本文選題：超級(jí)電容器 + 金屬鉬基化合物��； 參考：《蘭州理工大學(xué)》2017年碩士論文

【摘要】：金屬鉬基化合物因獨(dú)特的電子導(dǎo)電性、多個(gè)可用的氧化態(tài)以及由較弱的范德華力耦合特殊的幾何結(jié)構(gòu)等特點(diǎn)。基于以上優(yōu)點(diǎn),使得金屬鉬基化合物成為超級(jí)電容器的的理想電極材料。本文針對(duì)金屬鉬基化合物,利用不同制備方法,成功合成出花狀MoO_2/MoS_2復(fù)合電極材料。在此基礎(chǔ)上,利用第三主族元素電負(fù)性的不同,進(jìn)而制備并研究MoSe_2電極材料。此外,在正四價(jià)鉬化合物的研究基礎(chǔ)上,進(jìn)一步探索正六價(jià)鉬化合物的電化學(xué)性能,成功制備出取向不同的MoO_3電極材料。利用XRD、SEM、TEM、BET和Mapping等測(cè)試技術(shù)對(duì)所制備的材料的微觀結(jié)構(gòu)和形貌進(jìn)行了分析,同時(shí)用循環(huán)伏安(CV)、恒電流充放電(PT)和電化學(xué)阻抗(EIS)等技術(shù)測(cè)試其電化學(xué)性能,并針對(duì)其電化學(xué)性能與結(jié)構(gòu)的關(guān)系展開(kāi)研究。主要研究?jī)?nèi)容和結(jié)果如下:一、以鉬酸銨、九水硫化鈉、硼氫化鈉為原料,通過(guò)控制九水硫化鈉的質(zhì)量,采用簡(jiǎn)單水熱法制備MoO_2/MoS_2電極材料。通過(guò)對(duì)產(chǎn)物進(jìn)行結(jié)構(gòu)表征,當(dāng)九水硫化鈉質(zhì)量為0.75 g時(shí)所得到的MoO_2/MoS_2樣品具有特殊的花狀微球結(jié)構(gòu),這種特殊納米微球結(jié)構(gòu)有利于電解液離子的擴(kuò)散。由于具有較好的導(dǎo)電性,特殊的花狀結(jié)構(gòu)以及MoO_2和MoS_2之間儲(chǔ)能機(jī)制的協(xié)同效應(yīng),所制備的MoO_2/MoS_2電極材料具有良好的電化學(xué)性能,在5 mV s-1掃描速率下,MoO_2/MoS_2的比容量可以達(dá)到433.3 F g-1;在經(jīng)過(guò)5000次循環(huán)后,比容量保持率為84.41%,相比純的MoO_2(循環(huán)2000圈保持33.33%)和MoS_2(循環(huán)2000圈保持58.33%)具有優(yōu)異的循環(huán)穩(wěn)定性。二、以鉬酸銨、硒粉、硼氫化鈉為原料,采用簡(jiǎn)單水熱法和后續(xù)的熱處理工藝,成功合成了MoSe_2樣品,研究MoSe_2樣品的電化學(xué)性能。此外,還探究了Mo元素與處于同主族的O、S、Se化合而成的MoO_2、MoS_2及MoSe_2三中電極材料之間的電化學(xué)性能差異,進(jìn)一步研究同主族不同電負(fù)性的非金屬元素對(duì)于鉬基化合物電極材料電化學(xué)性能的影響。結(jié)果顯示所制備的MoSe_2具有獨(dú)特的雞冠花狀結(jié)構(gòu)和較高的電導(dǎo)性。電化學(xué)結(jié)果顯示其倍率性能較MoO_2和MoS_2電極材料優(yōu)異,在5 A g-1電流密度下,倍率性能可達(dá)75.6%。此外,為了探究MoSe_2的器件特性,用所制備的MoSe_2作為負(fù)極,自制活性炭(SHAC)作為負(fù)極,組裝了MoSe_2//SHAC非對(duì)稱電容器。MoSe_2//SHAC電容器在0~1.9 V的工作窗口下,電流密度為1 A g-1時(shí),比容量可達(dá)62.08 A g-1。同時(shí),能量密度可達(dá)31.1 Wh kg-1,在1 A g-1電流密度下進(jìn)行循環(huán)穩(wěn)定性測(cè)試,循環(huán)6000圈容量依舊可以保持初始容量的94%,僅僅衰減了6%。三、以鉬酸鈉為原料,去離子水為溶劑,利用硝酸調(diào)控pH并采用簡(jiǎn)單化學(xué)沉淀法制備不同取向的MoO_3,電化學(xué)測(cè)試發(fā)現(xiàn)當(dāng)硝酸濃度為5.2 mol L-1時(shí),MoO_3在(040)晶面擇優(yōu)生長(zhǎng)。同時(shí),在該條件下的MoO_3電極材料具有優(yōu)異的電化學(xué)性能,電流密度為1 A g-1時(shí)容量可達(dá)531.85 F g-1,循環(huán)3500圈后保持初始容量的96%。在此基礎(chǔ)上,用MoO_3做為負(fù)極,用分級(jí)納米多孔碳(HNC-IPNs)做為正極,構(gòu)建MoO_3//HNC-IPNs非對(duì)稱超級(jí)電容器。該電容器在0~2.0 V的電位窗口下表現(xiàn)出優(yōu)異的應(yīng)用特性,在1 A g-1電流密度下其容量最高達(dá)到54.72 F g-1。同時(shí),其能量密度和功率密度均優(yōu)于AC//AC對(duì)稱超級(jí)電容器。
[Abstract]:Metal molybdenum based compounds are characterized by unique electronic conductivity, many available oxidation states and special geometric structures coupled with weak van Edward forces. Based on the above advantages, molybdenum based compounds become ideal electrode materials for supercapacitors. In this paper, different preparation methods have been made for molybdenum based compounds. The MoO_2/MoS_2 composite electrode material was synthesized. On this basis, the MoSe_2 electrode materials were prepared and studied by the difference of the electronegativity of the third main elements. On the basis of the study of the positive tetravalent molybdenum compound, the electrochemical energy of the positive six valence molybdenum compound was further explored, and the different MoO_3 electrode materials with different orientation were successfully prepared. The microstructure and morphology of the prepared materials were analyzed by XRD, SEM, TEM, BET and Mapping. The electrochemical properties of the materials were measured by cyclic voltammetry (CV), constant current charge discharge (PT) and electrochemical impedance (EIS), and the relationship between the electrical properties and the structure of the materials was studied. The main contents and results were studied. The following are as follows: 1. MoO_2/MoS_2 