Electric-Car Batteries Made Safer and More Reusable Using Supramolecular Electrolytes From Organic Materials

As more people express environmental awareness in transportation, our modern technology shifts toward green energy, which is sustainable and affordable. For this reason, electric cars have captured the interest of consumers, and their global sales continue to get stronger every year.

In 2022, 10.5 million electric cars were sold, accounting for 14.2% of the total vehicle sales. It is even predicted to increase by 30% in 2030. As the global sales of electric vehicles (EVs) increase, there is also an increased need for critical materials used in manufacturing their batteries.

Challenges in Manufacturing Solid-State Batteries

Most companies prefer solid-state batteries (SSBs) to improve the safety of EVs. However, experts find it challenging to manufacture SSBs due to the issue of making conformal interfaces between solid electrolyte particles and active materials in battery electrodes.

Conventional interfacing strategies implement high temperatures and pressure to make composite electrodes from solid electrolytes and active materials. They are also used in assembling batteries, metal anodes, solid-electrolyte separators, and current collectors. Deconstructing SSBs to separate cathode and solid-electrolyte particles remains intensive, as does the recreation of cathodes and separators using recovered materials.

Due to the adhesive character of interphases created during thermal processing, this strategy makes SSBs challenging to recycle at the end of their life. For this reason, there is a need for solid electrolytes with properties that facilitate SSB manufacturing, deconstruction, and recycling while providing sustainable performance.

Designing Supramolecular Electrolytes

Users of EVs consider the long-term prospects to achieve safe and stable operation of large vehicle powertrains for heavy transport. Improving the chemical properties of SSBs is thus needed for resource recovery through chemical recycling. Experts find it challenging to achieve circularity and direct cathode recycling with all-inorganic SSBs, but they see prospects for soft solid-ion conductors that can meet the co-design criteria across the manufacturing process, during the use phase, and at the end of life.

A group of scientists from the Lawrence Berkeley National Laboratory addressed the challenge in SSBs by designing supramolecular organo-ionic (ORION) electrolytes. These enable the fabrication of high-quality SSBs and the recycling of their cathode at their end-of-life stage.

At typical SSB operating temperatures, the ORION conductors are viscoelastic solid electrolytes at -45 to 45 degrees Celsius. On the other hand, they are viscoelastic liquids upon reaching 100 degrees Celsius. While in the liquid state, ORION conductors demonstrate excellent wetting characteristics for both porous cathodes and lithium metal anodes. Consequently, they can also be fabricated using low-intensity thermal processing with conformal interfaces to both electrodes.

Analysis of ORION SSBs reveals 82% capacity retention after 100 cycles at a vehicle-relevant operating temperature of 45 degrees Celsius. They can be recovered at the end of life using a solvent process that allows direct cathode recycling. Furthermore, recycled ORION SSBs recovered 90% of their initial capacity, with the ability to sustain it for additional 100 cycles with 84% capacity retention.

Check out more news and information on Electric Vehicles in Science Times.