Abstract
Thetheoretical capacity of the silicon electrode is very high, but the largevolume change of Si during the charge and discharge processes leads to a fastcapacity fading and thus a poor cycling stability. Here, in order to overcomethis shortcoming, a new method for preparing silicon electrode materials wasproposed. We employed a facile ChemicalVapor Deposition (CVD)process to produce uniform carbon layer to cover the silicon spheres, etched aspace between the carbon layer and the silicon nucleus to accommodate theexpansion of silicon during charging and discharging, and thus a well-designedchain-like Si@void@Celectrode material was prepared. The thickness of the carbon shell was tunedsimply by adjusting CVD deposition time. The stability of such siliconelectrode was proved to be significantly enhanced. By a comparative study on Si@void@C,Si@Cand the commercial pure Si without carbon coating, we have demonstrated thatthe thin but stable carbon shell and the rationally designed void space in the Si@void@Cstructure have greatly positive influences on the electrochemical performance.As a result, the chain-like Si@void@C-15 exhibits a reversible capacity of983mAh g−1 after 200 cycles and a highcapacity retention up to 94%, indicating an excellent cycling stability. Goodrate performance is also demonstrated.
Thetheoretical capacity of the silicon electrode is very high, but the largevolume change of Si during the charge and discharge processes leads to a fastcapacity fading and thus a poor cycling stability. Here, in order to overcomethis shortcoming, a new method for preparing silicon electrode materials wasproposed. We employed a facile ChemicalVapor Deposition (CVD)process to produce uniform carbon layer to cover the silicon spheres, etched aspace between the carbon layer and the silicon nucleus to accommodate theexpansion of silicon during charging and discharging, and thus a well-designedchain-like Si@void@Celectrode material was prepared. The thickness of the carbon shell was tunedsimply by adjusting CVD deposition time. The stability of such siliconelectrode was proved to be significantly enhanced. By a comparative study on Si@void@C,Si@Cand the commercial pure Si without carbon coating, we have demonstrated thatthe thin but stable carbon shell and the rationally designed void space in the Si@void@Cstructure have greatly positive influences on the electrochemical performance.As a result, the chain-like Si@void@C-15 exhibits a reversible capacity of983mAh g−1 after 200 cycles and a highcapacity retention up to 94%, indicating an excellent cycling stability. Goodrate performance is also demonstrated.
