Preparation of PTFE/Ketjen Black-C flexible composites by high energy ball milling method and its electrochemical application
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摘要: 对荷叶进行多阶温度炭化得到前驱炭材料,将材料与科琴黑(KB)、聚四氟乙烯(PTFE)按照2:2:3的质量比球磨混合后真空抽滤制备一种锂硫电池中间层柔性材料,PTFE/KB-C复合材料的多孔结构能为高阶硫化物Li2Sn(4≤n≤8)的进一步还原提供较多的三相反应位点,并利用PTFE/KB-C复合材料良好的多层多孔化学吸附作用来抑制可溶性多硫化物的穿梭。该中间层在以纯硫材料为正极的锂硫电池电性能测试表征中,1.0 C(电流密度1 675 mA·g-1)倍率下首次放电比容量达1 350 mAh·g-1,没有硝酸锂添加剂条件下经过100次充放电循环后比容量依旧保持在960 mAh·g-1,库伦效率基本在95%以上,保持了良好的循环稳定性。Abstract: A lithium-sulfur battery interlayer flexible material composed of precursor carbon material was prepared by multi-step temperature carbonization process with lotus-leaf as the raw material, ball-milling blending and vacuum filtrating precursor carbon material, Ketjen Black (KB) as well as polytetrafluo-roethylene(PTFE) at the mass ratio of 2:2:3. The porous structure of PTFE/KB-C composites can not only provide a large number of three-phase reaction sites for further reduction of higher-order sulfide Li2Sn (4≤n≤8), but also suppress the shuttle effect of soluble polysulphide by good multilayer porous chemical adsorption effect of PTFE/KB-C composites. The lithium-sulfur battery capacity property test characterization of interlayer with pure sulfur as the anode material shows that initial discharge specific capacity is as high as 1 350 mAh·g-1 at 1.0 C rate (current density is 1 675 mA·g-1) and remains 960 mAh·g-1 after 100 charge-discharge cycles without nitric acid lithium additives. Coulomb efficiency above 95% is achieved, demonstrating high performance of cycle stability.
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Key words:
- lithium-sulfur battery /
- interlayer /
- anode /
- shuttle effect /
- lotus-leaf
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