Silicon is one of the most promising anode materials for lithium-ion batteries(LIBs), but it suffers from pulverization and hence poor cycling stability due to the large volume variation during lithiation/delithiation...Silicon is one of the most promising anode materials for lithium-ion batteries(LIBs), but it suffers from pulverization and hence poor cycling stability due to the large volume variation during lithiation/delithiation. The core-shell structure is considered as an effective strategy to solve the expansion problem of silicon-based anodes. In this paper, the double-shell structured Si@SnO_(2) @C nanocomposite with nano-silicon as the core and SnO_(2) , C as the shells is synthesized by a facile hydrothermal method.Structural characterization shows that Si@SnO_(2) @C nanocomposite is composed of crystalline Si, crystalline SnO_(2) and amorphous C, and the contents of them are 42.1wt%, 37.8 wt% and 20.1 wt%, respectively. Transmission electron microscope(TEM) observations confirm the double-shell structure of Si@SnO_(2) @C nanocomposite, and the thicknesses of the SnO_(2) and C layers are 20 and 7 nm. The Si@SnO_(2) @C electrode exhibits a high initial discharge capacity of 2777 mAh·g^(-1)at 100 mA·g^(-1)and an excellent rate capability of 340 mAh·g^(-1)at 1500 mA·g^(-1). The outstanding capacity retention is 50.2% after 300 cycles over a potential of 0.01 to 2.00 V(vs. Li/Li+) at 500 mA·g^(-1). The resistance of solid electrolyte interphase(SEI) film(Rf) and charge transfer resistance(Rct) of Si@SnO_(2) @C are 7.68and 0.82 Ω, which are relatively smaller than those of Si@C(21.64 and 2.62 Ω). It is obviously seen that the SnO_(2) shell can reduce the charge transfer resistance, leading to high ion and electron transport efficiency in the Si@SnO_(2) @C electrode. The incorporation of SnO_(2) shell is attributed to the enhanced rate capability and cycling performance of Si@SnO_(2) @C nanocomposite.展开更多
基金financially supported by GRINM Science and Technology Innovation Fund (Nos. 2020DY0109 and 57222001)the Opening Project Fund of Materials Service Safety Assessment Facilities (No. MSAF-2021-001)Guangdong High Level Innovation Research Institute (No. 2021B0909050001)。
文摘Silicon is one of the most promising anode materials for lithium-ion batteries(LIBs), but it suffers from pulverization and hence poor cycling stability due to the large volume variation during lithiation/delithiation. The core-shell structure is considered as an effective strategy to solve the expansion problem of silicon-based anodes. In this paper, the double-shell structured Si@SnO_(2) @C nanocomposite with nano-silicon as the core and SnO_(2) , C as the shells is synthesized by a facile hydrothermal method.Structural characterization shows that Si@SnO_(2) @C nanocomposite is composed of crystalline Si, crystalline SnO_(2) and amorphous C, and the contents of them are 42.1wt%, 37.8 wt% and 20.1 wt%, respectively. Transmission electron microscope(TEM) observations confirm the double-shell structure of Si@SnO_(2) @C nanocomposite, and the thicknesses of the SnO_(2) and C layers are 20 and 7 nm. The Si@SnO_(2) @C electrode exhibits a high initial discharge capacity of 2777 mAh·g^(-1)at 100 mA·g^(-1)and an excellent rate capability of 340 mAh·g^(-1)at 1500 mA·g^(-1). The outstanding capacity retention is 50.2% after 300 cycles over a potential of 0.01 to 2.00 V(vs. Li/Li+) at 500 mA·g^(-1). The resistance of solid electrolyte interphase(SEI) film(Rf) and charge transfer resistance(Rct) of Si@SnO_(2) @C are 7.68and 0.82 Ω, which are relatively smaller than those of Si@C(21.64 and 2.62 Ω). It is obviously seen that the SnO_(2) shell can reduce the charge transfer resistance, leading to high ion and electron transport efficiency in the Si@SnO_(2) @C electrode. The incorporation of SnO_(2) shell is attributed to the enhanced rate capability and cycling performance of Si@SnO_(2) @C nanocomposite.
