From solid waste to a high-performance Li3.25Si anode: towards high initial Coulombic efficiency Li–Si alloy electrodes for Li-ion batteries

Abstract

As a promising anode material for next-generation high-energy density lithium-ion batteries (LIBs), one of the main technical issues for silicon (Si) electrodes is the low initial Coulombic efficiency (ICE). By a pre-lithiation process, preparation of lithium–silicon (Li–Si) alloy electrodes can efficiently improve the ICE, thus leading to excellent electrochemical performance. Herein, with solid wastes as precursors, we report a cost-efficient approach for the fabrication of Li_3.25Si anode materials via simple magnesiothermic reduction and then mechanical alloy reaction methods, combining the advantages of low-cost and high ICE. The prepared Li_3.25Si@acetylene black (Li_3.25Si@A) electrode exhibits excellent electrochemical performance with a high reversible capacity of 1138.9 mA h g⁻¹ over 90 cycles at a current density of 100 mA g⁻¹ and its ICE is as high as 107.7%, which is superior to that of the commercial Li_3.25Si@A electrode. With a simple and low-cost manufacturing process and high ICE, the fabrication process will be definitely meaningful in achieving low-cost and high-capacity anode materials with a prolonged cycle life.