To celebrate the growth and development of the RSC Applied Polymers community and to highlight the remarkable authors who continue to contribute their high quality work to the journal, we would like to share the opinions and insights of these authors through this introductory blog post. Once dubbed #RSCAppliedfirst50, our blog posts aim to give a voice to the authors behind the research and hope that their insights might shed light upon growing challenges and progress in polymer science and its applications.
In this edition, we hear from Marissa Gallmeyer, Thorfinnur A. H. Baldvinsson and RSC Applied Polymers Emerging Investigator Whitney S. Loo as they discuss their recently published article ‘Perspective: ion transport mechanisms and the significance of glass transition temperature in PEO-based polymer blend electrolytes for next-generation Li-batteries‘.
An introduction from the authors
A growing energy demand and the desire to move away from fossil fuels to renewable energy solutions necessitate advancements in energy storage technologies. While commercial electrolytes for Lithium (Li) batteries exhibit high ionic conductivities, they are highly flammable and unstable against Li metal anodes. Solid-state polymer electrolytes offer a promising, safer alternative enabling high-energy-density Li metal batteries. Polymer blend electrolytes are a promising option to improve the polymer electrolyte performance; however, fundamental understanding of the ion transport mechanism and the thermodynamics governing miscibility in ion-containing blends is limited.
Ion motion in polymer systems is typically described as either coupled with or decoupled from polymer segmental motion. However, several other factors, such as the ion solvation environment and salt dissociation behavior, can strongly influence the ionic conductivity. By calculating a reduced conductivity, the effects of segmental motion can be isolated, offering insights into the molecular origins of observed differences in ionic conductivity between systems. Furthermore, the thermodynamic interactions between components in a blend can be evaluated by fitting glass transition temperature (Tg) data to available models.
In this perspective, we find that the contributing factors to ion motion within polymer blend electrolytes is highly dependent on the salt anion. In polymer blends where lithium perchlorate is the dopant, we determined that polymer segmental motion is the main indicator of ionic conductivity. However, in blends doped with lithium bis(trifluoromethanesulfonyl)imide, it appears that the polymer architecture plays a larger role. The ionic conductivity of the single ion conducting polymer blend electrolytes is even more complex, as the amount of charge carriers is tied to the polymer blend composition. In these systems, the ion solvation environment plays a more important role in ion transport behavior than the quantity of charge carriers present.
We hope that this perspective not only provides information on the individual contributions of salt chemistry, blend architecture, and segmental motion, but that it can also serve as an informative guide to evaluating polymer electrolytes. While each individual contribution to the area of polymer electrolytes is important, it is also beneficial to conduct direct comparisons across the field to uncover fundamental insights into how polymer chemistry and blend architecture can be engineered to improve electrolyte performance.
Meet the Emerging Investigator
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Whitney Loo joined the Department of Chemical and Biological Engineering as an Assistant Professor in January 2023. Whitney obtained her B.S. in Chemical Engineering from MIT and her Ph.D. in Chemical Engineering from UC Berkeley with Nitash Balsara studying block copolymer electrolytes for Lithium metal batteries. She completed her postdoctoral training jointly at the University of Chicago with Paul Nealey and the Molecular Foundry at Lawrence Berkeley National Lab with Ricardo Ruiz. Her postdoctoral research involves the design of novel polymers and nanofabrication techniques for block copolymer nanolithography. Her independent research group at UW-Madison focuses on designing polymers for a more sustainable future and her group conducts polymer physics research in energy storage, advanced manufacturing and plastics recycling. To recognize her research achievements, she was recently awarded the DOE Early Career Research Award and the Vilas Early Career Investigator Award. |
Meet the authors
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Marissa completed her Bachelor’s and Master’s degrees in Chemical Engineering from Michigan Technological University. She then joined the Department Chemical and Biological Engineering at University of Wisconsin-Madison to pursue a PhD under the guidance of Dr Whitney Loo. Her research interests include the structure, dynamics, and ion transport in blend electrolytes. |
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Þorfinnur received his Bachelor’s degree in Chemical Engineering from the University of Iceland. He then started his PhD studies at the University of Wisconsin-Madison under the mentorship of Whitney Loo. His research focuses on the ion transport and electrochemical characterization of single-ion conducting polymer blend electrolytes. |
Perspective: ion transport mechanisms and the significance of glass transition temperature in PEO-based polymer blend electrolytes for next-generation Li-batteries
Marissa Gallmeyer, Thorfinnur A. H. Baldvinsson and Whitney S. Loo
RSC Appl. Polym. (2026) 4 (4): 1160–1178. https://doi.org/10.1039/d6lp00078a
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