發(fā)布時(shí)間：2018-01-15 11:42

  本文關(guān)鍵詞：二氧化鈦復(fù)合材料的制備及儲(chǔ)鋰負(fù)極材料的性能研究　出處：《蘇州大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 二氧化鈦 二氧化鉬 碳納米管 鋰離子電池 超級(jí)電容器

【摘要】：過(guò)渡金屬氧化物由于其優(yōu)越的電化學(xué)性能已在鋰離子電池和超級(jí)電容方面引起了廣泛的關(guān)注。二氧化鈦是研究較早的金屬氧化物負(fù)極材料,由于結(jié)構(gòu)穩(wěn)定、循環(huán)性能優(yōu)越、價(jià)格低廉、環(huán)境友善、安全性高等特點(diǎn),成為近年來(lái)的研究熱點(diǎn)。但是Ti O2材料電子電導(dǎo)率低且鋰離子在其內(nèi)部的擴(kuò)散系數(shù)較小,因而較多的研究工作旨在合成納米尺寸的Ti O2材料,以及將Ti O2與導(dǎo)電碳材料、金屬材料、金屬氧化物材料等進(jìn)行復(fù)合,提高材料的導(dǎo)電性。本文以碳納米管為骨架,Ti O2作為中間層,無(wú)定形碳/二氧化鉬作為外層導(dǎo)電層,制備了三明治結(jié)構(gòu)的C/Mo O2@Ti O2@CNT復(fù)合材料,通過(guò)SEM、TEM、XRD等對(duì)材料進(jìn)行物理表征,并采用了循環(huán)伏安、恒流充放電、交流阻抗等方法進(jìn)行了電化學(xué)性能測(cè)試,具體內(nèi)容如下:1.通過(guò)鈦酸異丙酯水解產(chǎn)生Ti O2顆粒包覆在CNT表面,并探究了鈦酸異丙酯與CNT量的配比,最終確定1 mmol的鈦酸異丙酯和25 mg的CNT混合制備出了包覆均勻的Ti O2@CNT材料。以葡萄糖為碳源,將Ti O2@CNT材料置于0.1M的葡萄糖水溶液中,再經(jīng)過(guò)煅燒即可制備C@Ti O2@CNT復(fù)合材料,復(fù)合材料的碳層厚度約為5 nm,含量為5.26%。三明治結(jié)構(gòu)的C@Ti O2@CNT復(fù)合材料表現(xiàn)出了良好的電化學(xué)性能,在C/5的倍率下循環(huán)100次后容量仍保持在176 m Ah/g,Ti O2@CNT材料循環(huán)100次后的容量?jī)H為137 m Ah/g,且復(fù)合材料的容量保持率高,庫(kù)倫效率在98%左右。2.通過(guò)鉬酸鈉在酸性條件下的水解,在Ti O2@CNT材料表面包覆Mo O3層,再經(jīng)Ar/H2將Mo O3還原成Mo O2,制備Mo O2@Ti O2@CNT復(fù)合材料。探究了Mo O2層的厚度對(duì)復(fù)合材料的結(jié)構(gòu)的影響,最終確定0.5 mmol的鉬酸鈉與100 mg的Ti O2@CNT材料混合制備出包覆緊密、厚度均勻的Mo O2@Ti O2@CNT復(fù)合材料,Mo O2層的厚度約為10 nm,Mo O2的含量約為24.07%。Mo O2@Ti O2@CNT復(fù)合材料在C/5倍率下循環(huán)100次后容量為253 m Ah/g,且容量損失僅有9.6%,庫(kù)倫效率約為98%,在30C的高倍率下進(jìn)行5000次的充放電,仍能保持60 m Ah/g的容量,表現(xiàn)出了復(fù)合材料優(yōu)越的電化學(xué)性能。3.采用恒流充放電、循環(huán)伏安等方法測(cè)試了Mo O2@Ti O2@CNT復(fù)合材料、活性炭材料水系Na2SO4電解液電容性能,并測(cè)試了AC/Mo O2@Ti O2@CNT鈉離子混合超級(jí)電容器的電化學(xué)性能。以飽和甘汞電極為參比電極,Pt為對(duì)電極,復(fù)合材料為工作電極,考察了Mo O2@Ti O2@CNT復(fù)合材料在1M的Na2SO4溶液中的電容性能,首次循環(huán)時(shí)比電容119.3 F/g,循環(huán)2000次后比電容為83.5 F/g,容量保持率為70%,表現(xiàn)出了良好的循環(huán)穩(wěn)定性。同樣采用三電極體系測(cè)試了AC在1M的Na2SO4溶液中的電容性能,在相同電流密度下,Mo O2@Ti O2@CNT材料的比電容是AC的1.6~1.8倍。因而實(shí)驗(yàn)選取了AC:Mo O2@Ti O2@CNT質(zhì)量比為2:1制作正、負(fù)極極片,組裝成電容器�；旌想娙萜髟�200 m A/g的電流密度下測(cè)試循環(huán)性能,首次放電電容為101F/g,經(jīng)過(guò)2500次的循環(huán)之后,電容器的容量為73 F/g,容量保持率為72.3%,顯示了良好的循環(huán)穩(wěn)定性,同時(shí),混合電容器還具有較好的倍率性能。
[Abstract]:Transition metal oxides due to its excellent electrochemical performance has attracted wide attention in the lithium ion battery and super capacitor. Titanium dioxide is of metal oxide anode materials earlier, due to the structural stability, superior cycle performance, low cost, environment friendly, high security features, has become the research hotspot in recent years. But the Ti O2 material the low electronic conductivity and lithium ion diffusion coefficient in the interior of the small Ti O2 material so a lot of research work aimed at synthesizing nanometer size, and the Ti and O2 conductive carbon materials, metal materials, metal oxide materials such as composite, improve the conductivity of the material. In this paper, using carbon nanotubes as framework, Ti as the middle O2 the two layer, the amorphous carbon / molybdenum oxide as the outer conductive layer, the preparation of C/Mo O2@Ti O2@CNT composite sandwich structure by SEM, TEM, XRD etc. to the physical materials Characterization and using cyclic voltammetry, galvanostatic charge discharge and AC impedance methods such as electrochemical performance test, the specific content is as follows: 1. by isopropyl titanate