Pacific Northwest National Laboratory (PNNL), a U.S. Department of Energy (DOE) managed laboratory, is currently working on a material that could allow more renewable energy to be stored within lithium-sulfur batteries, increasing the distance an electric vehicle (EV) could travel on one charge. The material is a powderized nanomaterial called a metal organic framework, which reseachers are currently testing at the Richland, Wash., facility.
Metal organic frameworks (MOFs) are crystal-like compounds made of metal clusters connected to organic molecules, or linkers. Together, the clusters and linkers assemble into porous 3-D structures. MOFs can contain a number of different elements. PNNL researchers chose the transition metal nickel as the central element for this particular MOF because of its strong ability to interact with sulfur.
"Lithium-sulfur batteries have the potential to power tomorrow's electric vehicles, but they need to last longer after each charge and be able to be repeatedly recharged," said materials chemist Jie Xiao at PNNL. "Our metal organic framework may offer a new way to make that happen."
EVs are typically powered by lithium-ion batteries, which can limit range due to the chemistry the batteries. This results in EV range anxiety, with drivers worrying about how far they can go before needing a charge. Lithium-sulfur battery, which can hold as much as four times more energy per mass than lithium-ion batteries, would enable electric vehicles to drive farther on a single charge, as well as help store more renewable energy. On the down side, lithium-sulfur batteries have a much shorter lifespan because they can't currently be charged as many times as lithium-ion batteries.