Researchers in Switzerland have developed a silicone-based stretchable polymer electrolyte that could improve the performance and comfort of next-generation solid-state batteries, particularly for flexible and medical applications.
Scientists at the Swiss Federal Laboratories for Materials Science and Technology (Empa), working in the Laboratory for Functional Polymers, designed the new electrolyte using a modified silicone polymer. The innovation could enable safer, more adaptable battery designs compared with conventional solid-state electrolytes.
Unlike most solid-state battery electrolytes, which are typically rigid, the newly developed material is soft and stretchable. The base polymer used in the study is polysiloxane, commonly known as silicone. While silicone provides excellent elasticity, it is naturally non-polar, meaning it cannot easily dissolve charged particles such as ions—an essential requirement for battery electrolytes.
To overcome this limitation, the research team led by Dorina Opris introduced functional chemical groups into the polymer backbone. This modification allows the material to conduct ions effectively while maintaining its elastic properties.
According to Opris, current batteries used in medical implants—such as pacemakers—are often rigid and uncomfortable for patients. The newly developed polymer could address this challenge by enabling softer, flexible batteries. In addition to functioning as an electrolyte, the material can also act as a binder for cathode materials.
The electrolyte is currently being tested in various battery prototypes, including button cells. Researchers believe that with suitable electrode materials, the polymer could be used to manufacture fully flexible batteries for a wide range of applications.
Empa researcher Can Zimmerli noted that the flexible polymer can be paired with different cathode active materials, making it adaptable for diverse battery technologies.
Beyond flexibility and safety, the electrolyte also offers manufacturing advantages. The material can be processed into ultra-thin films only a few micrometers thick and is scalable for industrial production. If produced at scale, it could also be more cost-effective than conventional solid polymer electrolytes.
The research team is now working to further enhance the material’s ionic conductivity while seeking industrial partners to support commercialization of the technology.
In most conventional batteries, electrolytes are flammable liquids. Solid-state batteries replace these liquids with solid materials, improving safety and enabling the use of alternative electrode materials such as lithium metal anodes. This design can significantly increase energy density, allowing batteries to store more electricity per volume—an advantage for applications ranging from electric vehicles to portable electronics.