Investment of the month: CarbonX is ready to play its part in Europe’s battery industry
Every month, we interview a startup that has received an investment recently. This month: CarbonX.
Published on January 8, 2025
Mauro traded Sardinia for Eindhoven and has been an editor at IO+ for 3 years. As a GREEN+ expert, he closely monitors all developments surrounding the energy transition. He enjoys going on reports and likes to tell stories using data and infographics. He is the author of several series: Green Transition Drivers, Road to 2050, and Behind the Figures.
The €4 million raised in December by CarbonX will be used to secure feedstock, increase battery testing capacity, and prepare for a facility in the port of Rotterdam. Officially founded as a spin-off of the Delft University of Technology (TU Delft) in 2014, the company has come a long way, pivoting and now making its way in a key innovation sector.
CarbonX has developed a technology to produce a material with comparable energy density to graphite, which is widely used in the critical component of batteries, the anode—the positively charged electrode. More than 95% of graphite comes from China. The Dutch startup offers an alternative to stimulate local material production, reduce external dependencies, and foster the creation of a battery value chain in Europe.
CarbonX’s story
15 years ago, Rutger van Raalten, CarbonX’s CEO, was finishing his master’s thesis in chemical process engineering at the TU Delft. It was back then that while working on an electrode for a fuel cell, the eureka moment happened. “In what I recall as an infamous Friday afternoon, over some pizza and beers, we tried to shorten the procedure to a single-step one. The electrode we were trying to develop didn’t work, but we figured out a way to manipulate the carbon structure.”
Then, the university filed a patent, and Van Raalten, together with then post-doc and co-inventor Daniela Sordi, volunteered to bring the technology forward. Throughout the years, the two explored different applications. Their powder was added to strengthen the material in a project for upcycling plastics. In another trial, the graphite equivalent proved to be successful in improving tire wear properties and range. At the same time, the team scaled the production of CarbonX to commercial volumes by using existing carbon black production facilities. However, there was no way to make these two lines of business profitable, while more possibilities – and attention – lie in the battery market.
“It was never a linear process, as we were working on different things at the same time. It took us 10 years to find our way. We pivoted from an advanced materials company to a supply chain solution, which might be less sexy, but it is certainly more needed,” says the CEO.
A more sustainable alternative to graphite
Graphite can be mined or produced synthetically. When made artificially, the material requires an energy-intensive process that can use, to name a few, petroleum coke, pitch coke, and coal pitch as usable feedstocks. These are the baked at up to 3000 °C for a few weeks, hence requiring high energy inputs.
CarbonX employs carbon black oil, a sidestream coming from oil refineries. The startup designed a carbon black process that uses five times less energy than synthetic graphite. An emulsion is created from the oil, which forms a template for a three-dimensional network structure that can store lithium ions and can conduct electricity. The result is a powder with energy densities similar to graphite, made with a process that turns out to be competitive with what is already on the market– given the lower energy inputs.
One of the key benefits of using CarbonX’s feedstock technology is that it consumes low energy compared to synthetic or natural graphite, resulting in lower costs and a reduced carbon footprint. It seamlessly integrates into existing carbon black manufacturing plants, enabling a 100-ton-per-day production capacity today. Van Raalten explains that a thousand tons of the material is enough for 1 GWh of battery capacity—enough to supply 20,000 average electric cars.
A material layer - © CarbonX
Growth in sight for CarbonX
2024 was certainly a year to remember for Van Raalten. “We received the validation we were seeking from our customers and developed our technology further. Considering the standard for battery development, I think what we achieved in these 12 months was extraordinary.”
Currently, 15 people work for CarbonX, with some working directly on battery production sites, helping customers integrate their technology into existing battery lines. “In the coming year, we will focus all of our efforts on helping the existing customers towards supply agreements and prepare for the next funding round—worth €25 million—which we expect to close in the first quarter of 2026,” adds the co-founder.
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Securing a solid materials supply chain
Further down the line, Van Raalten sees setting up production facilities in the United States and in Europe. Given the tax incentives the American Inflation Reduction Act provides, he sees the possibility of opening a factory overseas. CarbonX’s material production can be done virtually anywhere by leveraging local carbon black feedstocks.
Graphite is also on the EU’s list of 34 Critical Raw Materials (CRMs), a catalog of key materials for the energy transition. In 2024, the EU adopted the Critical Raw Materials Act, setting new sourcing, recycling, and mining standards, aiming for a diversified, affordable, and sustainable supply by 2030. “It is a good sign, yet it lacks the funding to stimulate the establishment of a solid European materials chain,” Van Raalten underlines.
“As Europe, we need to decide, in a couple of years, whether our battery industry is still relevant. I think there is still a chance to build it properly, despite the enormous delay. To this extent, the latest investment of CATL and Stellantis in a gigafactory in Spain gives me hope. However, we must speed up, unlock funding, and reach agreements with Asian cell manufacturers. We should focus on operational excellence and build gigafactories in partnership with global market leaders before it is too late,” he stresses.
In this process, the entrepreneur also highlights the importance of collaboration between all the stakeholders of the battery supply chain. Joining forces means derisking investments and strengthening ties between material, cells, and technology producers.
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CarbonX has found its balance
Var Raalten did not plan to become a CEO. His and Sordi’s main goal has always been having an impact. As CarbonX prepares to expand, he believes they are finally leaving a mark with a technology that reduces the environmental footprint connected to graphite production.
“What my cofounder and I have in common is that we believe this is possible, and in these 15 years, we have had our fair share of ups and downs. Entrepreneurship is all about resiliency. Sometimes you don’t know things, and some others you do, and it is always about finding the right balance at every stage the company goes through,” he concludes.
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