钠离子电池负极用高性能沥青基富硫炭材料

High performance sulphur-doped pitch-based carbon materials as anode materials for sodium-ion batteries

  • 摘要: 以中温煤沥青为碳源,升华硫为硫源,经低温和高温两步热处理,成功制备了具有较高硫含量的硫掺杂沥青基炭材料。探究了炭化温度对材料组成、结构及电化学性能的影响。结果表明,随着炭化温度的升高,材料中硫含量明显减少;硫流失的同时,带来炭结构的变化,材料的比表面积和层间距逐渐增大。其中800℃炭化的材料(SC-800)硫含量达到20.19 wt.%,层间距为0.368 nm,在0.1 A/g的电流密度下,储钠首次可逆容量高达482.8 mAh/g;在0.5 A/g和5 A/g的电流密度下,循环500圈和1 000圈后,仍然保持245.9和103.7 mAh/g的比容量。SC-800优异的电化学性能归因于高硫含量、较大的层间距和合适的孔道结构。

     

    Abstract: Sulfur-doped pitch-based carbon materials with a high sulfur content were prepared by a two-step heat treatment method using medium-temperature coal tar pitch as the carbon source and sublimated sulfur as the sulfur source. The effect of the final carbonization temperature on the composition, microstructure and electrochemical properties of the materials suitability as anode materials for sodium ion batteries were investigated. Results show that by increasing the final carbonization temperature the sulfur content of the materials decreases significantly, and the specific surface area and interlayer spacing gradually increase. Among the carbons obtained at different final carbonization temperatures, the sulfur content of the carbon at 800℃ was 20.19 wt.% and its interlayer spacing 0.368 nm, and its reversible capacity was 482.8 mAh/g at 0.1 A/g for the first cycle and had values of 245.9 and 103.7 mAh/g at 0.5 and 5 A/g, respectively after 500 cycles. The excellent sodium storage performance of the carbon at 800℃ is attributed to its high sulfur content, large interlayer spacing and suitable pore structure.

     

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