London’s Cocoon Carbon Raises €13M Funding In Series A Round

The round was co-led by 2150 and Brick & Mortar Ventures, with participation from TVC (The Venture Collective) and continued backing from existing investors Wireframe Ventures, Celsius Industries, Gigascale Capital, and SOSV.

Cocoon Carbon’s Series A comes at a time of increasing investment in low-carbon construction materials and cement decarbonisation technologies across Europe. By focusing on scaling supplementary cementitious materials (SCMs) derived from steel slag, the company targets the materials supply layer, complementing other approaches such as carbon capture, mineralisation and digital optimisation.

Founded in 2023 by Eliot Brooks, Will Knapp and Freddie Scott, Cocoon Carbon is developing a scalable, cost-competitive cement replacement to help producers meet rising infrastructure demand without increasing costs.

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With data center construction booming and global infrastructure expected to double over the next 40 years, the supply of widely-used low-cost supplementary cementitious materials (SCMs) has become critical. Cocoon converts electric arc furnace (EAF) steel byproducts into high-performance SCMs, offering a low-capex modular process that lowers the carbon intensity of concrete production.

Historically, SCMs have been sourced from heavily polluting coal plants and iron blast furnaces, but as these industrial processes are retired across the U.S. and Europe, supply is shrinking while incumbents consolidate. At the same time, demand for SCMs is growing at 6–7% per year, with prices in some markets doubling since 2017.

Cocoon taps into the underutilised supply of steel slag from EAF steelmaking where scrap is re-melted using electricity rather than coal to create a reliable, low-cost cement replacement. With tens of millions of tons of slag produced annually and EAF steelmaking projected to double by 2050, Cocoon expands the domestic supply base for concrete producers, helping stabilise costs.

“The SCM market is facing a structural deficit at exactly the moment infrastructure demand is rising,” said Eliot Brooks, CEO and Co-Founder of Cocoon Carbon. “We’re focused on delivering a plug-and-play solution that gives concrete producers access to affordable, local materials – while improving the economics of electric steelmaking. Expanding supply is the fastest way to stabilize costs and lower carbon in concrete.”

The company’s SCM reportedly matches the performance of traditional materials while reducing concrete’s embodied CO2 by up to 40%. Unlike many emerging alternatives Cocoon’s product is cost-competitive and does not require a prohibitive “green premium,” making adoption more feasible for the market.

Cocoon’s technology retrofits directly into existing EAF slag handling systems, rapidly cooling molten slag 100x faster than conventional methods. This plug-and-play approach avoids high energy inputs, capital expenditure, operational disruption and safety risks. Co-located at steel mills, it also minimises transportation costs, a major component of SCM pricing, without requiring new logistics infrastructure.

The Series A round will support the deployment of Cocoon’s first commercial demonstration facility in the U.S. validating performance at industrial scale and establishing the track record for a broader rollout across more than 50 steel plants in the U.S. and Europe.

The company has already piloted its technology at a major steel mill and completed third-party validation of its material in concrete applications. Over the past year, Cocoon has expanded its R&D and concrete testing facilities in London.

To support the demo facility and scaling plans, Cocoon is doubling its team, hiring process engineers, materials scientists and commercial staff in the UK, along with plant operators and technical personnel in the U.S.

“Concrete is one of the biggest value streams on the planet, providing the foundation of our civilisation, from buildings to infrastructure to data centers. It consumes orders of magnitude more energy than AI and emits more CO2 than any other sector,” says Jacob Bro, partner and co-founder of 2150. “Cocoon stands out in the innovation landscape with a product that is better and cheaper than cement and delivers a true drop-in replacement product for the industry.”