Researchers from the Illinois Institute of Technology (IIT), Argonne National Laboratory, and the University of Illinois at Chicago have developed a room-temperature solid-state lithium-air battery that is rechargeable for 1,000 cycles with a low polarization gap and can operate at high rates. The composite polymer-ceramic solid-state electrolyte enables a four-electron redox process in the lithium-air battery. A paper on their work is published in the journal Science.
The battery design has the potential to store one kilowatt-hour per kilogram or highe—four times greater than lithium-ion battery technology—which would be transformative for electrifying transportation, especially heavy-duty vehicles such as airplanes, trains, and submarines, said Mohammad Asadi, assistant professor of chemical engineering at Illinois Institute of Technology and senior author.
A lithium-air battery based on lithium oxide (Li2O) formation can theoretically deliver an energy density that is comparable to that of gasoline. Lithium oxide formation involves a four-electron reaction that is more difficult to achieve than the one- and two-electron reaction processes that result in lithium superoxide (LiO2) and lithium peroxide (Li2O2), respectively. By using a composite polymer electrolyte based on Li10GeP2S12 nanoparticles embedded in a modified polyethylene oxide polymer matrix, we found that Li2O is the main product in a room temperature solid-state lithium-air battery.
The four-electron reaction is enabled by a mixed ion–electron-conducting discharge product and its interface with air. Lithium-air batteries have scope to compete with gasoline in terms of energy density. However, in most systems, the reaction pathways either involve one- or two-electron transfer, leading to lithium peroxide (Li2O2) or lithium superoxide (LiO2), respectively.
The composite electrolyte embedded with Li10GeP2S12 nanoparticles shows high ionic conductivity and stability and high cycle stability through a four-electron transfer process.