多孔硅/石墨烯锂离子电池负极材料的制备及其电化学性能研究

Preparation and electrochemical properties of porous silicon/graphene as LIB anodes

以Al-20Si合金为原料制备多孔硅粉体材料和多孔硅/石墨烯复合材料,并将其用作锂离子电池的负极材料。采用盐酸浸蚀合金的方法制备多孔硅粉体材料,通过借助超声向硅基材料中分别添加不同含量的石墨烯(0,5%,10%,15%,20%,25%)制备多孔硅/石墨烯复合材料。实验结果显示,在多孔硅基材料中添加10%石墨烯的电化学性能最好,首次充放电容量为2 552 mAh/g,最后稳定在540 mAh/g。首次充放电效率为78.5%,循环至第5次后,后续充放电过程中效率维持在98%左右。石墨烯添加量超过10%后。随着添加量的增加性能逐渐下降。石墨烯的加入会使充放电比容量有所降低,但会使硅的循环稳定性增加。

In this paper, a porous silicon powder material and a porous silicon/graphene composite material were prepared by using Al-20Si alloy as a raw material, and used as a negative electrode material for lithium ion batteries. A porous silicon powder material was prepared by etching an alloy with hydrochloric acid. Porous silicon/graphene composites were prepared by ultrasonically adding different amounts of graphene (0, 5%, 10%, 15%, 20%, 25%) to a silicon-based material, respectively. The experimental results show that the addition of 10% graphene to the porous silicon-based material had the best electrochemical performance. The first charge and discharge capacity was 2 552 mAh/g, and the charge and discharge capacity was finally stabilized at 540 mAh/g. The first charge and discharge efficiency was 78.5%. After the five cycles, the efficiency during subsequent charging and discharging was maintained at about 98%. When the amount of added graphene exceeded 10%, the performance gradually decreased as the amount of addition increased. The addition of graphene reduced the charge-discharge specific capacity but increased the cycling stability of the silicon.