本文選題：五氧化二鉭　切入點(diǎn)：還原氧化石墨烯　出處：《吉林大學(xué)》2017年碩士論文

【摘要】：近階段,金屬-空氣電池的研究掀起了學(xué)術(shù)界的新浪潮,與大多數(shù)電池相比,金屬-空氣電池的陰極活性材料為氧氣,主要來(lái)源于空氣中,不存儲(chǔ)在電池內(nèi)部,在充、放電過(guò)程中被陰極表面的催化劑材料催化參與電池的相關(guān)反應(yīng)。大多數(shù)金屬-空氣電池使用的是水系電解液,如濃的氫氧化鉀溶液,但鋰-空氣電池使用的電解液更多的是非水系溶液,在電池的工作過(guò)程中不參與反應(yīng)。由于它具有最高的理論能量密度(11700 Wh/kg),鋰-空氣電池在眾多電池體系中脫穎而出,但要將其應(yīng)用到現(xiàn)實(shí)生活中還有很多挑戰(zhàn)需要我們?nèi)ッ鎸?duì),比如陰極反應(yīng)的機(jī)理、在半開(kāi)放體系中電池各組分的穩(wěn)定、容量的衰減以及循環(huán)壽命短等等。為了得到更好的電池性能,學(xué)者們不斷對(duì)研究體系進(jìn)行調(diào)整和完善,其中陰極催化劑材料的設(shè)計(jì)備受學(xué)者們的青睞。目前,主要的陰極催化劑材料有多孔碳材料(碳納米管、石墨烯等)、過(guò)渡金屬氧化物(Fe_2O_3、MnO_2、Co_3O_4等)、合金(Au-Pt/XC-72、Pt-GNS等)等。在本工作中,我們利用水熱法制備了Ta_2O_5、rGO/Ta(MeO)_5、rGO/Ta_2O_5納米催化劑材料。通過(guò)XRD、SEM和TEM等測(cè)試手段對(duì)樣品的形貌及結(jié)構(gòu)進(jìn)行了表征和分析,數(shù)據(jù)顯示,該方法制得的Ta_2O_5為正交晶系P21212(18)空間群,晶胞參數(shù)a=6.198?,b=40.29?,c=3.888?,α=β=γ=90°;樣品rGO/Ta_2O_5具有最大的比表面積和最高的還原程度,作為鋰-空氣電池的陰極催化劑可得到較好的電池性能,該樣品首次放電比容量為8300 mAh/g,相比其他幾種催化劑過(guò)電勢(shì)降低了0.4 V,循環(huán)穩(wěn)定性提高了近4倍。結(jié)合文獻(xiàn)分析,電極材料具有較大的比表面積、較高的還原程度,在電池充、放電的過(guò)程中可提供更多的反應(yīng)活性位點(diǎn),有利于提高放電產(chǎn)物的沉積量及層間Li_2O_2的生成量,從而提高電池的放電容量及降低反應(yīng)的過(guò)電勢(shì),得到較好的電池循環(huán)性能。這項(xiàng)研究表明,五氧化二鉭/還原氧化石墨烯復(fù)合催化劑材料將成為非常有前景的鋰-空氣電池陰極催化劑之一。此外,我們還制備了具有石墨烯骨架結(jié)構(gòu)的五氧化二鉭納米材料。通過(guò)XRD、SEM和TEM等測(cè)試手段對(duì)樣品進(jìn)行了表征和分析;有關(guān)鋰-空氣電池的性能測(cè)試顯示,當(dāng)電流密度為100 mA/g時(shí),首次放電比容量為2843 mAh/g,相比于普通無(wú)定形Ta_2O_5納米材料,其性能提升了30%,且具有更好的倍率性能和循環(huán)穩(wěn)定性。本論文通過(guò)探究鉭氧化物在鋰-空氣電池中的催化性能,為金屬-空氣電池的研究提供了新的研究思路與實(shí)驗(yàn)方法。
[Abstract]:In recent years, the research of metal-air battery has set off a new wave in academia. Compared with most batteries, the cathode active material of metal-air battery is oxygen, which is mainly derived from the air, not stored in the battery, but filled.In the discharge process, the catalyst materials on the cathode surface catalyze to participate in the battery reaction.Most metal-air batteries use aqueous electrolytes, such as concentrated potassium hydroxide solutions, but lithium-air batteries use more non-aqueous solutions and do not take part in the reaction.Because it has the highest theoretical energy density of 11, 700 what / kg / kg, lithium-air batteries stand out in many battery systems, but there are still many challenges to face in real life, such as the mechanism of cathodic reaction.In the semi-open system, the stability of each component, the attenuation of capacity and the short cycle life, etc.In order to obtain better battery performance, the research system has been continuously adjusted and improved, among which the design of cathode catalyst materials is favored by scholars.At present, the main cathode catalyst materials are porous carbon materials (carbon nanotubes, graphene, etc., transition metal oxides, Fe2O3MnO2CO3O4, Au-Pt / XC-72Pt-GNS and so on).In this work, we have prepared the Ta2O5R / TaMeOG / Tas / Tas / T / T _ 2O _ 5 nano-catalyst materials by hydrothermal method.The morphology and structure of the samples were characterized and analyzed by means of TEM and SEM. The data show that the Ta_2O_5 prepared by this method is an orthogonal crystal system P21212O18) space group, the unit cell parameter a6.19880.290.29cncncncncncncncncnchrc88-8, 偽 = 尾 = 緯 90 擄, the sample rGO/Ta_2O_5 has the largest specific surface area and the highest degree of reduction, and the results show that the sample rGO/Ta_2O_5 has the highest specific surface area and the highest reduction degree, and the crystal cell parameters of the sample are as follows: P2121212) space group.As a cathode catalyst for lithium-air battery, the performance of the cathode catalyst is better. The initial discharge specific capacity of the sample is 8300 mg / g, which is 0.4 V lower than that of other catalysts, and the cyclic stability is improved nearly 4 times.Combined with literature analysis, the electrode material has a large specific surface area, a higher reduction degree, and can provide more reactive sites in the process of battery charge and discharge, which is helpful to increase the deposition amount of discharge products and the production of interlaminar Li_2O_2.Thus, the discharge capacity of the battery is increased and the overpotential of the reaction is reduced, and the better cycle performance of the battery is obtained.This study shows that tantalum pentoxide / reduced graphene oxide composite catalyst materials will become one of the most promising cathode catalysts for lithium-air batteries.In addition, tantalum pentoxide nanomaterials with graphene skeleton structure were prepared.The samples were characterized and analyzed by means of XRD-SEM and TEM. The performance tests of lithium-air batteries show that the first discharge specific capacity of the lithium-air battery is 2843 mg / g when the current density is 100 mA/g, which is higher than that of the ordinary amorphous Ta_2O_5 nanomaterials.Its performance improves 30%, and has better rate performance and cycle stability.In this paper, the catalytic performance of tantalum oxide in lithium-air battery is studied, which provides a new research idea and experimental method for metal-air battery.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36;TM911.41

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