Constructing triple-protected Si/SiOx@ZnO@C anode derived from volatile silicon waste for enhanced lithium storage capacity

Abstract

Silicon anode is deemed to be one of the most promising anode materials and has attracted wide attention from all walks of life. However, its commercial application is severely limited owing to the high cost, serious volume expansion, and poor electrical conductivity. Herein, Si/SiOx nanoparticles were successfully prepared by sand milling the low-cost volatile deposited silicon waste from electron beam refining polycrystalline silicon. Furthermore, the atomic layer deposited (ALD) zine oxide on Si/SiOx nanoparticles enhances the integrity of the electrode structure and provides a steady solid electrolyte layer (SEI). The outer layer is wrapped by a uniform carbon shell to restrict the volume expansion and boost the conductivity of the electrode during lithiation/delithiation. Impressively, lithium-ion batteries (LIBs) employing the Si/SiOx@ZnO@C anodes display excellent rate performance (up to 844.48 mAh g−1 at 2 A g−1) and cycle stability (912.7 mAh g−1 at 1A g−1 over 50 cycles). Moreover, the Si/SiOx@ZnO@C electrode exhibits high initial coulombic efficiency (76.8 %) and the reversible specific capacity maintains at 846 mAh g−1 over 200 cycles with a current density at 0.5 A g−1. The improvement is ascribed to the synergistic effect of triple-protected layer that effectively enhances the stability of SEI and the conductivity of the electrode. This work not only opens a novel and economic strategy for the manufacture of high-performance silicon-based anode but also furnishes an original approach for recycling and resource utilization of silicon waste.