Formation of Heterostructured Silicon Thick Films in Atmospheric-Pressure Very High-Frequency Plasma Toward the Application to Lithium Ion Battery Anode

The superiority of silicon (Si) film performance as anode material in the rechargeable battery technologies is tormented by the huge volume expansion during cycle. The combined structure of a microcrystalline Si with high porous/defect density and an isotropic amorphous Si has been proposed as a feasible solution. Our own deposition process using atmospheric-pressure (AP) plasma excited by very high-frequency (VHF) power has managed to create a non-composite Si film with gradient phase along thickness direction. This work investigates the formation of heterostructured Si thick film and its capability toward the application to the Lithium-ion Batteries (LIBs) anode. It is highly indicated that a slower gas flow rate and/or a larger power input cause the nanoparticle formation in the AP-VHF plasma to occur more actively, which significantly influenced the development of a crystalline layer with a high density of grain boundaries. The promising electrochemical performance imply a great potential of heterostructured Si as LIBs anode.