For many years, solid-state electrolytes have been investigated for their potential use in energy storage solutions, particularly in the development of solid-state batteries. These materials offer a safer option compared to the conventional liquid electrolytes—substances that facilitate ion movement within batteries that are currently in use. However, there’s a pressing need for innovative approaches to enhance the performance of existing solid polymer electrolytes so that they can meet the requirements of future materials.
“We proposed the idea of leveraging secondary structures—such as helices—to refine and enhance the fundamental property of ionic conductivity in solid materials,” explains Professor Chris Evans, who spearheaded the study. “The helix we are utilizing is the same structure found in biological peptides but applied here for non-biological applications.”
Typically, polymers adopt random shapes; however, by manipulating the polymer backbone, it is possible to create a helical structure similar to that of DNA. This arrangement results in a macrodipole moment—a significant separation of positive and negative charges. Along the helical length, the small dipole moments of each peptide unit combine to enhance the macrodipole, thereby increasing both the conductivity and the dielectric constant—an indicator of a material’s capacity to hold electrical energy—which, in turn, improves charge transport. The longer the peptide, the greater the conductivity of the helix.
Evans further notes, “These polymers maintain far greater stability compared to standard polymers—as the helix forms a very resilient structure. They can withstand high temperatures and voltages better than random coil polymers without deteriorating or losing their helical shape. We have not observed any signs of polymer breakdown before reaching their intended lifespan.”
Moreover, because these materials are derived from peptides, they can be environmentally broken down into individual monomer units using enzymes or acids once the battery has failed or approached the end of its operational life. This process allows for the recovery and reuse of the initial materials after separation, thereby decreasing environmental impact.
This research paper, titled “Helical peptide structure improves conductivity and stability of solid electrolytes,” appeared in Nature Materials.
Chris Evans also holds a position with the Materials Research Laboratory (MRL) and the Beckman Institute for Advanced Science and Technology at Illinois.
Other key contributors to this research include Yingying Chen, Tianrui Xue, Chen Chen, Seongon Jang, Paul Braun (all from the department of materials science and engineering, MRL, and the Beckman Institute for Advanced Science and Technology, Illinois), and Jianjun Cheng from the Materials Science and Engineering department at Westlake University in China.
This work received funding from the U.S. National Science Foundation and the U.S. Department of Energy’s Office of Basic Science, Division of Materials Science and Engineering.
