Metal-air batteries use oxygen from the air to produce electricity. The advantage here is that, unlike a conventional alkaline battery or Li-ion battery, the oxygen does not need to be stored inside the battery. The theoretical specific energy of these batteries is significantly (3-30 times) larger than the current state of the art Li-ion batteries. These batteries are also intrinsic safe since they will not start a fire or explode during operation due to the use of friendlier aqueous electrolytes.
Metal-air batteries are classified according to the type of metal used in the negative electrode, where the most common is Zn, Mg, Al, Si, and Fe. As these batteries mostly use earth abundant materials like Zn, Al, Mg, Si, C, Mn, etc., they would be significantly cheaper in the market if the challenges regarding improving the practical specific energy, specific power and cycle life. Although metal-air batteries are known for more than 100 years, their penetration into the wider market is impeded mainly by the performance and stability of the electrodes, electrolyte, and cell design.
SINTEF has a wide range of competence within different metal-air battery technologies (rechargeable Zn-air (https://gemini.no/2018/05/vil-lage-superbatteri-i-containerstorrelse/) and primary Mg-air (https://www.tu.no/artikler/bygger-batteri-av-magnesium-sjovann-og-karbon/486771)) ranging from catalysts and electrodes development to multi-scale modeling to life cycle assessment. Currently, SINTEF is focusing on the following topics:
- Development of porous zinc anodes with high utilization and structural stability
- At SINTEF we have developed a cost efficient, low temperature process of fabricating porous zinc electrodes through the cold sintering process. The manufacturing process is straight forward and up scalable, and the electrodes produced from this route is found to show good performance in a rechargeable Zn-air battery configuration. (https://doi.org/10.3390/pr8050592)
- Wide knowledge base and test equipment to study the electrochemistry of various anode materials like Al, Fe, Mg, Si, Zn, etc. and their alloys.
- Development of gas diffusion air electrodes with good cyclability and specific power
- Catalysts synthesis, physicochemical characterization, electrochemical studies
- Optimizing support and catalyst materials vs. performance and stability
- Porous bifunctional electrodes for rechargeable metal-air batteries
- Laboratory-scale testing for half-cell and full-cell validation
- Experience in the design and development of test cells with optimized performance with the aid of model simulations
- Various test equipment to test electrodes of various sizes and form factors under a variety of conditions regarding benchmarking and long term cyclability studies
- Electrolyte-electrode interaction and optimization with aqueous and non-aqueous electrolytes
- Continuum-scale simulation of aqueous metal-air batteries (https://doi.org/10.1002/cssc.201701468, https://doi.org/10.1002/aenm.201903470)
- Characterization of begin of life electrodes and postmortem physicochemical and electrochemical analysis (https://doi.org/10.1002/aenm.201903470)