Metal-induced crystallization of highly corrugated silicon thick films as potential anodes for Li-ion batteries.

Silicon has turned into one of the most promising anodes for high energy rechargeable Li-ion batteries. However, a huge volume expansion during alloying with Li always induces serious pulverization/delamination for microsized electrodes as well as undesired accumulation of solid electrolyte interphase (SEI). Many efforts have focused on various nanoengineering and binding strategies to construct integrated, robust ionic/electronic wiring networks but with a trade-off between active/inactive material ratio and performance retention. Here, we first apply a metal-induced crystallization (AIC) principle for immiscible metal/semiconductor systems (Si/Al bilayers in this work) to prepare microthick Si films consisting of a high density of isolated nanocolumns. This method furthermore brings about low temperature crystallization of initial amorphous Si and conformal coating of ion-conductive oxide to enhance the Li transport kinetics of bulk and interface. Both highly satisfactory capacity retention (1650 mAh/g after 500 cycles) and rate performance (∼1000 mAh/g at 8C) are achieved for such thick Si film anodes. This methodology can be used to prepare thick film samples with well-defined nanostructures but free of extra binder and conductive additives. It enables much higher area specific capacity than for inactive-component contained slurry samples and thin film samples. This postdeposition pore-creating can be extended to more alloying or conversion electrodes of thick films for high capacity Li/Na ion batteries.