We have long been bothered by the poor lithium storage capability of the electrolytic silicon nanowires derived from electro-reduction of solid silica in molten salts (a and b). Such a puzzle is now tackled by Dr. Wei Weng via replacing solid silica feedstock with silica dissolved in molten salts. The merits of using dissolved silica precursors are highlighted by direct electrodeposition of thinner silicon nanowires (20 nm in diameter) with thinner surface oxide layers (1 nm in thickness) on carbon cloth or nickel foam (c and d).

Benefiting from the small size, ultrathin oxide layer and binder-free electrode configuration, the electrodeposited Si nanowires on carbon cloth therefore has a high initial Coulombic efficiency (>90%) and a reversible capacity of 711 mAh/g after 200 galvanostatic charge/discharge cycles at 1000 mA/g. This finding highlights that the molten salt electrolysis of soluble silica can be a customized preparation of Si for advanced Li-ion batteries. The above results are now accepted for publication in ACS Applied Energy Materials (DOI: 10.1021/acsaem.8b01870).