Batteries with iron, lithium and even sodium at their core might be on the road as soon as this year, but manufacturers won't stop there: Solid-state technology, sulfur and silicon will define electric vehicle batteries in the late 2020s and beyond.

. . Battery-makers and EV producers are responding to high metal prices with a host of new chemistries. Batteries is a four-part series examining the trend. Metal supply concerns push EV makers to new battery chemistries Automakers go vertical, invest in mines for battery metals Emerging new chemistries create trade-offs in cost, performance EVs to use silicon, solid-state for next-generation batteries .

EV makers are already responding to high battery metal prices by changing anode and cathode chemistries to rely on cheaper, more common elements. The batteries of the future might get beyond the liquid chemistries of the early 2020s to rely on solid-state technology and swap out graphite in the anode for sulfur or silicon.

"In terms of what our expectations of changes are, it's certainly greater diversity across the chemistries," said Max Reid, a senior research analyst at Wood Mackenzie who specializes in EVs and the battery supply chain.

Shortages to come

Passenger EV sales are expected to approach 30 million units by 2027 and continue growing, S&P Global Commodity Insights analyst Alice Yu said in an April report.

Amid higher demand for EVs, manufacturers will be pushed to change the mineral inputs of their batteries further and adopt unique chemistries as they encounter supply shortages, high prices and continued pressure from consumers to increase the driving range of EVs, Reid said.

These novel chemistries will usher in a new generation of EV batteries with higher energy density, fewer safety concerns and less exposure to volatile supply chains, industry experts told S&P Commodity Insights. EV batteries are now headed toward cathode chemistries with less nickel and might even employ solid-state technology.

Fueling these changes are concerns about dependence on a small set of countries for minerals such as cobalt used in EV battery cathode and anode manufacturing.

"We can talk about the [well-trodden] issues of concentration throughout the supply chain, whether that be concentration in the upstream with limited resource availability amongst a few countries, [or] concentration in the midstream," said Reed Blakemore, deputy director with the Atlantic Council Global Energy Center. "That's where a lot of the oxygen in the room is taken up by the conversation around China's dominance over mineral processing."

Silicon-based anodes

Cathodes are not the only part of the EV battery cell getting a makeover.

Some companies, such as Sila Nanotechnologies Inc. in California, are developing silicon-based anodes to replace the graphite commonly used today. Carmaker Mercedes-Benz Group AG announced in May 2022 that it will use Sila's anodes in select vehicles by mid-decade.

As with nickel, graphite is sourced through a concentrated supply chain. For EV producers wanting to cut their greenhouse gas emissions, such as BMW Group, there is the added challenge of synthetic graphite's high carbon intensity. Production of the material, which can be cheaper than natural graphite, relies on petroleum coke and other fossil fuels.

"Compared to graphitic carbons, silicon has nearly an order of magnitude higher [energy] capacity," John Vaughey, senior chemist at the Argonne National Laboratory, and Brian Cunningham, program manager at the US Department of Energy, wrote in a report for the Silicon DeepDive Program, which is focused on developing an effective silicon anode. But several problems currently limit silicon's use in commercial cells, including anode expansion and high reactivity that can make batteries unstable, Vaughey and Cunningham said.

Using refined silicon materials known as nano-composite silicon reduces the weight of cells, improves battery range and shortens charging time, according to Sila. The company said this material is different from a pure silicon anode, which can come with chemical reactivity issues that have hindered its use today.

Major car manufacturers such as Stellantis NV are also exploring the possibility of swapping nickel-based cathodes for lithium-sulfur ones. The company announced May 25 that it will invest in LytEn Inc.'s lithium-sulfur battery technology.

"Unlike traditional lithium-ion batteries, LytEn's lithium-sulfur batteries do not use nickel, cobalt or manganese, resulting in an estimated 60% lower carbon footprint than today's best-in-class batteries and a pathway to achieve the lowest emissions EV battery on the global market," Stellantis said in the announcement. "Raw materials for lithium-sulfur batteries have the potential to be sourced and produced ... in North America or Europe, enhancing regional supply sovereignty."

Solid-state batteries

Beyond swapping out minerals, EV makers are looking toward changing the physical state of metals in a battery to cut back on mineral demand, increase battery lifespan and improve energy density in the long term.

A solid-state battery (SSB) employs a solid electrolyte rather than the liquid electrolyte commonly used in conventional cells. This can make the final battery product lighter, more stable and better at holding energy. Lithium SSBs could have a maximum energy density potential of up to 480 watt-hours per kilogram, compared to common lithium-ion batteries' forecast maximum of 300 Wh/kg by 2025, according to the International Energy Agency (IEA).

The primary obstacle to widespread SSB adoption is scaling up production from a lab setting to an industrial scale, according to the IEA. "After a robust and cost-effective scale-up process is found, the design of electric cars equipped with [all SSB] would take between three to five years," the agency wrote in a 2021 flagship report.

US-based Solid Power Inc., a developer of SSB technology for EVs, is working on an SSB that pairs a nickel-manganese-cobalt cathode with a silicon-based anode and a solid sulfide electrolyte. QuantumScape Corp., another US battery company, is developing its own SSB that uses a ceramic electrolyte with a lithium-metal anode.

Japanese carmaker Nissan Motor Co. Ltd. is targeting 2028 for the inclusion of SSBs in its cars, and Honda Motor Co. Ltd. said it aims to begin the rollout of SSB-powered EVs sometime in the second half of the 2020s.

"If researchers and manufacturers find the solution to mass producing these new batteries within the next five years, [all solid-state batteries] would be competing with the incumbent lithium-ion batteries for space on the roads by the early 2030s and, thus, launch the next phase of electric mobility," IEA said.

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