鈷基硫化物電極材料的制備及其電化學(xué)性能研究
發(fā)布時(shí)間：2019-02-15 14:40
【摘要】：超級(jí)電容器是一種能夠?qū)崿F(xiàn)化學(xué)能和電能之間相互轉(zhuǎn)換的新型儲(chǔ)能裝置。與傳統(tǒng)的電容器和二次電池相比較,表現(xiàn)出一些優(yōu)異的性能,如:功率密度高、充放電速率快、環(huán)境友好等。對(duì)于超級(jí)電容器,其核心部分是電極材料,它的好壞直接決定其性能優(yōu)劣。因此,制備具有電化學(xué)性能優(yōu)異的電極材料仍然是超級(jí)電容器在儲(chǔ)能領(lǐng)域面臨的挑戰(zhàn)之一。本論文通過(guò)分析影響超級(jí)電容器電極材料性能的因素,構(gòu)造具有多孔結(jié)構(gòu)的鈷基硫化物納米材料,并展開(kāi)優(yōu)化以提高其電化學(xué)性能。論文工作主要包括以下幾部分:1.采用離子交換水熱法,制備了具有良好的導(dǎo)電率、暢通的離子擴(kuò)散通道以及豐富的化學(xué)反應(yīng)活性位點(diǎn)的介孔鈷基硫化物材料。通過(guò)調(diào)控原料的比例以及溶劑種類(lèi),實(shí)現(xiàn)對(duì)其電化學(xué)性能的提高,優(yōu)選出電化學(xué)性能較好的鈷基硫化物材料和氮摻雜的石墨烯氣凝膠,分別作為非對(duì)稱(chēng)超級(jí)電容器的正極和負(fù)極材料,組裝混合型非對(duì)稱(chēng)器件,考察其綜合電化學(xué)性能。2.將天然埃洛石納米管(HL)作為模板劑,采用水熱法制備了四硫代鈷酸鎳-埃洛石納米管復(fù)合材料(NiCo_2S_4-HL)。在三電極體系下測(cè)試電化學(xué)性能,數(shù)據(jù)表明:在1Ag~(-1)時(shí)比容量達(dá)589Cg~(-1),并且循環(huán)1000圈后,仍保持初始比容量的83.6%,表現(xiàn)出良好的循環(huán)穩(wěn)定性。通過(guò)在體系中引入HL,使得NiCo_2S_4與HL通過(guò)自組裝形成多孔花狀結(jié)構(gòu),從而助力電化學(xué)過(guò)程的展開(kāi),并最終改善提高整體電化學(xué)性能。3.以硝酸銅和氯化鈷為原料,六次亞甲基四胺(HMT)作為沉淀劑,采用低溫水熱制備CuCo-LDH(銅鈷前驅(qū)體)的納米顆粒,前驅(qū)體分別經(jīng)過(guò)高溫煅燒和硫化得到產(chǎn)物CuCo_2O_4和CuCo_2S_4,并且對(duì)二者進(jìn)行電化學(xué)性能測(cè)試。數(shù)據(jù)表明CuCo_2S_4納米顆粒具有良好的倍率特性和循環(huán)穩(wěn)定性。這是由于Cu-Co硫化物中硫的禁帶寬度比氧的低,與對(duì)應(yīng)的氧化物相比Cu-Co硫化物的電導(dǎo)率更高、活性位點(diǎn)更多,有效地加快了氧化還原的進(jìn)行,從而改善材料綜合電化學(xué)行為。4.分別以乙二醇和丙三醇為溶劑,硫脲和氨基硫脲為硫源,用“一鍋法”合成四種不同形貌的銅鈷硫化物,并且對(duì)四種不同形貌的樣品進(jìn)行物相表征和電化學(xué)性能測(cè)試。結(jié)果表明,以丙三醇為溶劑,氨基硫脲為硫源合成的Co_2CuS_4納米顆粒,在1Ag~(-1)時(shí),比容量達(dá)到126Cg~(-1)。
[Abstract]:Supercapacitor is a new energy storage device which can convert chemical energy and electric energy. Compared with conventional capacitors and secondary batteries, it has some excellent performances, such as high power density, high charge / discharge rate and environmental friendliness. For supercapacitors, the core part is electrode material, which directly determines the performance of supercapacitors. Therefore, the preparation of electrode materials with excellent electrochemical properties is still one of the challenges in the field of energy storage for supercapacitors. In this paper, through analyzing the factors affecting the performance of electrode materials for supercapacitors, cobalt based sulfide nanomaterials with porous structure were constructed and optimized to improve their electrochemical performance. The work of the thesis mainly includes the following parts: 1. Mesoporous cobalt-based sulfide materials with good conductivity, unblocked ion diffusion channels and abundant chemical active sites were prepared by ion exchange hydrothermal method. By adjusting the proportion of raw materials and the kinds of solvents, the electrochemical properties of cobalt based sulphide materials and nitrogen-doped graphene aerogels were selected. As positive and negative electrode materials of asymmetric supercapacitors, hybrid asymmetric devices were assembled, and their comprehensive electrochemical properties were investigated. 2. The nickel thiobalate (NiCo_2S_4-HL) nanotube composites (NiCo_2S_4-HL) were prepared by hydrothermal method using natural Ellowite nanotubes (HL) as template. The electrochemical performance was measured in a three-electrode system. The results show that the specific capacity of 589 Cg-1 is 589 Cg-1 at 1Ag-1, and the initial specific capacity remains 83.6% of the initial specific capacity after 1000 cycles, showing good cyclic stability. By introducing HL, into the system, NiCo_2S_4 and HL were self-assembled to form a porous flower-like structure, which facilitated the development of electrochemical process and improved the electrochemical performance of the whole system. The nanocrystalline CuCo-LDH (copper-cobalt precursor) was prepared by using copper nitrate and cobalt chloride as raw materials and hexa-methylene tetramine (HMT) as precipitant. The precursor was calcined and vulcanized at high temperature to obtain CuCo_2O_4 and CuCo_2S_4,. The data show that CuCo_2S_4 nanoparticles have good rate characteristics and cycle stability. This is due to the fact that the band gap of sulfur in Cu-Co sulphide is lower than that of oxygen. Compared with the corresponding oxides, Cu-Co sulfide has higher conductivity and more active sites, which effectively speeds up the redox process. In order to improve the comprehensive electrochemical behavior of materials. 4. Four copper-cobalt sulfides with different morphologies were synthesized by one-pot method with ethylene glycol and glycerol as solvents and thiourea and thiosemicarbazone as sulfur source. The results showed that the specific capacity of Co_2CuS_4 nanoparticles synthesized with glycerol as solvent and thiosemicarbazone as sulfur source was 126Cg-1 at 1Ag-1.
