Silicon Electrochemistry in Molten Salts

Silicon electrochemistry has the potential to advance sustainable energy solutions by offering environmentally friendly and secure technologies that can contribute to the low-carbon economy. Electrochemical methods use electrons directly as reducing agents, eliminating the need for harmful chemicals and offering simpler, one-step, process control. Silicon itself is the second most abundant element in the earth's crust, is nontoxic, and is a robust material offering high efficiencies in solar photovoltaics. As such, silicon currently dominates the solar energy market and could continue to do so for the next few decades. This review summarizes recent achievements in the molten salt electrochemistry of silicon, highlighting subjects of technological significance such as the production of silicon by silica electro-deoxidation, the formation of photoactive layers, silicon electrorefining, and the synthesis of semiconductors as well as nanostructures for energy storage applications. The review highlights future opportunities and challenges such as the production of highly pure silicon, the creation of carbon-free anodes for oxygen production, and silicon electrodeposition from gaseous precursors.