Sn Alloy and Graphite Addition to Enhance Initial Coulombic Efficiency and Cycling Stability of SiO Anodes for Li-Ion Batteries

Abstract

Silicon monoxide (SiO) has aroused increased attention as one of the most promising anodes for high-energy density Li-ion batteries. To enhance the initial Coulombic efficiencies (ICE) and cycle stability of SiO-based anodes, a new facile composition and electrode design strategy have been adapted to fabricate a SiO–Sn–Co/graphite (G) anode. It achieves a unique structure where tiny milled SiO–Sn–Co particles are dispersed among two graphite layers. In this hybrid electrode, Sn–Co alloys promoted Li+ extraction kinetics, and the holistic reversibility of SiO and graphite enhanced the electrical conductivity. The SiO–Sn–Co/G electrode delivered an average ICE of 77.6% and a reversible capacity of 640 mAh g−1 at 800 mA g−1, and the capacity retention was above 98% after 100 cycles, which was much higher than that of the SiO with an ICE of 55.3% and a capacity retention of 50%. These results indicated that this was reliable method to improve the reversibility and cycle ability of the SiO anode. Furthermore, based on its easy and feasible fabrication process, it may provide a suitable choice to combine other alloy anodes with the graphite anode.