Anisotropic lithiation behavior of crystalline silicon

Abstract

In this paper we demonstrate the anisotropic lithiation of silicon (Si). Therefore specimens with radiating Si beams were selectively covered with pure lithium (Li) and lithiation was investigated at different temperatures. Due to the radial arrangement, Si beams underwent a crystallographic orientation dependent lithiation. The experiments showed up to 40% faster lithiation in 〈110〉 crystallographic directions compared to 〈100〉 oriented Si, and a temperature dependence of the lithiation propagation with lithiation rates of up to 337 nm s−1 at 100 °C. These results were reflected in prior observation of 〈110〉-orientated Li–Si dendrites, formed after mechanical contact of Li with a Si device layer of a silicon-on-insulator wafer.