【學(xué)位授予單位】：新疆大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TB383.1;TM53
[Abstract]:Supercapacitor is a new energy storage device which can convert chemical energy and electric energy. Compared with conventional capacitors and secondary batteries, it has some excellent performances, such as high power density, high charge / discharge rate and environmental friendliness. For supercapacitors, the core part is electrode material, which directly determines the performance of supercapacitors. Therefore, the preparation of electrode materials with excellent electrochemical properties is still one of the challenges in the field of energy storage for supercapacitors. In this paper, through analyzing the factors affecting the performance of electrode materials for supercapacitors, cobalt based sulfide nanomaterials with porous structure were constructed and optimized to improve their electrochemical performance. The work of the thesis mainly includes the following parts: 1. Mesoporous cobalt-based sulfide materials with good conductivity, unblocked ion diffusion channels and abundant chemical active sites were prepared by ion exchange hydrothermal method. By adjusting the proportion of raw materials and the kinds of solvents, the electrochemical properties of cobalt based sulphide materials and nitrogen-doped graphene aerogels were selected. As positive and negative electrode materials of asymmetric supercapacitors, hybrid asymmetric devices were assembled, and their comprehensive electrochemical properties were investigated. 2. The nickel thiobalate (NiCo_2S_4-HL) nanotube composites (NiCo_2S_4-HL) were prepared by hydrothermal method using natural Ellowite nanotubes (HL) as template. The electrochemical performance was measured in a three-electrode system. The results show that the specific capacity of 589 Cg-1 is 589 Cg-1 at 1Ag-1, and the initial specific capacity remains 83.6% of the initial specific capacity after 1000 cycles, showing good cyclic stability. By introducing HL, into the system, NiCo_2S_4 and HL were self-assembled to form a porous flower-like structure, which facilitated the development of electrochemical process and improved the electrochemical performance of the whole system. The nanocrystalline CuCo-LDH (copper-cobalt precursor) was prepared by using copper nitrate and cobalt chloride as raw materials and hexa-methylene tetramine (HMT) as precipitant. The precursor was calcined and vulcanized at high temperature to obtain CuCo_2O_4 and CuCo_2S_4,. The data show that CuCo_2S_4 nanoparticles have good rate characteristics and cycle stability. This is due to the fact that the band gap of sulfur in Cu-Co sulphide is lower than that of oxygen. Compared with the corresponding oxides, Cu-Co sulfide has higher conductivity and more active sites, which effectively speeds up the redox process. In order to improve the comprehensive electrochemical behavior of materials. 4. Four copper-cobalt sulfides with different morphologies were synthesized by one-pot method with ethylene glycol and glycerol as solvents and thiourea and thiosemicarbazone as sulfur source. The results showed that the specific capacity of Co_2CuS_4 nanoparticles synthesized with glycerol as solvent and thiosemicarbazone as sulfur source was 126Cg-1 at 1Ag-1.
【學(xué)位授予單位】：新疆大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TB383.1;TM53
【參考文獻(xiàn)】
相關(guān)期刊論文 前4條
1 吳水林;朱彥武;;面向可實(shí)用超級(jí)電容器的致密化碳材料研究（英文）[J];Science China Materials;2017年01期
2 張熙悅;張昊U，
本文編號(hào)：2423459
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