An alternative to traditional batteries
Batteries basically function by having two reactants; substances of which one wants to deliver electrons to the other. This is a spontaneous process that happens automatically if the two substances meet. The process is utilized in batteries by separating the reactants in different chambers and forcing the electrons to move from one to the other through a wire. The generated electricity can then be used for powering items such as a lamp or a mobile phone.
When the battery is dead, we charge it by applying voltage and making the reaction run the other way. Typically, the electroactive substances are not very environmentally friendly – usually we use metals that are both rare and constitute an environmental concern when we dispose of the batteries
- “So when Jens suggested that he could provide some organic, potentially electroactive substances that are easily biodegradable, and which could also be produced in an environmentally friendly way by fungi, that could potentially be used for delivering and receiving electrons in a battery, I immediately saw the huge potential in the concept, and soon after we started developing the idea into a project proposal.”
The two researchers therefore have a very clear division of work in the project, as each has his very specific area of expertise. They now work on refining their respective tasks to fit the united whole optimally: Jens Laurids Sørensen works on identifying the optimal kind of quinones and maximising the production, while Jens Muff works on optimising the utilisation of the quinones in a battery.
Targeted quinone production
While Jens Laurids Sørensen knew from the beginning that his fungi are capable of producing quinones, the process of identifying exactly which quinones are the optimal ones for battery use is a far from simple task.
- “The fungi are capable of producing thousands of different quinones, so the first step is the basic identification of which will work best in this battery setup. For this purpose, we are collaborating with a researcher in Scotland who can perform advanced computer simulations to identify which quinones have the best electro-chemical characteristics and are at the same time durable for quinone production at an industrial scale. A PhD student supervised by Jens Muff will visit the researcher in Scotland to work on this simulation process, and hopefully their results will enable us to select the 20 most promising quinones that we can then test in practice in our lab” he explains. After identifying which quinones to test, the next step is ensuring that the fungi used produce the exact quinones they want to test – a process that requires an element of what is by now fairly basic genetic engineering for the researchers.
- “In order to make the fungi produce the exact quinones that the simulation processes have identified as promising, we need to identify the gene that is responsible for the production of that quinone, and then isolate that gene and insert it into our fungus strain, for instance a type of yeast. Then we need to determine the best way to increase the production – for instance by changing the chemistry of the container or by increasing the synthesis. We need to find the optimal conditions so that the fungi produce the substance we want in a large amount, but without producing a lot of other unhelpful substances that might impede or even be toxic to the fungi themselves” Jens Laurids Sørensen explains. The aim is to end with a fungus strain that provides a stable, prolific and scalable production of the exact quinones that are best suited to the batteries.
A potential solution to a global challenge
While Jens Laurids Sørensen works to improve the quinone production, Jens Muff works on optimising the battery setup for maximum flexibility and scalability. For this purpose, he aims to use an untraditional battery technology.
One of the challenges of typical batteries is that the electroactive substances are placed inside the battery, which limits the size and weight of the amount of electroactive substances you can place inside your battery – and as such how much power you can gain from it. In the concept we work with here, we use the so-called redox-flow battery technology where the two parts of the battery are separated
In redox-flow batteries, the electroactive substances are placed in containers outside the electro-chemical reactor cell that contains electrodes, and which is the place where the actual electron transmission takes place.
- “In our setup, we place our fungal quinones in large containers next to the electro-chemical cell, which allows us to scale the size of the containers according to how large power capacity we need. The separation of the electroactive quinones from the reactor cell furthermore allows us to pump the quinones through the electro-chemical cell whenever we need to, thereby triggering the electron transmission to either release power or recharge the quinones. Thus, we have much larger control of both how much of the electroactive substance we can have present; how much we want or need to charge the battery – for instance, do we need to store energy from a huge windmill farm or from a single-house solar-power-cell system – as well as how much power we want to release at any given point in time” Jens Muff adds.
- “Being able to control these parameters provides redox-flow batteries with the potential to be used at a very large scale, but the only reason that we even dare to consider using them at the necessary scale is that the substances used are biodegradable and comparatively harmless. In theory, we can simply pour them out into the sewer system when we are done using them. If we were to use for instance Lithium batteries at the scale we are talking about, they would cause a catastrophe if they sprung a leak. What our setup provides is an energy-storage solution that is both sustainable, organically-produced, scalable and environmentally-friendly” he emphasises.
Unique collaboration leads to unique solution
As a first step in the research on the fungus-quinone-based redox-flow battery technology, the researchers supervised groups of Bachelor’s students who carried out tests of different elements of the battery setup.
- “Because of AAU’s project-based learning method, our students are very experienced in terms of laboratory work, both in theory and in practice. This means that we could test elements of our idea through our student groups. I had groups focusing on the production of quinones from fungi, and Jens Muff had groups working on the battery technology. We also created a cross-disciplinary group of skilled Bachelor’s students to test the setup at a small scale, which gave us a proof of concept that showed that it can actually work in practice. We used this proof of concept as one of the arguments in the project application that led to our recent grant from the Independent Research Fund Denmark for a four-year research project where we will be conducting research on the concept along with two PhD students” Jens Laurids Sørensen says.
The researchers have also submitted a project application to the Novo Nordisk Foundation along with a consortium of other researchers, including researchers from German and Scottish universities, as well as AAU’s own Department of Energy Technology in Aalborg.
- “While the redox-flow battery technology has been known since the 1970’s, and a research team at some of the foremost American universities proved in 2012 that quinones can be utilised in batteries, as far as we know no one has created a fungus-quinone-based redox-flow battery in the way we are proposing. Energy storage is increasingly verbalized as THE challenge we need to solve in order for it to make sense to continue working towards using only sustainable energy sources in the future. We believe this technology can solve that challenge for major wind turbine farms and photovoltaic power stations all over the world, and the fact that it is both organically produced and biodegradable makes the battery technology itself a sustainable element in the global power production and consumption system. We hope that our recent research grant will be the first of many that will let us see energy storage by quinone-based redox-flow batteries become the key to global conversion to sustainable energy sources in the future” Jens Muff finishes.