A battery with an ability to function at cold temperatures could make for electric vehicles with greater ranges in cold climates. Conversely, a battery that can safely operate at higher temperatures could eliminate the need for cooling systems to prevent overheating, in addition to other advantages.
“You need high temperature operation in areas where the ambient temperature can reach the triple digits and the roads get even hotter,” explained study author Zheng Chen. “In electric vehicles, the battery packs are typically under the floor, close to these hot roads. Also, batteries warm up just from having a current run through during operation. If the batteries cannot tolerate this warmup at high temperature, their performance will quickly degrade.”
The dibutyl ether electrolyte developed by the UC San Diego team prevents these issues, even at high and low temperatures. The batteries they tested had much longer cycling lives than a typical lithium-sulfur battery. “Our electrolyte helps improve both the cathode side and anode side while providing high conductivity and interfacial stability,” said Chen.
The team also engineered the sulfur cathode to be more stable by grafting it to a polymer. This prevents more sulfur from dissolving into the electrolyte.