The material is processed in moderately warm water rather than using an energy-intensive process involving harmful solvents (as with standard fluorinated material). As Klaus Bretterbauer and Felix Leibetseder explain in the scientific journal “Advanced Energy Materials”, batteries can be more durable as the material adheres better to the current collector.

During an interview with APA, Bretterbauer and Leibetseder (JKU Institute for Chemical Technology of Organic Materials) explained that the cathode binder’s basic building block is a substance derived from castor oil, a natural product obtained from the seeds of the miracle tree (Ricinus communis). Known as “11-aminoundecanoic acid”, the compound is linked to form long chains (polymers). Felix Leibetseder remarked: “The binder acts as an adhesive, adhering the materials to the current collector and preventing everything from literally falling apart while the battery is charging and discharging.” Klaus Bretterbauer added: “The new binder adheres to the aluminum foils used as current collectors in these types of batteries about ten times better than conventional 'polyvinylidene fluoride', thereby significantly reducing the likelihood of battery failure resulting from the electrode detaching itself from the collector.”

In addition, commonly used PVDF materials and their processing agents (classified as perfluorinated and polyfluorinated alkyl compounds, or PFAS for short) are being banned in the EU on account of numerous known health hazards. To use PVDF for electron production, a solvent called “N-methyl-2-pyrrolidone” (NMP) is used, a compound that is known to impair fertility. Bretterbauer stated: “Our binder is fluorine-free and water-soluble, which means that during production, we can use water instead of NMP.” As a result, there is no health risk to the production personnel and no toxic waste. As a solvent, water can be removed at lower temperatures than NMP, meaning that the electrode manufacturing process requires less energy.

The material is not only water-soluble, it can easily be salvaged when the product is at its EoL (end of life) stage. Bretterbauer added: “The rare critical raw battery materials - such as lithium, manganese and cobalt - are also easier to recover. Batteries containing PFAS, on the other hand, are not only toxic and difficult to recycle, they are also a serious environmental hazard.”

Environmentally-friendly alternatives
The JKU researcher stated: “Overall, our approach is much more environmentally friendly.” Some time ago, a substitute for materials deemed hazardous to human health was discovered on the other side of the battery, on the anode. He added: “We have now also been able to develop a harmless material for the positive side that is not only made from renewable raw materials, it does not compete with food production, and it adheres better than what we are currently using.”

When it comes to using the new binder, the researchers believe the sky’s the limit. What began as base-knowledge research at the JKU to developing a prototype right here on campus could potentially be used to hold battery components together in everything from cell phones to electric cars. Leibetseder added that together with Karl-Heinz Pettinger (Landshut University of Applied Sciences in Germany), they are currently using the new material to test button cells as well as larger battery prototypes produced by a “room-filling machine”. He added that these have proven to be so successful that talks are now underway with industrial partners. Bretterbauer commented: “We hope that we can soon test our prototypes with them and see how they behave in demanding conditions, such as in the automotive sector, for example.” He is confident and optimistic that, “… we can expect to see these new batteries in the very near future”.

(APA)