本文關(guān)鍵詞： 石墨烯 六溴苯 鋰離子電池 金屬硫化物 負(fù)極材料　出處：《天津大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：鋰離子電池具有電壓高、容量大、循環(huán)壽命長(zhǎng)等優(yōu)點(diǎn),而被廣泛應(yīng)用于手機(jī)、筆記本等便攜式電子設(shè)備領(lǐng)域,并被認(rèn)為是最具應(yīng)用前景的能源存儲(chǔ)裝置。為了進(jìn)一步提高鋰離子電池的能量密度和循環(huán)壽命,需要進(jìn)一步開(kāi)發(fā)新的負(fù)極材料。石墨烯作為碳家族一員,由于具有獨(dú)特的二維結(jié)構(gòu)、較高的比表面積和優(yōu)異的電子傳導(dǎo)速度,而成為最具潛力的鋰離子電池負(fù)極材料�；诖�,本文探索了不同的方法制備石墨烯,并將其用作為鋰離子電池負(fù)極材料。此外,還制備了石墨烯/MoS2復(fù)合材料,研究了其電化學(xué)性能。具體研究結(jié)果如下:1.以溴化亞銅為還原劑,在不同溶劑中還原氧化石墨制備的石墨烯。結(jié)果表明在鹽酸的水溶劑中合成的石墨烯性能最好,通過(guò)TEM分析發(fā)現(xiàn),合成石墨烯的層數(shù)為兩層。電化學(xué)測(cè)試結(jié)果表明,在100 mA·g-1電流密度下,石墨烯的可逆放電比容量為1513 mAh·g-1,循環(huán)30次后容量還能保持在1207 mAh·g-1,容量保持率為80%。增加電流密度至500 m A·g-1時(shí),可逆容量還能夠達(dá)到981 mAh·g-1,遠(yuǎn)高于石墨烯的理論比容量。2.采用Ullmann反應(yīng),以六溴苯為原料,溴化亞銅為催化劑,分別在無(wú)水無(wú)氧和空氣氣氛下,探索了合成石墨烯的最佳條件。結(jié)果表明,無(wú)水無(wú)氧條件下,六溴苯的加入量0.04 g,反應(yīng)溫度為140℃,反應(yīng)時(shí)間為12 h時(shí),合成的石墨烯質(zhì)量最佳。在此條件下,空氣氛圍中,也可生成高質(zhì)量的石墨烯。3.采用Ullmann反應(yīng),以銅片為基底和催化劑,在Ar氣氛圍中回流1.5 h、4h、8 h、12 h、16 h、24 h制備石墨烯。結(jié)果證明反應(yīng)16 h時(shí),制備的石墨烯質(zhì)量最優(yōu)為單層,通過(guò)差量法計(jì)算生成石墨烯的質(zhì)量為0.1 mg,以此質(zhì)量為活性物質(zhì)質(zhì)量則測(cè)得不的石墨烯的最高比容量為855.6 mAh·g-1。4.采用電化學(xué)方法,以六溴苯的原料,分別以泡沫銅和泡沫鎳為極片,在100mA·g-1的電流密度下充放電制備石墨烯。結(jié)果表明,無(wú)論是以泡沫銅還是泡沫鎳為極片充放電400次后,發(fā)現(xiàn)均有石墨烯生成,且具有一定的儲(chǔ)鋰性能。5.采用水熱法制備了不同MoS2含量的石墨烯/MoS2復(fù)合材料,其中加入鉬酸銨的量分別為0.15 g、0.20 g、0.25 g和0.30 g,并考察了12 h、24 h和36 h不同水熱時(shí)間對(duì)反應(yīng)的影響。結(jié)果表明,加入鉬酸銨0.25 g,反應(yīng)24 h時(shí),復(fù)合材料的形貌和電化學(xué)性能最好。在100 mA·g-1電流密度下,復(fù)合材料的首次放電比容量為1680.9 mAh·g-1,經(jīng)五十次循環(huán)后,容量還高達(dá)1399.3 mAh·g-1。增加電流密度至1 A·g-1,其比容量還能保持在839.1 mAh·g-1,顯示了良好的儲(chǔ)鋰性能。
[Abstract]:Li-ion batteries have the advantages of high voltage, large capacity, long cycle life, and are widely used in the field of portable electronic devices, such as mobile phones, notebooks, etc. In order to further improve the energy density and cycle life of lithium-ion batteries, new anode materials need to be further developed. Because of its unique two-dimensional structure, high specific surface area and excellent electron conduction velocity, it has become the most promising anode material for lithium ion batteries. In addition, graphene / MoS2 composites were prepared and their electrochemical properties were studied. The results are as follows: 1. Copper bromide was used as reducing agent. Graphene was prepared by reducing graphite in different solvents. The results showed that the graphene synthesized in hydrochloric acid aqueous solvent had the best properties. By TEM analysis, it was found that the layer number of graphene synthesized was two layers. At 100mA 路g ~ (-1) current density, the specific discharge capacity of graphene is 1513 mAh 路g ~ (-1), the capacity of graphene can be maintained at 1207 mAh 路g ~ (-1) after 30 cycles, and the capacity retention rate is 80%. When the current density is increased to 500mA 路g ~ (-1), The reversible capacity can also reach 981 mAh 路g-1, which is much higher than that of graphene. 2. Using Ullmann reaction, using hexabromobenzene as raw material, cuprous bromide as catalyst, in anhydrous and anaerobic atmosphere and in air atmosphere, respectively, The optimum conditions for the synthesis of graphene were investigated. The results showed that under the condition of anhydrous and anaerobic conditions, when the amount of hexabromobenzene was 0.04 g, the reaction temperature was 140 鈩，

本文編號(hào)：1554090