. The electrolyte is a particular focus here, because the organic solvents in which the lithium salt is dissolved are toxic and also potentially flammable. Sustainability can also mean developing more energy efficient ways to produce batteries, thereby reducing the amount of greenhouses gases generated during their manufacture. It can even mean developing batteries that hold more charge and are better at retaining their capacity over time. If batteries hold more charge, fewer will be required to store and generate the same amount of energy. And if they can retain their capacity for longer, they won’t need to be replaced as often, which tends to happen when their capacity falls by more than 20%.
Sustainable advances
Much effort is being expended by both industry and academia on all these different approaches to sustainability. Already, nickel is replacing cobalt in the latest battery cathodes, due in part to the various issues surrounding the latter’s mining. Meanwhile, silicon could soon replace graphite as the anode material of choice, because not only is silicon more abundant and widely available than graphite but it can also store more lithium ions and therefore more charge. Whereas in graphite six carbon atoms are required to host each lithium ion, a single silicon atom can host four lithium ions. This means that a silicon anode can theoretically store up to up to 10 times more energy than a graphite anode. But this ability to host lots of lithium ions has its downside because it causes the silicon anode to expand to up to three times its original size, which ends up damaging the anode and ruining performance.
Over the past few years, several companies have developed solutions to this expansion problem and are now commercialising silicon-based anodes. US company Sila, for example, has developed a silicon-based anode material in which silicon atoms are embedded in a framework of carbon atoms to accommodate any expansion. The company offers this anode material, Titan Silicon, as a drop-in replacement for graphite anodes and claims it can increase the energy capacity of lithium-ion batteries by 25%; in future, this could rise to 40%.
Another US company, Amprius Technologies, has developed an entirely silicon anode, consisting of a forest of silicon nanowires, with the gaps between the individual nanowires providing enough room for expansion. As it’s composed solely of silicon, Amprius claims its anode can reach close to the theoretical maximum for energy storage of 10 times more than graphite. But because these silicon nanowires have to be deposited during the battery production process, it’s only offering this silicon anode within its own battery cells, rather than as a general, drop-in replacement for graphite anodes.
A whole host of other approaches for improving the performance of lithium-ion batteries have yet to leave the laboratory. Examples include lithium-sulfur batteries, which use lithium metal as the anode and sulfur as the cathode – and boast a theoretical energy capacity eight times greater than conventional lithium-ion batteries. There are also lithium-air batteries, which also use a lithium metal anode but with a porous, air-filled cathode. Here, the lithium ions react with oxygen in the air to form various lithium oxides, which means lithium-air batteries can potentially store up to five times more energy than conventional lithium-ion batteries.
Various other novel materials and designs are being explored for almost every component of lithium-ion batteries, including the current collector that directs the electrons released from the cathode to the external circuit and the separator that prevents them travelling through the electrolyte. Several research groups are looking to develop some of these components from natural materials, such as anodes made from burnt rice hulls or chitosan from crab shells. Efforts are also under way to replace liquid electrolytes with solid ones that are less toxic and flammable.
Other companies and research groups are moving away from lithium entirely, by developing batteries that work with ions of more abundant and easily obtainable elements such as sodium, derived from seawater. Sodium-ion batteries are currently the most advanced, with several versions being developed and commercialised by companies like Natron Energy in the US and Altris in Sweden. Following on behind are a range of other novel battery technologies that use more abundant elements, including aluminium-ion batteries, zinc-sulfur batteries and oxygen-ion batteries.
Finally, researchers are also developing efficient processes for making batteries easier to recycle. If critical minerals can be recovered from old batteries, this will reduce the amount that needs to be mined, with all the associated benefits. According to a recent paper in Nature Communications (2025, 16, 988), current processes for extracting lithium, nickel, cobalt, copper, manganese and aluminium from old batteries generate less than half the greenhouse gases of mining and processing these metals, as well as using about one-fourth of the water and energy.
‘We’re forecast to run out of new cobalt, nickel, and lithium in the next decade,’ says William Tarpeh, Assistant Professor of chemical engineering at Stanford University and senior paper author. ‘For a future with a greatly increased supply of used batteries, we need to design and prepare a recycling system today, from collection to processing back into new batteries, with minimal environmental impact. Hopefully, battery manufacturers will consider recyclability more in their future designs, too.’
So there are multiple options for making batteries, especially lithium-ion batteries, more sustainable, many hitting more than one sustainability goal. Some, however, are mutually exclusive. Sodium may be much more abundant than lithium, but sodium-ion batteries currently store less energy than lithium-ion batteries.
Also, although these novel options all produce batteries that are in some way more sustainable than a conventional lithium-ion battery, how do they compare with each other? Is a battery that uses more abundant elements, such as a sodium-ion battery, more sustainable than a version of a lithium-ion battery that can store much more energy, such as a lithium-air battery? And what about a lithium-ion battery with a solid electrolyte and electrodes made from natural materials, or one that is produced from recycled materials?
Measuring success
What is needed is a way of comparing the sustainability of different batteries and battery technologies, which is where the concept of a battery passport comes in. Battery passports are mentioned in the new EU Batteries Regulation and various other countries, including China, are beginning to show an interest. The idea is that every newly manufactured battery would come with its own passport specifying all the sustainability-relevant data, including where the battery was produced, what battery chemistry and materials it employs, details of environmental and social safeguards, and various performance metrics such as energy density.
The passport for each battery would be virtual, with all the information held in the cloud, and accessed by scanning a QR code on the side of the physical battery. There would also be an overall sustainability score for each battery, allowing different batteries to be compared. Exactly how a battery passport might work is currently being explored by the Global Battery Alliance (GBA), which was set up in 2017 to help establish a sustainable battery value chain.
So far, the GBA has conducted two battery passport pilot studies. The most recent took place in 2024 and involved ten consortia of battery manufacturers and supply chain companies. Each consortium produced its own battery passport. These efforts are designed to establish a framework for a viable battery passport, which would then be implemented by others. ‘First and foremost, the GBA’s role is about setting rules and norms defining this vision of how exactly a battery passport for the battery mineral supply chain should look like, how sustainability performance should be measured, how data should be exchanged, how we can set up mechanisms to ensure the data is trustworthy,’ says Lee, who is head of the battery passport programme at the GBA. ‘It’s that rule-setting function that is really core.’
Much remains to be finalised, including the full list of sustainability indicators, but the plan is for the battery passport to go live in 2027. And when it does, Lee hopes that it doesn’t just allow the sustainability of different batteries and battery technologies to be compared but acts as a spur for the further development of sustainable batteries.
‘What we hope is that, by meas-uring sustainability performance, it will incentivise companies to adopt better sustainability management systems.’
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