In situ quantification and visualization of lithium transport with neutrons

Abstract

A real-time quantification of Li transport using a nondestructive neutron method to measure the Li distribution upon charge and discharge in a Li-ion cell is reported. By using in situ neutron depth profiling (NDP), we probed the onset of lithiation in a high-capacity Sn anode and visualized the enrichment of Li atoms on the surface followed by their propagation into the bulk. The delithiation process shows the removal of Li near the surface, which leads to a decreased coulombic efficiency, likely because of trapped Li within the intermetallic material. The developed in situ NDP provides exceptional sensitivity in the temporal and spatial measurement of Li transport within the battery material. This diagnostic tool opens up possibilities to understand rates of Li transport and their distribution to guide materials development for efficient storage mechanisms. Our observations provide important mechanistic insights for the design of advanced battery materials. An in-depth study: In situ neutron depth profiling has been demonstrated to provide temporal and spatial measurement of Li concentration and visualization of its transposition upon charging and discharging of a Li-ion cell (see picture). The delithiation process shows the removal of Li near the surface, which leads to a decreased coulombic efficiency. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.