Inert Salt Assisted Magnesiothermic Reduction Process for the Synthesis of Crystallinity Controlled High-Performance SiOx Anode Material for Lithium-Ion Batteries

Abstract

Silicon sub oxides (SiOx) materials are considered as potential anode materials for next-generation high-energy lithium-ion batteries (LIBs) because of their high specific capacity and improved cyclic performance with the advantage of low operating voltage. Many parameters influence the performance anode material in lithium ion batteries, such as nano-size material, high surface area and crystalline structure. Especially crystallinity of Si is a significant factor for obtaining better performance because it directly affect the structural stability of Si anode during the electrochemical reactions. Crystallinity is directly controlled by the reaction temperature. Here we compared the effect of heat absorbent inner salt KCl and NaCl on the Si crystallinity. Crystallinity controlled D-SiOx anode material has been prepared by partial magnesiothermic reduction process using heat regulating inert salts KCl and NaCl for enhanced electrochemical properties. Anode prepared using KCl assisted shows low crystallinity of Si with remarkably improved reversible capacity and excellent cyclic stability as compared with NaCl assisted high crystalline Si. KCl assisted D-SiOx exhibited initial discharge and charge capacities of 2243 and 1862 mA h g-1, respectively, with an ICE of 83%. Moreover, it showed a stable cycle performance, maintaining a high capacity retention of up to 90% even after 200 cycles at 0.5C. Figure 1