Development and manufacturing of forest-based membranes for electrochemical energy devices

Project Information

CNF Membrane

Grant agreement ID: 101161627

DOI

10.3030/101161627

Project closed

EC signature date 26 May 2024

Start date 1 June 2024

End date 31 May 2026

Funded under

• The European Innovation Council (EIC)

Total cost

€ 3 478 832,50

EU contribution

€ 2 435 182,00

Coordinated by

CELLFION AB
Sweden

Periodic Reporting for period 1 - CNF Membrane (Development and manufacturing of forest-based membranes for electrochemical energy devices)

Reporting period: 2024-06-01 to 2025-05-31

Summary of the context and overall objectives of the project

Cellfion’s membrane development project focused on optimizing both the membrane material and its production process to ensure high performance, scalability, and market readiness. In Work Package 1 (WP1), the company improved its membrane technology by reducing solvent use by 48%, increasing fiber charge for better ionic conductivity, and enhancing membrane stability through novel chemical and physical crosslinking techniques—all while simplifying production for scalability. Integration with membrane electrode assemblies (MEAs) was achieved through spray-coating and system-level validation. In Work Package 2 (WP2), efforts shifted to validation and quality assurance. Production was scaled via pressurized and evaporation-based dewatering methods, reinforced membrane designs were introduced, and CNF liberation processes were refined for consistency and higher yields. Functional testing showed strong performance in flow batteries and fuel cells, while collaborations with early adopters confirmed the membrane’s suitability for real-world applications, emphasizing its PFAS-free, sustainable, and cost-efficient advantages.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During the project, significant advancements were made in both membrane optimization and validation. In WP1, Cellfion streamlined the chemical functionalization of cellulose to reduce solvent use by approximately 48% while increasing the degree of modification and maintaining high yields. The process was improved by optimizing mixing and heating in new reactor vessels and replacing solvent-based washing with deionized water. The team successfully achieved a fiber charge above 600 µmol/g, enhancing ionic conductivity. In parallel, various chemical and physical crosslinking strategies were developed to improve membrane wet stability and compatibility with MEA integration. Novel crosslinkers and simplified processing routes were explored, many of which are patent pending. Cellfion also demonstrated successful MEA integration by spray-coating CNF membranes and assembling them into functional cells.

In WP2, the focus was on validating the technology and ensuring readiness for scale-up and market use. Two dewatering methods—pressurized and evaporation-based—were optimized to support large-scale membrane production, including semi-automated roll-to-roll processing. A reinforced membrane design was introduced, enabling thinner active layers while maintaining mechanical strength. CNF liberation processes were refined to ensure high nano-yield and consistent quality, with new equipment installed to improve process control. Quality assurance tests confirmed the membrane’s suitability for applications such as flow batteries and fuel cells, where it showed higher retention and performance compared to commercial alternatives. Validation with industrial partners demonstrated strong results across multiple performance metrics, highlighting the membrane’s scalability, sustainability (PFAS-/fluorine-free), and competitive advantage in the market.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The optimization of Cellfion's membrane technology has achieved promising results, surpassing existing benchmarks for state-of-the-art membranes.
1. Chemical Functionalization: The reduction of solvent use by 48%, combined with enhanced fiber charge and modification methods, has resulted in membranes with superior ionic conductivity and performance. Achieving a fiber charge above 600 µmol/g across all functionalizations positions Cellfion’s membranes ahead of current industry standards.
2. Post-treatment and Electrode Integration: Innovative crosslinking techniques, some under patent consideration, have dramatically improved the wet stability and mechanical properties of cellulose-based membranes. Additionally, successful integration with commercial CCMs has been achieved, showing the system’s potential for high-performance fuel cells.
3. Scalable Production Methods: The development of efficient dewatering techniques, including a pressurized system and optimized roll-to-roll processes, has enabled large-area membrane production while reducing drying times and material usage. The reinforced membrane design ensures robustness while cutting material costs.
4. Product Quality Assurance and Market Validation: External validation confirms the superior performance of Cellfion’s membranes in flow batteries and fuel cells. The membranes show exceptional cycling stability, outlasting commercial alternatives, and demonstrating clear advantages in vapor transport, mechanical strength, and scalability. This has garnered interest from European manufacturers, accelerating commercialization.

Cellfion Membrane