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

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SO_(2)Cl_(2)作为氯源来促进BiCl_(3)插层石墨。该方法不仅有效提高了BiCl_(3)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(BiCl_(3)-GICs)的层间距为1.26 nm,BiCl_(3)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 g^(-1)at 1 A g^(-1))和优异的倍率性能(170 mAh g^(-1)at 5 A g^(-1))。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BiCl_(3)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。

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 equip-ment design and experiments challenging.In this work,SO_(2)Cl_(2)was used as a chlorine generator to intensify the intercalation of BiCl_(3)into graphite(BiCl_(3)-GICs),which avoided the potential risks,such as Cl_(2)leakage,in traditional methods.The operational efficiency in the experiment was also improved.After the reaction of SO_(2)Cl_(2),BiCl_(3),and graphite at 200℃for 20 h,the synthesized BiCl_(3)-GICs had a large interlayer spacing(1.26 nm)and a high amount of BiCl_(3)intercalation(42%),which gave SIBs a high specific capacity of 213 mAh g^(-1)at 1 A g^(-1)and an excellent rate performance(170 mAh g^(-1)at 5 A g^(-1)).In-situ Raman spectra revealed that the electron-ic interaction between graphite and intercalated BiCl_(3)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 develop-ing advanced energy storage devices.