Jyväskylä preliminary results
The Pihko group at Jyväskylä University (JYU) focuses on the chemical synthesis of new materials that could be utilized to store energy in flow batteries. We start from natural products, such as vitamins, that possess the requisite properties as starting materials for the synthesis. After several chemical steps and purifications, we then arrive at chemically modified molecules that will then be tested whether they are going to be stable in the chemical reactions that take place in the battery. We have recently identified a key molecule that appears to possess the necessary qualities and are now exploring improved routes for the chemical synthesis as well as simpler versions of the molecule.
As shown in the figure, the newly synthesized materials are solids and readily dissolve in water. Work is underway to improve their purification and scaling up the synthesis.
So far, the JYU team has made an interesting breakthrough in the chemical synthesis of bioinspired molecules for redox flow batteries, within the CompBat project. We have now identified a pyridoxal-based molecule that appears to be stable over 50 redox cycles in aqueous media, but at present only at high pH. The key to this success lies in protecting one of the anionic groups in the molecule – without this protection, the molecules were unstable irrespective of pH. We are currently expanding on this finding with newly designed molecules that retain the protective group but include groups that should be stable in lower pH. The current hypotheses behind the stability issues will be put to test with these new materials.
A relatively robust synthetic route to these water-soluble flow battery materials has been developed, and JYU is currently also engaged in scaling up the production from milligram to gram scale. Several bottlenecks and setbacks in the synthesis have been identified and the problems have been circumvented. We have also provided materials for the electrochemical testing of the synthesized materials, in collaboration with the University of Turku (UTU) team. These experiments have provided important and decisive feedback and they will now guide our synthetic efforts as they have provided key data on the stability of the materials under different conditions. Furthermore, leveraging upon the abovementioned work, additions to the sets of molecules identified in the first CompBat WP was possible expanding it including new molecules based on the current hypotheses for stability.