Photovoltaic Monocrystalline Silicon Waste‐Derived Hierarchical Silicon/Flake Graphite/Carbon Composite as Low‐Cost and High‐Capacity Anode for Lithium‐Ion Batteries

Abstract

AbstractThe silicon/flake graphite/carbon (Si/FG/C) composite with hierarchical structure has been designed, fabricated and used as anode material of lithium ion battery via a facile and attainable high temperature calcination method using photovoltaic monocrystalline silicon waste as silicon source. The physical characterization of the hierarchical Si/FG/C composite is conducted by X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results reveal that the nano‐Si and flake graphite are effectively and homogenously encapsulated by pyrolytic carbon and form the Si/FG/C composite with hierarchical structure. The electrochemical measurements show that the Si/FG/C composite delivers a high initial specific capacity of 634 mAh g−1 and excellent Coulombic efficiency of 99.6 % at 0.2 C with a capacity retention of 82 % after 200 cycles, which is apparently higher than the capacity retention (57.96 %) of the same composition Si/C composite. Besides, the Si/FG/C composite behaves outstanding cycle stability and rate capability.