When a battery operates or recharges, ions move between electrodes through a medium called the electrolyte. ORNL’s Zhijia Du led the team who developed new formulations of lithium salts with carbonate solvents to form an electrolyte that maintains better ion flow over time and performs well when high current heats up the battery during extreme fast charging.
Project partners tested battery pouch cells made at ORNL’s Battery Manufacturing Facility to prove the battery’s safety and cycling characteristics.
“We found this new electrolyte formulation basically triples the Department of Energy’s target for the lifespan of an extreme-fast-charging battery,” Du said.
Here is an exclusive Tech Briefs interview — edited for length and clarity — with Du.
Tech Briefs: What was the catalyst/inspiration for your work?
Du: Although Li-ion batteries for EVs have been developed for higher energy density, lower cost, and longer cycle life in the past two decades, EV is still a relatively small market for vehicle sales. One gap is the ability for EVs to fast charge so that it can help alleviate the “range anxiety.” DOE has a goal of reducing charge time to 15 minutes or less. Our research is inspired by the urge to develop a fast-charging technology to meet this goal.
Tech Briefs: I’m sure there were too many to count, but what was the biggest technical challenge you faced while developing this technology?
Du: Think of Li-ion batteries as a pumped-storage hydroelectricity. During charge, Li-ions need to be stored into the graphite anodes, just like water to be stored in an upper reservoir. Fast charge means Li-ions need to be moved from cathode (lower reservoir) to anode (upper reservoir) in a timely manner: 10 minutes. The electrolyte is the media that moves Li-ions in a battery. The current electrolyte system is not capable of high-flux movement of Li-ions. Therefore, we need to develop a new electrolyte system that has that capability.
Tech Briefs: Can you explain in simple terms how it’s so efficient?
Du: The newly developed electrolyte system is capable of moving Li-ions in high flux, so we can have a fully filled Li-ion reservoir in just 10 minutes.
Tech Briefs: You’re quoted as saying, “We found this new electrolyte formulation basically triples the Department of Energy’s target for the lifespan of an extreme-fast-charging battery.” So, how soon could we see this battery commercialized?
Du: The technology is ready to be licensed and interested parties can contact ORNL Tech Transfer. There are many ways for ORNL and industry to work together toward commercialization.
Tech Briefs: What are your next steps?
Du: Our plan for future research is to evaluate other aspects of the performance of this electrolyte formulation, including its operation at different temperatures, it's safety, etc.
Tech Briefs: Do you have any advice for engineers/researchers aiming to bring their ideas to fruition?
Du: “Failure is the beginning of success.” Don’t be afraid to fail. Failures are stepping stones to later success.