ZHANG Meng (1996-), male, Master candidate. E-mail: 1125213289@qq.com
Silicon has become the most promising anode material for lithium-ion batteries since its theoretical lithium intercalation capacity is as high as 4 200 mA·h/g. However, its commercial application as a negative electrode for Li-ion batteries is limited due to the huge volume expansion (≥300%) during intercalation and delithiation. In this paper, a C@Si/C silicon-based composite anode was prepared by an electrospinning technique with carbon source precursor coating. The phase structure and microstructure of the material were characterized by X-ray diffraction and scanning electron microscopy. The change of the quality of the obtained material after polyvinypyrrolidone coating with temperature was investigated by thermo-gravimetric analysis. Graphite transformation degree of the silicon-based negative electrode material obtained after carbonization was determined by Raman spectroscopy. The prepared silicon-based anode materials were analyzed by galvanostatic charge-discharge, cyclic voltammetry and alternating current impedance spectroscopy. The results show that the electrochemical performance of the carbon-coated electrospun Si/C fibers is improved compared to the uncoated fibers. At a current density of 0.1 A/g, the first discharge capacity can reach 1 401.4 mA·h/g, the first coulombic efficiency is as high as 70.22%, and the capacity remains at 582.6 mA·h/g after 100 cycles. The results of rate test show that after a large current density test of 1.0 A/g, C@Si/C silicon-based composite anode still has a reversible capacity of 622.2 mA·h/g at a current density of 0.1 A/g.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |