Low-Temperature Molten-Salt Production of Silicon Nanowires by the Electrochemical Reduction of CaSiO.

Silicon is an extremely important technological material, but its current industrial production by the carbothermic reduction of SiO is energy intensive and generates CO emissions. Herein, we developed a more sustainable method to produce silicon nanowires (Si NWs) in bulk quantities through the direct electrochemical reduction of CaSiO , an abundant and inexpensive Si source soluble in molten salts, at a low temperature of 650 °C by using low-melting-point ternary molten salts CaCl -MgCl -NaCl, which still retains high CaSiO solubility, and a supporting electrolyte of CaO, which facilitates the transport of O anions, drastically improves the reaction kinetics, and enables the electrolysis at low temperatures. The Si nanowire product can be used as high-capacity Li-ion battery anode materials with excellent cycling performance. This environmentally friendly strategy for the practical production of Si at lower temperatures can be applied to other molten salt systems and is also promising for waste glass and coal ash recycling.