Rechargeable lithium-ion batteries have one big problem that researchers are dedicating a lot of time to: their cathodes. Now, a team from the University of Maryland, the Brookhaven National Laboratory, and the U.S. Army Research Lab claims to have made a breakthrough in solving the problem. Cathodes, unlike anodes, tend to have a very limited capacity. As one of the lead authors in the new research puts it, “Cathode materials are always the bottleneck for further improving the energy density of lithium-ion batteries.” So the team set out to improve the energy density of the cathode by using an unlikely material: iron. They used a new form of iron trifluoride, which is cheap, easy to come by, and environmentally friendly. More importantly, iron trifluoride can transfer more than one electron when the battery discharges and charges, which makes such a battery theoretically much more efficient than comparable ones. However, […]