Effective disproportionation of SiO induced by Na2CO3 and improved cycling stability via PDA-based carbon coating as anode materials for Li-ion batteries

Abstract

In order to improve the initial coulombic efficiency (ICE) and cycle performance of SiO, in this study, the disproportionation reaction of commercial SiO is performed with the assistance of Na₂CO₃ under high temperatures. A polydopamine-based carbon is then in situ formed on the surface of the mixture (d-SiO-G) of disproportionated-SiO and graphite. It is found that an appropriate amount of Na₂CO₃ can effectively enhance the ICE of the commercial SiO due to the formation of Si, SiO₂, and silicate; the mass ratio of d-SiO-G to the dopamine monomer is the important factor in influencing the cycling stability of the d-SiO-G@C composite. Due to the synergistic effect of graphite and the polydopamine-based carbon layer, the ICE for the d-SiO-G@C composite is 72.6%, and its capacity retention reaches 86.2% after 300 cycles, which is 11% higher than that of d-SiO-G. The modification method is an effective strategy for SiO materials in commercial applications.