Promising New Hybrid Electrolyte Presented
New publication shows successful material design for safe and sustainable lithium-metal batteries of the future
01 October 2024 – In their new study, researchers from Helmholtz Institute Münster (HI MS; IMD-4) at Forschungszentrum Jülich present aluminium oxide polycaprolactone as a dry hybrid electrolyte with improved material properties for use in lithium metal batteries (LMB). The electrolyte team led by PD Dr Gunther Brunklaus takes advantage of the fact that LMB with high-voltage cathodes are predestined for the realisation of high-energy storage systems, while solid polymer electrolytes offer an opportunity to increase battery safety and service life.
Improved Safety and Sustainability
Solid polymer electrolytes such as Aluminium oxide polycaprolactone offer a high level of operational safety as they are free from liquid and flammable components and are mechanically dimensionally stable. The simple synthesis, the possibility of upscaling and the solvent-free polymerisation also make the aluminium oxide polycaprolactone hybrid material a potentially more sustainable and cost-effective alternative to conventional electrolytes based purely on polymers.
Synergetic Effects Through Chemical Grafting
The promising electrolyte material aluminium oxide polycaprolactone is produced in a one-pot synthesis of ε-caprolactone and aluminium oxide nanoparticles as a random mixture consisting of linear polycaprolactone (PCL) and PCL-grafted aluminium oxide.
The chemical combination achieves synergistic effects in terms of mechanical stability and ionic conductivity, enabling the production of PCL-based membranes with thicknesses of 50 μm. Aluminium oxide polycaprolactone results in a remarkable ionic conductivity and rate capability for dry polymers.
"The grafting approach describes how the polymer chains are covalently. i.e. chemically, bonded to aluminium oxide particles. It has so far been underrepresented in the research field of hybrid electrolytes," explains Felix Scharf from Helmholtz Institute Münster, who is writing his doctoral thesis on this topic.
FestBatt Cooperation Project
Dr Diddo Diddens, also from Helmholtz Institute Münster, and Prof. Dr Arnulf Latz from the German Aerospace Center (DLR) and Helmholtz Institute Ulm (HIU) accompanied the study with molecular modelling of charge transport processes. This made it possible to gain a deeper understanding of how the experimentally observed increase in ionic conductivity results from grafting.
The investigations are embedded in the FestBatt competence cluster, which is funded by the Federal Ministry of Education and Research (BMBF).
Study Published in Journal Small
The researchers Felix Scharf, Annalena Krude, Peter Lennartz, Dr Annika Buchheit, Dr Fabian Kempe, Dr Diddo Diddens, Pascal Glomb, Melanie M. Mitchell, Prof. Dr Andreas Heuer, PD Dr Gunther Brunklaus, Helmholtz Institute Münster (HI MS; IMD-4) of Forschungszentrum Jülich, Moritz Clausnitzer, Dr Timo Danner, Prof. Dr Arnulf Latz, German Aerospace Center (DLR) and Helmholtz Institute Ulm (HIU), Gourav Shukla, Institute of Physical Chemistry, University of Münster, and Prof. Dr Arnulf Latz, German Aerospace Center (DLR) and Helmholtz Institute Ulm (HIU), Gourav Shukla, Institute of Physical Chemistry at the University of Münster, and Prof. Dr Martin Winter, Helmholtz Institute Münster and MEET Battery Research Centre at the University of Münster published their detailed results as an open access article in the journal "Small".
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