hydrolysis to produce Ti O2 particles coated on the surface of CNT, and to explore the isopropyl titanate and CNT CNT mixed ratio of isopropyl titanate to finalize the 1 mmol and 25 mg to prepare Ti O2@CNT material evenly coated. Using glucose as carbon source, glucose water solution Ti O2@CNT material in 0.1M, and then calcined to prepare C@Ti O2@CNT composites, carbon thickness of composite material is about 5 nm, the content of C@Ti O2@CNT composite materials a good electrochemical performance of 5.26%. sandwich structure, after 100 cycles the capacity remained at 176 m Ah/g in C/5, Ti O2@CNT after 100 cycles the capacity is only 137 m Ah/g, and the capacity of the composite to maintain a high rate of Kulun Efficiency is about 98%.2. by sodium molybdate under acidic conditions of hydrolysis, in Mo O3 Ti coating layer on the surface of O2@CNT material by Ar/H2 Mo O3 reduced to Mo O2, Mo O2@Ti O2@CNT composites were prepared. Influence of the structure of Mo O2 layer thickness of composite materials, and ultimately determine the Ti O2@CNT material mixed 0.5 mmol sodium molybdate and 100 mg prepared by coating Mo O2@Ti O2@CNT composite compact, uniform thickness, Mo thickness of the O2 layer is about 10 nm, the content of Mo O2 is about 24.07%.Mo O2@Ti O2@CNT composite at C/5 rate after 100 cycles the capacity is 253 m Ah/g, and the capacity loss only 9.6%, Kulun efficiency is about 98% and 5000 times of charge and discharge at high rate of 30C, still can maintain 60 m capacity of Ah/g showed excellent electrochemical performance of.3. composite materials by galvanostatic charge discharge, cyclic voltammetry test method Mo O2@Ti O2@CNT composite material The material, activated carbon material for aqueous Na2SO4 electrolyte capacitor properties, electrochemical properties of AC/Mo O2@Ti O2@CNT sodium ion hybrid supercapacitors were tested. The saturated calomel electrode as reference electrode, Pt composite as electrode as the working electrode, the effects of Mo O2@Ti O2@CNT composite material of capacitor performance in Na2SO4 in 1M solution for the first time, cycle specific capacitance of 119.3 F/g, after 2000 cycles, the specific capacitance is 83.5 F/g, the capacity retention rate was 70%, showing a good cycling stability. Using the same three electrode system in the AC Na2SO4 1M solution in the capacitive test, at the same current density, Mo O2@Ti ratio of O2@CNT materials the capacitance is 1.6~1.8 times of AC. Thus the experiment selected AC:Mo O2@Ti O2@CNT mass ratio of 2:1 is made, the negative pole piece, assembling capacitor. The hybrid capacitor test cycle performance at a current density of 200 m A/g, the first discharge capacity For 101F/g, after 2500 cycles, the capacity of the capacitor is 73 F/g, and the capacity holding rate is 72.3%. It shows good cycling stability. At the same time, the hybrid capacitor has good rate performance.

【學(xué)位授予單位】：蘇州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ134.11;TB33

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

1 孟慶函,劉玲,宋懷河,凌立成;炭氣凝膠為電極的超級(jí)電容器的研究[J];功能材料;2004年04期

2 孫現(xiàn)眾;張熊;張大成;馬衍偉;;活性炭基Li_2SO_4水系電解液超級(jí)電容器[J];物理化學(xué)學(xué)報(bào);2012年02期

3 劉亞菲;胡中華;任煉文;楊靜;陳曉妹;;高性能活性炭電極材料在雙電層電容器中的應(yīng)用[J];新型炭材料;2007年04期

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本文編號(hào)：1428181