Zusammensetzung einer Na-Ionen-Batterie Peußisch Weiß, Flüssigelektolyt. Foto: Fraunhofer IKTS
The necessary moment for sustainable battery technologies to ramp up was yesterday. Cars with sodium batteries are already on the market in China. Germany itself is only a blink of an eye away from introduction – if the right course is set now. The crucial aspect here is the clever use of regionally and technologically diversified know-how. The “New Via Regia of Batteries” offers opportunities.
A guest article by Fanny Pohontsch with Prof. Dr. Michael Stelter and Prof. Dr. Martin Oschatz in the current eMove360° magazine.
There are two aspects that are driving German industry in times of transformation: a neutral CO2 footprint with significantly reduced costs for new products. To achieve this, it is essential to rethink trade relationships, production processes, technologies and use of resources. According to a study by McKinsey, the pursuit of climate goals and the automotive industry’s move away from combustion engines will allow the global battery market to grow by 30% annually to 4,700 GWh by 2030 – today it is 700 GWh. A battery is never just a means to an end. It itself harbors previously untapped sustainability potential. The key is on our doorstep: sodium.
Sodium-ion batteries offer an opportunity for value creation in Germany
»Thanks to its unique properties, a sodium-ion battery can be used to press the reset button on the traditional way of thinking and using batteries. With sodium batteries, we can suddenly use a domestic raw material base that is independent of strategic, even critical, imports. The required technological infrastructure is also available. This is the opportunity for value creation in Germany!” says Prof. Michael Stelter from Fraunhofer IKTS and director at the Center for Energy and Environmental Chemistry CEEC at the Friedrich Schiller University (FSU) in Jena. »After more than ten years of sodium battery research, I am absolutely convinced of this!«
Germany has created important beacons of battery technology in recent years. »If we look at Thuringia and Saxony alone: These countries have done enormous preparatory work and investments, e.g. B. in the battery innovation and technology center BITC. All individual value creation steps for the development and production of batteries are already shown from western Thuringia to eastern Saxony along the A4 motorway. Like a string of pearls, thousands of person-years of experience are gathered here.«
In the Middle Ages, the Via Regia ran along today’s A4 motorway – a road that was central to the technological and economic development of the region. “Today we can talk about a new Via Regia of batteries,” says Michael Stelter. »This potential only needs to be strategically coordinated between industry and research in order to achieve the large-scale commercialization of sodium-ion batteries as quickly as possible. Smart minds, excellent material development and cell research, manufacturing companies and production, mechanical engineering and, above all, the raw materials – everything has been there for a long time and in full.
According to data from the Saxony Economic Development Agency and the Thuringia State Development Agency, over 200 players in battery research and industry are located on this axis. Current projects such as the Batterie Mitteldeutschland educational association and BeaT, both of which are funded by the BMWK, are already ensuring further recruitment and qualification of skilled workers.
Regional raw materials and upcycling of biogenic waste: Composition of sodium-ion batteries
With regard to the materials, sodium is actually unlimited in Germany and therefore available inexpensively, e.g. B. in the form of sodium chloride, i.e. table salt. The operating principles in a sodium-ion battery are similar to those in a lithium battery – both concepts are based on alkali metal ions as charge carriers. Experts know this chemistry well. You also draw on experience from related technologies, such as the ZEBRA battery from the 90s.
»Cell chemistry is crucial for relevant power density. We understand how electrode processes differ between lithium and sodium,” says Martin Oschatz, chemist and holder of the Chair of Chemistry of Materials for Energy Applications in Jena. »Hard carbons have a special affinity for sodium and high plateau capacities on the anode side. Thanks to their internal porosity, we increase the surface area and generate maximum storage volumes for sodium ions. This means that a battery achieves a high energy density. It starts at the nanometer level.«
Hard carbons are amorphous carbons. They replace graphite and are produced by simply heating suitable raw materials – in particular from carbon-containing biogenic waste, such as nut shells or brewer’s spent grains. Of this, 1.5 million tons were produced in Germany in 2019 alone. On the cathode side, researchers use Prussian white, among other things. This is a dye that has been known as Prussian blue for 100 years and consists of equally readily available elements such as iron, carbon and nitrogen.
So what about the recycling of sodium-ion batteries if the raw materials used are inherently environmentally friendly, non-critical and cheap? According to Michael Stelter, recycling sodium-ion batteries is much easier than lithium batteries because the cells do not contain copper and cobalt. »Recycling is therefore only required for the few valuable metallic elements of the battery. In addition to iron, this is particularly about aluminum, which we use as a current conductor. However, the upstream syntheses of battery materials with the potential to directly recover the materials produced would certainly be interesting for the ecological footprint in recycling.
Use of sodium-ion batteries in inexpensive electric cars and private households
With the sodium-ion battery, experts are initially addressing mobility, followed by private households and industry. »Electric micro, small and medium-sized vehicles – simple, inexpensive cars that don’t have to travel 800 km for their purpose: This is a huge market that cannot be served with sophisticated, expensive lithium technology and that in terms of “The mobility transition is much more valuable,” says Stelter.
According to ADAC e.V., the average basic list price for an electric vehicle in the small car segment is currently €36,400. By using sodium-ion batteries, production costs can be reduced so that affordable electric cars could also roll off the assembly line in Germany in the future. “It usually develops in parallel: Anyone who produces such batteries can basically offer them cheaply for private households with 10 kWp solar systems on the roof or use them as industrial electricity storage devices,” adds Martin Oschatz. The price development for the critical components in lithium-ion batteries in the next few years will be decisive for the cost advantage of sodium technology.
However, he considers the idea of being able to catch up with China to be illusory: “That is no longer possible in the short term and based on the established technologies. Almost 90% of the patents related to sodium technology come from China. What we are experiencing now is a wake-up call; that we must take the helm again with creative technological ideas and solutions and take action!” The two researchers emphasize the urgent need for regionally and technologically diversified promotion of environmentally friendly battery technologies: “By using the different potential and strengths of different players in the industry , together we can accelerate development and technology transfer. With a concentrated cluster approach that encompasses the entire technology chain, industrial mass production of sodium-ion batteries could be achieved in Germany within five years. The New Via Regia of batteries can be a springboard here. A double-digit million sum is needed for the rapid technology transfer.
Conclusion:
Germany has all the prerequisites for the success of sodium-ion batteries. Now further political funding and cooperation between industry and research will decide how quickly the batteries come onto the market here. Either way, says Martin Oschatz, he and Michael Stelter are pulling out all the stops to advance this technology. “Because if there’s one thing we’re convinced of, it’s sodium ion technology.”
