Silicon Nanowires as Anodes for Lithium‐Ion Batteries: Full Cell Modeling

Silicon (Si) anodes attract a lot of research attention for their potential to enablehigh-energy density lithium-ion batteries (LIBs). Many studies focus on nano-structured Si anodes to counteract deterioration. Herein, LIBs are modeled withSi nanowire anodes in combination with an ionic liquid (IL) electrolyte. On theanode side, elastic deformations to reflect the large volumetric changes of Si areallowed. With physics-based continuum modeling, insight into usually hardlyaccessible quantities like the stress distribution in the active material can beprovided. For the IL electrolyte, the thermodynamically consistent transporttheory includes convection as relevant transport mechanism. The volume-averaged 1dþ1d framework is presented and parameter studies are performed toinvestigate the influence of the Si anode morphology on the cell performance. Thefindings highlight the importance of incorporating the volumetric expansion of Siin physics-based simulations. Even for nanostructured anodes—which aresaid to be beneficial concerning the stresses—the expansion influences theachievable capacity of the cell. Accounting for enough pore space is important forefficient active material usage