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New, higher-capacity materials are required in order to address the growing need for batteries with greater energy density and longer cycle life for modern applications. We present here a study of silicon-nanowire (SiNW) anodes, synthesized via a novel, catalysts free and scalable chemical vapor deposition (CVD) on stainless-steel mesh. This is a continuation to our previous paper (Harpak et al., Nano Lett. (2019) http://pubs.acs.org/doi/10.1021/acs.nanolett.8b05127) that describes the progress we recently made. The study is focused on the adaptation of the SiNW anode in various large-scale configurations. Our research efforts have resulted in the successful scale-up of the silicon anode from Si/Li half-cells with high areal capacity of 14 mAh cm-2, to coin cells with commercial cathodes, industrial 1/3AAA cells and proof-of-concept multilayered pouch cells. Testing of our anodes in cylindrical cells demonstrated the applicability of these anodes in commercial lithium-ion batteries that can run for hundreds of cycles, withstanding fast charge and subzero temperatures. An all-solid Si/polymer electrolyte/NCA cell is also demonstrated as a proof of concept (POC). We assign the major degradation mechanism of the SiNW anodes to the growth of the SEI thickness and impedance during cycling. We found that the depth of lithiation/delithiation and the voltage profile of the cell significantly affect cell's stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • We report on the application of nanothin parylene as an efficient artificial SEI for silicon anodes. • The deposition process can be controlled down to a thickness of 30 nm with excellent uniformity. • The parylene layer is extremely stable, chemically, electrochemically and mechanically. • Electrochemical studies reveal that the parylene F layer is superior to other parylene types. • The ultrahigh Si-content anodes (more than 10 mg/cm2) shown 95.5% capacity retention over 480 cycles. Here, we report on the application and characterization of parylene (poly p-xylylene) layers of nanometric thickness as a highly efficient artificial elastic SEI layer for three dimensional nanosilicon anodes. The simple deposition process creates an extremely conformal layer, even on complex 3D substrate geometries. The deposition process can be easily controlled down to thickness of 30 nm with excellent uniformity. The parylene nanothin layers were shown to be extremely stable, chemically, electrochemically and mechanically, while notably allowing the free diffusion of Li-ions into the Si underlying active layer permitted by the finite solvent diffusion through the polymeric layer. The elasticity of the organic parylene layer plays a key role in the applicability of parylene to act as an efficient artificial SEI structure, as it was shown to be capable to withstand the dramatic natural "breathing" effect of the underlying silicon nanostructures, without interruption to the active material volumetric changes, causing no additional stress on the silicon structures, while partially preventing and slowing the formation of a secondary SEI layer. Electrochemical characterization reveals that parylene VT-4 (parylene F) layer is superior to other parylene types, exhibiting >500 cycles with >75% capacity retention, dramatically improving the anode cycling life compared to bare silicon-based anodes, while not limiting the active material loading degree achievable. Importantly, the parylene layer efficacy in preserving the silicon active material is determined via 95.5% capacity retention at low c-rates. The simplicity, applicability and control of parylene deposition, along with its vast improvement of stability of bare silicon anodes, make it an excellent candidate for future applications as an efficient artificial SEI layer for next-generation silicon anodes and other active materials of interest. [ABSTRACT FROM AUTHOR]