Sweden’s Cellfion developing PFAS-free membranes for energy storage

Swedish startup Cellfion is developing PFAS-free membranes for its LDES non-vanadium flow batteries, CEO and co-founder Liam Hardey has told ESS News.

“Additionally, we are developing PFAS-free membranes for the hydrogen industry, including applications in fuel cells, fuel cell humidifiers, and electrolyzers,” said the chief executive. “Beyond energy storage and hydrogen, our membranes also target ion-separation technologies, expanding their potential use across multiple industries.”

Cellfion was spun out of research groups at Swedish universities KTH Royal Institute of Technology and Linköping University. The company’s solution is cellulose-based and derived from wood, a naturally abundant polymer free from PFAS “forever chemicals.”

The startup uses clean fabrication and can adapt the membrane’s ion conductivity, swelling ratios, and mechanical integrity to fit diverse applications. Cellfion has been working on the technology since 2018, and spun out in 2021.

Partnerships

The company is working with partners to advance sustainable materials and, in 2022 began a collaboration with Swedish organic flow battery specialist Rivus Batteries.

The goal, CEO Hardey explained, was to create a “large-scale energy storage system using non-PFAS membranes and metal-free electrolyte materials.” He added, “The project leverages both Cellfion’s and Rivus’ core technologies to create an alternative to traditional flow batteries. We’ve made significant progress and will be sharing further updates in the near future.”

The partners say their cellulose-based membranes match the performance of commercial, fossil-based membranes.

“Beyond this, we are engaged in other R&D collaborations related to energy storage applications, some of them being supercapacitors and flow batteries based on other chemistries, together with researchers at universities in Sweden and Europe,” said Hardey.

Over the past year, Cellfion has been working with Sweden’s Umeå University on an industrial electrolysis testbed for advanced membrane development, and with Lund University, also in Sweden, on validating electrodialysis membranes within industry-relevant systems.

“We are also active in various projects focusing on filtration and ion-separation technologies,” said Hardey.

Funding

In 2024, Cellfion was awarded a €2.5 million ($2.7 million) grant from the European Commission’s European Innovation Council (EIC), and it also secured SEK 30 million ($2.96 million), alongside further funding from the Swedish Energy Agency.

That funding enabled Cellfion to move to an 800 m² plant where it is demonstrating its technology for future upscaling. The company is machine testing with suppliers and working on commercially validating its products.

“Our future demonstrator line is a key step toward scaling up production and delivering on customer-driven projects,” said Hardey. “It gives the company the capacity to refine our manufacturing processes, validate product performance, and work closely with industry partners as is now being demanded by customers.”

At the beginning of February, Cellfion announced it was taking part in a European Union-funded project to advance PFAS-free materials for fuel cells and electrolyzers. That project, Promisers, has been awarded €3 million in EU funding.

“As part of the consortium, we will contribute our expertise in ion-selective membranes and ionomers,” said the Cellfion CEO.

PFAS: the broader context

Making sustainable materials for the clean energy industry is an ongoing challenge but full PFAS phase-out may be required in future.

As recently as 2024, an article published in Nature found lithium-ion battery components are a major factor in the release of PFAS into the environment.