Electric vehicles (EVs) are increasingly becoming more appealing to customers who may want to maintain their ease of travel while cutting back on their reliance on fossil fuels in order to get around. Of course, to store the electricity that makes EVs go, they need batteries—and they need a lot of it.
This, however, presents a persistent problem for EVs: the batteries themselves present several points of failure for the car. For one, batteries are very heavy and are one of the many reasons why EVs are generally heavy despite their lack of a combustion engine.
Another glaring concern with EVs is the constant need to improve EV battery efficiency. As it stands, there are a lot of alternatives to standard lithium-based batteries, including those made from other materials.
Some even choose to improve on parts of the battery themselves, like replacing standard electrolytes with solid-state ones; these, however, also come with their own slew of problems. For one, these solid electrolytes are pretty fragile, making them pretty difficult to adapt as-is to an EV that may pass over several bumps on the road on the way to the grocery store—and that’s on top of their relatively expensive raw materials and fabrication processes required.
Luckily for us, Georgia Tech (GT) scientists are up to the task of solving the peculiar problem surrounding solid-state EV batteries. Their proposed solution, at first glance, looks as innovative as it is counterintuitive, as they designed battery electrolytes that are made of a rubbery material. Their novel research was published in the journal Nature.
“Most of the industry is focusing on building inorganic solid-state electrolytes. But they are hard to make, expensive, and are not environmentally friendly,” said George W. Woodruff School of Mechanical Engineering associate professor Seung Woo Lee, who also served as co-senior author of the paper.
Lee and their team instead looked to a rubbery organic polymer electrolyte. Their novel choice of material addresses the fragility issues common with traditional solid electrolytes, according to a Georgia Tech press release. Lee continued: “Rubber has been used everywhere because of its high mechanical properties, and it will allow us to make cheap, more reliable, and safer batteries.”
However, the part that does the actual conductive work is not the rubber matrix, but instead the succinonitrile conductive plastic crystals that are embedded within it. The conductive crystals facilitate lithium-ion transport using an “interconnected plastic crystal phase” within the elastomer, allowing the rubber material to serve its electrolytic function while at the same time exhibiting the flexibility and stability associated with the elastomer matrix.
According to the research team, the novel choice of material also prevents the formation of dendrites on the nearby electrodes, which can reduce the quality of contact between electrolyte and electrode while at the same time allowing the occurrence of unwanted side reactions within the battery if left unchecked.
The novel battery tech from Georgia Tech also exhibited an operating voltage of around 4.5 V at room temperature. It also possessed a specific capacity of around 93 mAh/g that remained stable across 1,000 charge cycles, according to New Atlas.
The Georgia Tech scientists believe that there’s much work to be done in terms of improvements. In the words of co-author and graduate researcher Michael Lee: “Higher ionic conductivity means you can move more ions at the same time. By increasing specific energy and energy density of these batteries, you can increase the mileage of the EV.”
References
- Irving, M. (2022, January 13). Rubbery electrolyte makes for longer-lasting, safer EV batteries. New Atlas. https://newatlas.com/energy/rubber-electrolyte-longer-lasting-safer-batteries/
- Lee, M. J., Han, J., Lee, K., Lee, Y. J., Kim, B. G., Jung, K.-N., Kim, B. J., & Lee, S. W. (2022). Elastomeric electrolytes for high-energy solid-state lithium batteries. Nature, 601(7892), 217–222. https://doi.org/10.1038/s41586-021-04209-4
- Rubber Material Holds Key to Long-lasting, Safer EV Batteries. (2022, January 12). Georgia Tech. http://news.gatech.edu/news/2022/01/12/rubber-material-holds-key-long-lasting-safer-ev-batteries