electrode material was prepared by simple hydrothermal method using ammonium molybdate, sodium sodium sulfide nine and sodium borohydride to control the quality of sodium sulfide of nine water. By the structure characterization of the product, the MoO_2/ MoS_2 samples obtained by the quality of sodium sulfide of nine g have special flower like microsphere structure. The structure of rice microspheres is beneficial to the diffusion of electrolyte ions. Due to the good conductivity, special flower structure and the synergistic effect of energy storage mechanism between MoO_2 and MoS_2, the prepared MoO_2/MoS_2 electrode materials have good electrochemical performance. The specific capacity of MoO_2/MoS_2 can reach 433.3 F g-1 at the 5 mV S-1 scanning rate. After 5000 cycles, the retention rate of specific capacity was 84.41%, compared with pure MoO_2 (2000 cycles to keep 33.33%) and MoS_2 (2000 cycles to keep 58.33%) with excellent cyclic stability. Two, using ammonium molybdate, selenium powder and sodium borohydride as raw materials, MoSe_2 samples were successfully synthesized by simple hydrothermal method and subsequent heat treatment process, and MoSe_2 samples were studied. In addition, the electrochemical performance differences between the Mo elements and the MoO_2, MoS_2 and MoSe_2 three in the same main group of O, S, and Se were also investigated. The effects of the different electronegativity of the non metal elements on the electrochemical properties of the molybdenum based compound electrode materials were further investigated. MoSe_2 has unique cockscomb like structure and high conductivity. The electrochemical results show that its multiplying performance is better than that of MoO_2 and MoS_2 electrode materials. At 5 A g-1 current density, the multiplying performance can reach 75.6%.. In order to explore the device characteristics of MoSe_2, the prepared MoSe_2 is used as the negative and the self-made activated carbon (SHAC) is used as a negative electrode. Under the working window of 0~1.9 V, the MoSe_2//SHAC asymmetrical capacitor.MoSe_2//SHAC capacitor has a current density of 1 A g-1, with a specific capacity of up to 62.08 A g-1., and the energy density can reach 31.1 Wh kg-1. The cyclic stability test is carried out under the 1 A g-1 current density, and the cycle 6000 loop capacity remains 94% of the initial capacity and only attenuates. 6%. three, using sodium molybdate as raw material, deionized water as solvent, using nitric acid to regulate pH and using simple chemical precipitation method to prepare different orientations of MoO_3, the electrochemical test found that when the concentration of nitric acid is 5.2 mol L-1, MoO_3 is preferred to grow on (040) crystal surface. At the same time, the MoO_3 electrode material under this condition has excellent electrochemical properties and current density. The capacity of 1 A g-1 is up to 531.85 F g-1, and the initial capacity 96%. is kept after 3500 cycles. On this basis, MoO_3 is used as negative electrode, and the MoO_3//HNC-IPNs unsymmetrical supercapacitor is constructed with graded nano porous carbon (HNC-IPNs) as the positive pole. The capacitor exhibits excellent application characteristics under the potential window of 0~2.0 V, and is dense at 1 A g-1. Its maximum capacity is 54.72 F g-1., and its energy density and power density are better than that of AC//AC symmetric supercapacitors.
【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O646;TM53

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本文編號(hào)：2015115