An overview on efforts to enhance the Si electrode stability for lithium ion batteries

This report summarizes the challenges and developments related to the cycle stability of Si anodes. It describes the two-component material concepts using polymer blends and the approaches to material optimization for more stable Si anodes. Since the anode behavior also depends strongly on the Si particle size (and in polymer mixtures no uniform Si particle size is given), the properties of the Si anodes depending on the Si particle size and the underlying fundamental processes at the solid-electrolyte interface were described shortly. Bicomponent silicon-based composites (carbon additives, inorganic nanoparticles and polymers) on the anode behavior were compared by two properties: specific capacity and cycle number of the anodes. This article focuses on Si-polymer blends where the polymer can act as a binder or/and as a solid-state electrolyte. To help further the understanding the role of polymer we have gathered together useful data from the literature on solubilities, flexibility and hardness for the polymers generally used. We offer a perspective for polymer hydrogels that will enable a promising material composition for stable Si anodes.