Materials experts have developed polymer capacitors by incorporating a chemical reaction to achieve long polymer chains of sulfate molecules called polysulfates which have unique energy storage properties that can help improve the efficiency of integrated power systems.

Developed at the Lawrence Berkeley National Laboratory, these capacitors are based on fabricated films making them highly resistant to increased temperatures and voltage.

In the experiment, polysulfates with enhanced thermal properties were cast onto flexible thin films.

Using the new sulfur-fluoride exchange (SuFEX) chemical reaction, the experts invented a new synthesis method and studied the link between polymer structure and the properties of materials.

The scientists at the Berkeley Lab collaborated with the U.S.-based non-profit medical research facility Scripps Research and used the chemical reaction to boost the dielectric properties of the materials used in capacitors, which can be commercialized as power capacitors in the future for energy storage.

A dielectric material is an electrical insulator such as silicon dioxide, which is widely used in semiconductor fabrication. Dielectric polymers with ultrahigh power density are largely used in modern electronics and power systems.

The chemical reaction is pioneered by K. Barry Sharpless, a two-time Nobel laureate in Chemistry and chemist at Scripps Research.

Better storage performance with aluminum oxide

The study published in the scientific journal Joule said that the Berkeley and Scripps teams used the reaction to maintain the stability of the films cast with polysulfates while retaining the electrical insulating properties of newly designed capacitors.

“Several commercial and lab-generated polymers are known for their dielectric properties, but polysulfates had never been considered. The marriage between polysulfates and dielectrics is one of the novelties here,” said He Li, a postdoctoral researcher in the Molecular Foundry and in Berkeley Lab’s Materials Sciences Division, and lead author of the study.

The scientists introduced thin layers of aluminum oxide (Al2O3) that were deposited onto the thin films of the material which boosted the energy and storage performance of their new device with polysulfate-casted capacitors.

They discovered that the fabricated capacitors showed excellent mechanical flexibility while withstanding strong electric fields of over 750 million volts per meter.

Polysulfate cast polymer capacitors vs commercial capacitors

The new polymer-based capacitor device cast with polysulfate performed efficiently at high temperatures of up to 150 degrees Celsius, compared to the commercial polymer capacitors available currently that function stably at temperatures lower than 120 degrees Celsius.

The experts found that the polymer strikes a balance of electrical, thermal, and mechanical properties, likely due to the sulfate linkages introduced by the click chemistry reaction.

According to the researchers, polysulfates are potential contenders to enable polymer dielectrics which would help develop power capacitors. Such capacitors will help improve the energy efficiency and reliability of integrated power systems in applications like electrified transportation.

Scientists are now studying the chemical reaction to enable the commercialization of such power capacitors which can evidently enhance the performance and efficiency of electric vehicles.

“Our work adds a new class of electrically robust polymers to the table. It opens many possibilities for the exploration of more robust, high-performing materials. We’re continuously pushing the envelope of thermal and electrical properties, and accelerating the lab-to-market transition.,” said Yi Liu, senior author of the study and a chemist at Berkeley Lab.

In another research, scientists at the Indian Institute of Nano Science and Technology developed a new material for supercapacitors or pseudocapacitors. The material they said offers a low-cost, highly scalable energy storage solution, and can store electrical energy by electron charge transfer while it can be used as an alternative to batteries.

Last July, scientists at the Indian Institute of Technology, Kharagpur used nanomaterials and developed sodium-ion (Na-ion) batteries and supercapacitors that can be integrated into e-cycles for rapid charging. The researchers synthesized sodium iron phosphates and sodium manganese phosphates to obtain sodium-ion batteries and supercapacitors.