A promising alternative to lithium-based batteries

Researchers at the Faculty of Science and Technology of the University of Debrecen have developed a prototype of an environment-friendly, high-performance, rechargeable zinc-air battery. This new type of energy store is based on cellulose and uses biodegradable materials as additives and membranes. Its development is in the scale-up phase.

The usability and storage possibilities of renewable energy have been examined for a long time by researchers of the Department of Applied Chemistry of the Faculty of Science and Technology (TTK) of UD.

- There are various types of accumulators, but their energy storage capacities are limited, which generally hinders a broader use of renewable energies. Concerning today’s lithium batteries, several barriers prevent their further development, such as their limited capacity and cumbersome reusability. The latter also means that they can hardly be integrated into the circular economy, and long-term economic and environment protection goals are also limited as a result. Some research is being done on the possible solutions to these difficulties of lithium-based systems and on the replacement of lithium with another metal. In our development, we apply zinc anode. More exactly, zinc-air batteries are a subcategory, as zinc is our anode and oxygen is obtained from air during the cathode process – explained the fundamentals of the research Tibor Nagy, associate professor of the Department of Applied Chemistry of the Chemistry Institute of UD TTK.
The specialist claims that another advantage of this system is that it has a high theoretic capacity, and due to this, it is a promising alternative to lithium-based batteries.

- In contrast to other studies, we did not examine a half-cell only but set up a complete zinc-air system that can function as a battery alone. This is how we created our prototype that can be used for storing electric energy. What makes this system unique is that it simply consists of a zinc anode and activated carbon cathode, which are very cheap. Another advantage is that there is no catalyst, so the prototype is free of heavy metals. The energy storage is realized with the help of oxygen obtained from the air on the cathode-side – Tibor Nagy added.

The prototype operates in a lower working voltage range compared to conventional zinc-air systems, which allows the battery to work in much gentler conditions. As a result, the operation is stabler and the detrimental processes reducing capacity and lifespan are reduced.

- There is zinc on the anode and the activated carbon is not a catalyst, so there is not any catalyst at all. This is also good because it is simple and environment-friendly. As an electrolyte, alkali is used that can be neutralized relatively easily. We only use one additive, the so-called carboxymethyl-cellulose, which is a cellulose-based polymer. So, the wool jacket separating the two electrodes and allowing us to do electrical work with the battery is also natural and environment-friendly. To sum it up, our system can easily be produced, is simple, cost-efficient, easily reusable, and free of problematic elements – the researcher said.

He explained that using the appropriate geometry was an important part of the development process. After designing the cells, they used 3D-printing for this, which made it possible to test the geometry efficiently and to form the cell body precisely.
In addition to the staff of the Department of Applied Chemistry of UD TTK, the specialists of the Department of Solid State Physics also joined the research.

- Our prototype is ready, so now, in the scale-up phase, our aim is to increase its performance without losing the positive features. We are primarily working on increasing the capacity, but we have also connected the cells to have greater output voltage. We receive a contribution to it from the University’s Proof of Concept application which allows us to design a system with a considerably higher capacity – Tibor Nagy detailed the plans.

The researchers of Debrecen University published the details and results of their research in the Journal of Energy Storage. For the paper, Tibor Nagy was awarded the Publication Prize of the Count István Tisza Foundation for the University of Debrecen.

Press Centre - TH