Researchers at the Department of Energy’s Oak Ridge National Laboratory have developed a new and unconventional battery chemistry aimed at producing batteries that last longer than previously thought possible. In a study published in the Journal of the American Chemical Society, ORNL researchers challenged 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 team’s new battery design 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 ORNL’s Chengdu Liang. 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 ORNL 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.