Electrolyte Pulls “Double Duty” for Longer Lasting Batteries
Posted on: 04/28/2014
Researchers at Oak Ridge National Laboratory (ORNL) have developed a new and unconventional battery chemistry aimed at producing batteries that last longer than previously thought possible.
The team is challenging a long-held assumption that a battery’s three main components—the positive cathode, negative anode and ion-conducting electrolyte—can play only one role in the device. The electrolyte in the their new battery design actually has dual functions. It serves not only as an ion conductor but also as a cathode supplement. This cooperative chemistry, enabled by the use of an ORNL-developed solid electrolyte, delivers an extra boost to the battery’s capacity and extends the lifespan of the device.
“This bi-functional electrolyte revolutionizes the concept of conventional batteries and opens a new avenue for the design of batteries with unprecedented energy density,” said Chengdu Liang, ORNL staff scientist and TMS member.
The team demonstrated the new concept in a lithium carbon fluoride battery, considered one of the best single-use batteries because of its high energy density, stability, and long shelf life. When the researchers incorporated a solid lithium thiophosphate electrolyte, the battery generated a 26 percent higher capacity than what would be its theoretical maximum if each component acted independently. The increase, explains Liang, is caused by the cooperative interactions between the electrolyte and cathode.
“As the battery discharges, it generates a lithium fluoride salt that further catalyzes the electrochemical activity of the electrolyte,” Liang said. “This relationship converts the electrolyte—conventionally an inactive component in capacity—to an active one.”
The improvement in capacity could translate into years or even decades of extra life, depending on how the battery is engineered and used.
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