Axial Si-Ge Heterostructure Nanowires as Lithium-Ion Battery Anodes.

Stokes, Killian; Flynn, Grace; Geaney, Hugh; Bree, Gerard; Ryan, Kevin M · Nano Lett · 2018

basic_science · Level V

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Abstract

Here, we report the application of axially heterostructured nanowires consisting of alternating segments of silicon and germanium with a tin seed as lithium-ion battery anodes. During repeated lithiation and delithiation, the heterostructures completely rearrange into a porous network of homogeneously alloyed Si<sub>1- x</sub>Ge <sub>x</sub> ligaments. The transformation was characterized through ex situ TEM, STEM, and Raman spectroscopy. Electrochemical analysis was conducted on the heterostructure nanowires with discharge capacities in excess of 1180 mAh/g for 400 cycles (C/5) and capacities of up to 613 mAh/g exhibited at a rate of 10 C.