A research team at Northwestern University has found a way to stabilize the new battery, which has a high recording capacity.

　　A research team at Northwestern University has found a way to stabilize the new battery, which has a high recording capacity. Based on lithium manganese oxide cathodes, this breakthrough can more than double the battery life of smartphones and battery-powered cars.

　　"This battery electrode has achieved one of the highest capacities ever reported for all transition metal oxide-based electrodes, and it is more than twice the current capacity of materials in mobile phones or laptops," Jerome B. Christopher Wolferton Say. Professor Cohen, Department of Materials Science and Engineering, Northwest McCormick School of Engineering, who is in charge of the research. "This high capacity will represent a huge improvement in lithium-ion batteries for electric vehicles."

　　Lithium ion batteries work by shuttle lithium ions back and forth between anode and cathode. The cathode is made of a compound containing lithium ions, transition metals and oxygen. When lithium ions move from the anode to the cathode and back, the transition metal (usually cobalt) effectively stores and releases electrical energy. Then, the capacity of the cathode is limited by the number of electrons in the transition metal participating in the reaction.　　 A French research team first reported a large-capacity lithium manganese oxide compound in 2016. By replacing the traditional cobalt with cheaper manganese, the team developed a cheaper electrode that more than doubled its capacity. But this is not without challenges. In the first two cycles, the performance of the battery has dropped significantly, and researchers do not think it is commercially viable. They also did not fully understand the chemical sources of bulk or degradation.

　　After 　　 Wolverton’s team described the atomic diagram of the cathode atoms in detail, they discovered the reason behind the high capacity of the material: it forces oxygen to participate in the reaction process. In addition to transition metals, batteries have a higher capacity to store and use lithium by using oxygen to store and release electrical energy.

　　Next, the Northwest team turned their attention to stabilizing the battery to prevent its rapid degradation.

　　"With knowledge of the charging process, we used high-throughput calculations to scan the periodic table of elements and found new ways to synthesize this compound with other elements that can improve battery performance," said ZhenpengYao, the first author of the paper and Former Ph.D. Student at Wolferton Lab.

　　The calculation determined two elements: chromium and vanadium. The team predicts that mixing the element with lithium manganese oxide will produce a stable compound that will maintain the unprecedented high capacity of the cathode. Next, Wolverton and his collaborators will test these theoretical compounds experimentally in the laboratory.

　　This research was supported by the Electrochemical Energy Science Center, which is the DE-AC02-06CH11357 Energy Frontier Research Center funded by the Department of Basic Energy Science, Office of Science, Department of Energy. Yao, who is currently a postdoctoral researcher at Harvard University, and SooKim, a postdoctoral researcher at MIT, are both former members of the Wolverton laboratory and served as the first author of the paper.