Low-Cost Fabrication of Silicon Nanowires by Molten Salt Electrolysis and Their Electrochemical Performances as Lithium-Ion Battery Anodes

The molten salt electrolytic method was introduced to prepare metallic silicon that simply utilizes SiO2 powder as the raw material and equimolar CaCl2-NaCl as the electrolyte under 1.8 V current at 700°C for 5 h. The electrochemically synthesized silicon was in the form of nanowire structures with average sizes of 90 nm in diameter and over 1 μm in length. The current efficiency and specific energy consumption of producing silicon nanowires were calculated to be 79.2% and 8.703 kWh/kg, respectively. Benefiting from the synthesized nanowire structure, the silicon anode exhibited a high initial discharge-specific capacity of 3348.1 mAh/g with an initial coulombic efficiency of 85.2%. The present research provides a straightforward idea to show the feasibility of synthesizing silicon-based material by the molten salt electrolytic method and to introduce the application of synthesized silicon nanowires to lithium-ion battery systems.