磺酰氯促进金属氯化物插层石墨以实现高效钠存储

Sulfonyl chloride-intensified metal chloride intercalation of graphite for efficient sodium storage

  • 摘要: 金属氯化物-石墨插层化合物具有导电性优异,石墨层间距大等特点,可用作钠离子电池负极材料。然而,在传统金属氯化物插层石墨过程中,不可避免地用到氯气,既增加了实验操作的风险,也对实验设备提出更高要求。基于上述原因,本文创新性地使用SO2Cl2作为氯源来促进BiCl3插层石墨。该方法不仅有效提高了BiCl3插层效率,也避免了直接使用氯气带来的安全性风险。采用该方法所合成的三氯化铋-石墨插层化合物(BiCl3-GICs)的层间距为1.26 nm,BiCl3插层含量高达42%。以其为负极材料,组装的钠离子电池具有高的比容量(213 mAh g1 at 1 A g1)和优异的倍率性能(170 mAh g1 at 5 A g1)。此外,原位拉曼光谱测试结果表明,首圈放电后石墨与插层的BiCl3相互作用减弱,该过程有效促进了钠离子在石墨层内的存储。采用该方法可成功制备多种类型金属氯化物-石墨插层化合物,为开发高性能储能材料提供了可行思路。

     

    Abstract: Metal chloride-intercalated graphite with excellent conductivity and a large interlayer spacing is highly desired for use in sodium ion batteries. However, halogen vapor is usually indispensable in initiating the intercalation process, which makes equipment design and experiments challenging. In this work, SO2Cl2 was used as a chlorine generator to intensify the intercalation of BiCl3 into graphite (BiCl3-GICs), which avoided the potential risks, such as Cl2 leakage, in traditional methods. The operational efficiency in the experiment was also improved. After the reaction of SO2Cl2, BiCl3, and graphite at 200 °C for 20 h, the synthesized BiCl3-GICs had a large interlayer spacing (1.26 nm) and a high amount of BiCl3 intercalation (42%), which gave SIBs a high specific capacity of 213 mAh g1 at 1 A g1 and an excellent rate performance (170 mAh g1 at 5 A g1). In-situ Raman spectra revealed that the electronic interaction between graphite and intercalated BiCl3 is weakened during the first discharge, which is favorable for sodium storage. This work broadly enables the increased intercalation of other metal chloride-intercalated graphites, offering possibilities for developing advanced energy storage devices.

     

/

返回文章
返回