液相置换法制备硅/碳复合材料及其储锂性能

Preparation of Silicon/Carbon Composite by Liquid Phase Displacement Method and Its Lithium Storage Performance

  • 摘要: 通过镁热还原SiO2实现了纳米硅的制备,随后通过液相置换法将其与葡萄糖复合经过热处理获得硅/碳复合材料(Si/C)。在将制备的材料作为锂离子电池的负极材料,测试发现该材料展示了优异的循环性能(在100 mA/g的电流密度下,循环50次的比容量能维持在800 mAh/g左右)、高的倍率性能(在4 200 mA/g的电流密度下保持在385 mAh/g的比容量)和不错的循环稳定性(在840 mA/g的电流密度下,循环120次其容量亦能维持在约459 mAh/g),远高于纯硅和纯碳的容量。可见碳的介入有效改善了硅的导电性,提升了其储锂性能,为Si/C复合材料在高性能锂离子电池的应用提供了一种新的策略。

     

    Abstract: Novel liquid phase displacement method was developed to prepare a silicon/carbon composite (Si/C) by directly reacting nano silicon (which was synthesized by magnesium thermal reduction of SiO2) and glucose. Subsequently, When the Si/C is used as the anode material for LIBs, the batteries display favorable discharge capacities (800 mAh/g after 50 cycles at 100 mA/g), high-rate performance (385 mAh/g at 4 200 mA/g), and excellent stable cyclability (459 mAh/g after 120 cycles at 840 mAh/g). Which is much higher than the discharge capacity of pure silicon and carbon. Such results indicate that the intervention of carbon effectively conductivity improves of Si for the lithium storage performance increasing. Notably, the research might provide a new strategy for the application of Si/C composite materials in high-performance LIBs.

     

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