本文選題：超級活性炭 + 結(jié)構(gòu)　； 參考：《華東理工大學(xué)》2017年碩士論文

【摘要】：超級活性炭具有巨大的比表面積、孔徑分布相對集中、低灰份和良好的導(dǎo)電性等特點(diǎn),在電化學(xué)儲能領(lǐng)域具有廣泛的應(yīng)用前景。堿法活化,特別是KOH活化石油焦是目前常用的制備超級活性炭方法,但其工業(yè)化制備仍存在諸多產(chǎn)品質(zhì)量問題。在前期攻克KOH活化過程中反應(yīng)器內(nèi)部傳質(zhì)優(yōu)化技術(shù)、金屬鉀的安全處理技術(shù)、低灰份控制技術(shù)、粒徑控制技術(shù)、表面處理技術(shù)基礎(chǔ)上,我們成功制備出30噸/年規(guī)模超級活性炭產(chǎn)品。本文以此材料為主要原料,分析了其物化結(jié)構(gòu),對比了其與商業(yè)電容活性炭的物性差異,考察了其在超級電容器及Li-S電池正極中的電化學(xué)應(yīng)用性能,得到結(jié)論如下:(1)以石油焦為原料、KOH為活化劑,噸級規(guī)模制備出超級活性炭粗品,進(jìn)一步通過灰份控制、粒徑控制、表面后處理技術(shù),得到超級活性炭產(chǎn)品(SAC)。其主要性能指標(biāo)如下:平均粒徑～5 μm,振實(shí)密度0.35 g/cm3,電導(dǎo)率4 S/cm,比表面2000 m2/g,平均孔徑1-3 nm,灰分0.07 wt%,氧含量2 wt%。與商業(yè)化電容活性炭相比,所制SAC具有最高的比表面積、最低的灰分和氧含量、相對集中的粒徑分布。(2)當(dāng)用于超級電容器電極材料時,在Et_4NBF_4/PC體系,SAC的比容量在0.5 A/g時為122 F/g,在10 A/g時的比容量是104.6 F/g,僅下降了 14%,循環(huán)5000次后容量保持率為94.5%,性能優(yōu)于目前商業(yè)電容活性炭。進(jìn)一步對比了 SAC在SBPBF4/PC和Et4NBF4/PC電解液體系中的電化學(xué)行為。由于SBP+具有較小的離子半徑,SAC在SBPBF4/PC中的比容量比在Et4NBF4/PC中高10%,且正負(fù)極容量對稱性更佳,5000次循環(huán)容量保持率為96.2%。(3)探討了 SAC在高性能Li-S電池正極材料中的應(yīng)用潛力。首先以SAC為單質(zhì)硫載體材料,采用熔融浸漬法得到SAC/S復(fù)合材料。由于SAC豐富的微孔結(jié)構(gòu)可以對多硫離子產(chǎn)生較強(qiáng)的限域作用,SAC/S在0.5C時的首次放電比容量為870mAhg~(-1),經(jīng)過300次循環(huán),容量保持率為67%。其次以SAC作為功能性涂層,直接涂覆在硫電極或商業(yè)化隔膜的表面來抑制長鏈聚硫化物向負(fù)極的穿梭。正極涂覆和隔膜涂覆都能顯著提升鋰硫電池的放電容量和循環(huán)穩(wěn)定性。但是正極涂覆層在循環(huán)過程中有可能因?yàn)殡姌O體積變化而破裂,失去保護(hù)作用,相比之下,隔膜涂覆層則能保持較好的穩(wěn)定性。當(dāng)使用隔膜涂覆層,硫正極在0.5 C時的首次放電容量為1320 mAh g~(-1),經(jīng)過100次循環(huán)后,可逆容量為997 mAh g~(-1),容量保持率為76%,在3 C時仍能獲得673 mAh g~(-1)的可逆容量。
[Abstract]:Super activated carbon has the characteristics of large specific surface area, relatively concentrated pore size distribution, low ash content and good electrical conductivity, etc. It has a wide application prospect in the field of electrochemical energy storage. Alkaline activated petroleum coke, especially KOH activated petroleum coke, is a commonly used method to prepare superactivated carbon. However, there are still many problems in the industrial preparation of petroleum coke. On the basis of mass transfer optimization technology in reactor, safety treatment technology of potassium metal, low ash content control technology, particle size control technology and surface treatment technology in the early stage of KOH activation, We successfully prepared 30 tons / year scale super-activated carbon products. In this paper, the physical and chemical structure of this material was analyzed, the physical properties of the material were compared with commercial capacitor activated carbon, and the electrochemical application performance of the material in supercapacitor and Li-S battery positive electrode was investigated. The conclusion is as follows: (1) Super-activated carbon was prepared by using petroleum coke as raw material Koh as activator and tonnage scale. Further, through ash control, particle size control and surface post-treatment technology, the super activated carbon product was obtained. The main performance parameters are as follows: average particle size is 5 渭 m, vibrational density is 0.35 g / cm ~ 3, conductivity is 4 S / cm, specific surface is 2000 m ~ 2 / g, average pore size is 1-3 nm, ash content is 0.07 wt, oxygen content is 2 wt. Compared with commercial capacitive activated carbon, the SAC has the highest specific surface area, the lowest ash and oxygen content, and the relatively concentrated particle size distribution. The specific capacity of Et_4NBF_4/PC is 122F / g at 0.5 Ag and 104.6 Fr / g at 10A / g, which is only 14 times lower. After 5000 cycles, the capacity retention rate is 94.5%, which is superior to the current commercial capacitive activated carbon. The electrochemical behavior of SAC in SBPBF4/PC and Et4NBF4/PC electrolytes was further compared. Due to the fact that the specific capacity of SBP in SBPBF4/PC is 10% higher than that in Et4NBF4/PC, and the positive and negative electrode capacity symmetry is better than that in Et4NBF4/PC, the capacity retention rate of 5000th cycle is 96. 2%. The potential application of SAC in the cathode material of high performance Li-S battery is discussed. Firstly, SAC/S composites were prepared by melt impregnation with SAC as the carrier of sulfur. The initial discharge specific capacity of SAC / S at 0.5 C is 870 mg / g ~ (-1) because the rich micropore structure of SAC can have a strong limiting effect on polysulfide ions. After 300 cycles, the capacity retention rate is 6770 m 路g ~ (-1) 路L ~ (-1) 路L ~ (-1) 路L ~ (-1) 路L ~ (-1) 路L ~ (-1). Secondly, SAC was used as the functional coating, which was directly coated on the surface of sulfur electrode or commercial diaphragm to inhibit the shuttle from long chain polysulfide to negative electrode. Both positive electrode coating and diaphragm coating can significantly improve the discharge capacity and cycle stability of lithium-sulfur batteries. However, the positive electrode coating may break down due to the change of electrode volume during the cycling process, and lose its protective effect. In contrast, the diaphragm coating can maintain better stability. When the membrane is coated, the initial discharge capacity of the sulfur positive electrode is 1320 mAh / g ~ (-1) at 0. 5C. After 100 cycles, the reversible capacity is 997 mAh / g ~ (-1) and the capacity retention is 76 ~ (-1), and the reversible capacity of 673 mAh / g ~ (-1) can be obtained at 3 C.
【學(xué)位授予單位】：華東理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ424.1

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