High-yield synthesis of ultrathin silicon nanosheets by physical grinding enables robust lithium-ion storage

Abstract

Ultra-thin two-dimensional (2D) silicon nanosheets (SiNSs) have potential applications in electronic, energy storage, and energy conversion devices owing to their unique properties. However, high-yield and large-scale manufacturing of high-quality ultra-thin 2D SiNSs remains a great challenge. This report describes a simple, high-yield (>98%), and large-scale method for preparing ultra-thin 2D SiNSs. The developed approach improves the yield of SiNSs (thickness < 5 nm) by controlling the interaction force between the Si ingot and the abrasive grains during the diamond wire grinding process. The ultra-thin SiNSs deliver enhanced tap density and a limited variable solid electrolyte interphase growth interface. A dynamic chemical vapor deposition technique is carried out to increase the uniformity of the carbon coating on the ultra-thin SiNSs. Lithium-ion batteries employing SiNS-carbon composite anodes exhibit ultra-high initial Coulombic efficiency (88.1%) at a high Si content (79%). The full battery constructed with the fabricated SiNS-carbon composite anode and a commercial LiFePO4 cathode exhibits strong stability (1C over 600 cycles with a capacity retention rate > 80%). The results presented herein confirm the significant potential applicability of the developed method for synthesizing ultra-thin SiNSs with carbon coatings.