Energy density requirements for larger-scale applications require higher storage capacity from both anodes and cathodes.  Among other group IV elements, Sn, with its relatively high theoretical specific capacity of 959 mAh/g is a promising alternative anode material.  During the alloying/de-alloying process with lithium, Sn experiences significant capacity fade often attributed to volumetric expansions and amorphization of the material.  Improvements in the complex architectures such as nanowires, 3D architecture, inactive core/active shell structures are often attributed to enhanced accommodation of the transformations that occur during cycling.  However, the transport properties of lithium and their resulting distribution within the material are largely inferred using ex situ and often invasive techniques.  This paper will discuss recent efforts in using neutron depth profiling (NDP) to probe the distribution and dynamics of Li transport in Sn anodes during lithiation and delithiation processes.  A real-time quantification of Li transport using a non-destructive neutron method to measure the Li distribution upon charge and discharge of a Li-ion cell is reported here.  In situ Neutron Depth Profiling (NDP) provides temporal and spatial measurement of Li and visualization of its transposition to guide materials development for efficient storage.  Using in situ NDP, we probed the onset of lithiation in a model Sn electrode and visualized the enrichment of Li atoms on the surface while monitoring the propagation of Li into the bulk.

In situ characterization of Li transport in Li<sub>x</sub>Sn<sub>y</sub> anodes with neutrons

248th National Meeting (2014)

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In situ characterization of Li transport in LixSny anodes with neutrons

In situ characterization of Li transport in Li_xSn_y anodes with neutrons