Innovative approach by developing oxygen blocking membrane electrolytes for novel solid state sodium-air batteries

Project Information

OXBLOLYTE

Grant agreement ID: 101067009

DOI

10.3030/101067009

Project closed

EC signature date 1 July 2022

Start date 17 April 2023

End date 16 April 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 181 152,96

Coordinated by

CENTRO DE INVESTIGACION COOPERATIVA DE ENERGIAS ALTERNATIVAS FUNDACION, CIC ENERGIGUNE FUNDAZIOA
Spain

Periodic Reporting for period 1 - OXBLOLYTE (Innovative approach by developing oxygen blocking membrane electrolytes for novel solid state sodium-air batteries)

Reporting period: 2023-04-17 to 2025-04-16

Summary of the context and overall objectives of the project

The OXBLOLYTE project addressed critical challenges in sodium-based batteries (NaBs) by developing innovative polymeric membranes based on microporous Polymers of Intrinsic Microporosity (PIMs), in combination with ionic liquids (ILs). The primary objective was to engineer a novel quasi-solid polymer electrolyte (QSPE), either in the form of PIM/IL or PIM/liquid electrolyte (LE) systems, capable of delivering high ionic conductivity, suppressing oxygen crossover, and enhancing battery stability.

The project successfully met its main goals. High-purity (>99%) PIM membranes with tailored pore sizes ranging from 2 to 10 nm were synthesized and integrated with ionic liquids to fabricate QSPEs. These electrolytes demonstrated excellent electrochemical performance, with ionic conductivities in the range of 10⁻³ to 10⁻⁴ S cm⁻¹, a favorable sodium-ion transference number (tNₐ⁺), and outstanding stability. When tested in Na–O2 batteries, the QSPEs enabled stable cycling for 40–50 cycles, delivering capacities of 2–3 mAh cm⁻² at a current density of 75 µA cm⁻². These promising results confirm the effectiveness of combining PIMs with ILs, offering improved oxygen solubility, minimized oxygen crossover, and enhanced control over discharge products. Importantly, the developed QSPE materials demonstrate strong potential not only for Na–O2 batteries but also for next-generation Na-ion battery technologies, thereby contributing to the advancement of sustainable and high-performance energy storage solutions.

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

In the OXBLOLYTE project, we successfully developed a novel quasi-solid polymer electrolyte (QSPE) based on microporous PIM membranes combined with ionic liquids for application in Na–O2 batteries. High-purity (>99%) PIM membranes with pore sizes below 2 nm were synthesized. In parallel, Pebax-based biopolymers were also explored, opening a new research avenue for Na–O2 battery systems. Through systematic experimental work, advanced material characterization, and electrochemical testing, the performance of the newly developed QSPE was thoroughly validated. The electrolyte exhibited ionic conductivities in the range of 10⁻³–10⁻⁴ S cm⁻¹, which is suitable for solid-state Na–O2 battery operation. Electrochemical tests demonstrated stable cycling over 40 cycles, delivering a specific capacity of 2–3 mAh cm⁻² at a current density of 75 µA cm⁻². Additionally, we developed and validated cell architectures with effective oxygen crossover suppression.

The combined results highlight the strong potential of both PIM-based and Pebax-based electrolytes for next-generation Na–O2 and Na-ion battery technologies. High-impact scientific outputs have already been achieved. For instance, a review article on Na–O2 battery perspectives has been published in Advanced Energy Materials, and a research manuscript on the Pebax-based QSPE has been submitted to Advanced Science. Two additional manuscripts are currently under preparation. Moreover, the project outcomes have been disseminated at major international conferences, including EUROMEMBRANE 2024 (Czech Republic), GEP 2024 (Spain), and the 76th Annual Meeting of the International Society of Electrochemistry (Germany).

List of Publications:
o Mohamed Yahia, Idoia Ruiz de Larramendi, Nagore Ortiz-Vitoriano, Harnessing the Potential of (Quasi) Solid-State Na-Air/O2 Batteries: Strategies and Future Directions for Next-Generation Energy Storage Solutions, Advanced Energy Materials, IF (27.8) https://doi.org/10.1002/aenm.202401398
o Mohamed Yahia, Marina Enterría, Cristina Pozo-Gonzalo, Nagore Ortiz-Vitoriano, A new Quasi-solid Polymer Electrolyte for Next-Generation Na-O2 Batteries: Unveiling the potential of PEBAX copolymer System, Advanced Science, IF (15), submitted 2025.
o Mohamed Yahia, Marina Enterría, Cristina Pozo-Gonzalo, Nagore Ortiz-Vitoriano, A new Quasi-solid Polymer Electrolyte for Next-Generation Na-O2 Batteries: Unveiling the potential of PIM/IL composite system, Ongoing (preparation/submission 2025).
o Mohamed Yahia, Nagore Ortiz-Vitoriano, Perspective: Polymers of Intrinsic Microporosity (PIMs) for Battery Applications: Opportunities, Challenges, and Future Directions, ongoing (preparation/submission 2025).

List of Conferences and Meeting:
o Euromembrane 2024, 8-12 September 2024, Prague (Czech Republic), Oral presentation, website (https://euromembrane2024.cz/).
o XVII Meeting of the GEP Polymer Specialized Group (GEP 2024), 16-19 September 2024, Madrid (Spain) Oral presentation, website (https://gep2024.com/GEP2024).
o Block Course 2024: "Materials, Functioning and Technology of Batteries" of the GS-EES: Graduate School Electrochemical Energy Storage, April 2024, Ulm University (Germany).
o 76th Annual Meeting of the International Society of Electrochemistry, 7-12 September 2025, Mainz (Germany), website (https://www.ise-online.org/meetings/76th-annual-meeting-of-ise-2/#gsc.tab=0).

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 OXBOLYTE project has demonstrated significant progress in developing quasi-solid polymer electrolytes (QSPEs) based on polymer of intrinsic microporosity (PIMs) and ionic liquids (ILs) for Na-O2 batteries, moving beyond the current limitations of liquid-electrolyte systems. These innovative materials offer improved electrochemical stability, ion transport, and safety performance, which are critical for enabling next-generation energy storage solutions.

Key advancements include:
1. Development of novel PIM/IL hybrid membranes with superior Na⁺ conductivity and oxygen permeability.
2. Demonstrated enhanced cycling performance and reversible discharge product formation under ambient conditions.
3. Integration of environmentally benign components with potential for scalable synthesis.
These results address major bottlenecks in Na-O2 technology such as poor electrolyte stability, dendrite formation, and limited cycle life and position OXBOLYTE at the lead of solid-state metal–air battery innovation.

Needs for Further Uptake and Success
To fully realize the social and commercial impact of these findings, the following actions are identified:
1. Further research and pilot demonstration of pouch-cell scale prototypes to validate performance under practical conditions.
2. IPR supports patent filing to protect electrolyte innovations and cell architecture.
3. Access to funding and industrial partnerships to enable scale-up and manufacturing readiness.
4. Engagement with standardization bodies and regulatory stakeholders to align with emerging EU battery regulations (e.g. Battery Regulation 2023/1542).
5. Participation in international collaboration platforms for knowledge transfer and market alignment.

Overall, OXBOLYTE contributes to the EU’s strategic objectives for sustainable, safe, and high-performance energy storage, supporting the energy transition and Green Deal targets.

GEB meeting 2024

Block Course 2024

Euromembrane 2024

OXBLOLYTE Concepts

Publication