无黏结剂柔性Si/CNT/纤维素复合阳极及其电化学性能

硅/碳复合材料作为最具潜力的下一代阳极材料,受到广泛关注。为减少硅巨大膨胀所产生的应力,避免硅纳米颗粒的粉化,提高硅基锂离子电池的电化学性能,制备了一种多微孔结构的多壁碳纳米管(MWCNTs)纸,嵌入纳米硅制得Si/MWCNTs/纤维素复合柔性锂离子电池阳极。FESEM显示,纳米硅均匀地嵌入在MWCNTs构建的三维导电网络中,纳米硅和导电载体具有良好的接触,使得界面电阻大幅下降,同时纳米硅在电池充放电过程中具有足够的膨胀空间,保证了材料的结构稳定性和化学稳定性。电化学检测显示,其首次放电比容量达到2024 mAh/g,循环30次后比容量维持在850 mAh/g,展示出良好的循环稳定性和较高的比容量。同时,其制作工艺相比传统涂敷类阳极得以简化,可操作性高,易于实现产业化。

Flexible Si/carbon nanotubes/cellulose composite anodes without adhesive and its electrochemical properties

Silicon/carbon composite materials were widely considered as the next generation and the most potential anode materials. In order to reduce the huge expansion of silicon, avoid silicon nanoparticle powder and improve the electrochemical performance of silicon based lithium ion battery, a microporous structure paper of multiwalled carbon nanotubes(MWCNTs) was prepared, and the Si/MWCNTs/cellulose composite flexible lithium ion battery anode was prepared by embedding nanoscale silicon. FESEM shows that the nano-silicons are evenly inserted in the three-dimensional conductive network constructed by MWCNTs. This results in decreased interface resistance owing to increasing contact area between silicon and MWCNTs. The high hole of the anode provides enough space for expansion of silicon in cycles. So, the structural stability and chemical stability of the electrodes significantly are guaranteed. Electrochemical tests demonstrate that the first discharge capacity reaches 2024 mAh/g, and the capacity is still maintained at 850 mAh/g after 30 cycles, which shows good cyclic stability and high specific capacity. The unique electrodes show excellent electrochemical performance. The fabrication process of the electrode is much simpler than traditional coating process, strong maneuverability and a satisfactory prospect for industrial applications.