Researchers develop hybrid materials for more efficient thermal energy storage

Heating and cooling buildings accounts for a large portion of global energy use. Researchers from Texas A&M University are developing a new class of hybrid materials that could help store thermal energy more efficiently for use in buildings and other technologies.

The materials, which the research team from the Department of Materials Science and Engineering call salogels, combine inorganic salt hydrates with polymer structures. Salt hydrates can store substantial amounts of thermal energy, absorbing heat during the day and releasing it later as temperatures fall. They are also highly resistant to burning. The main problem is that, on their own, they can leak and break down with repeated use. Introducing a polymer network or structure into them can resolve many of these concerns without sacrificing storage capacity. 

“Salogels represent a shift from simply storing heat to engineering multifunctional materials that combine thermal energy storage and conversion,” said Dr. Kartik Kumar Rajagopalan, a research scientist in Texas A&M’s Soft Matter Facility (SoMF). “By understanding how polymers interact with salt hydrates at the molecular level, we can begin to design materials with properties tailored for real-world energy applications.”

Rajagopalan led the research under the direction of Dr. Svetlana A. Sukhishvili, professor and director of the SoMF. The work was featured on the cover of ACS Applied Materials & Interfaces. Dr. Peiran Wei, SoMF facility manager and senior research scientist, is credited with designing the cover art — the gummy bear-shaped salogel — for the publication’s June 10 issue. 

The work builds on several years of research by Sukhishvili’s group examining interactions between polymers and salt hydrates. One major finding was that the polymer network changed how the salt hydrates crystallize and helped prevent supercooling. The findings could inform a future machine learning tool used to design new materials with tailored properties. 

Beyond building uses, the team is exploring applications in batteries and temperature-control electronics, smart windows, anti-icing coatings, supercapacitors and energy conversion systems. 

Funding came from the National Science Foundation’s Designing Materials to Revolutionize and Engineer our Future program. Rajagopalan said the group’s next steps include improving the mechanical strength of salogels, reducing supercooling further, testing with 3D printing for processing and applying the material to electrochemical energy conversion. 

By Leon Contreras, Texas A&M University College of Engineering