电化学电容器与NiMH电池电极材料的制备及性能研究

1、电化学电容器与Ni/MH电池电极材料的制备及性能研究        【中文摘要】电化学电容器和Ni/MH电池是目前两种重要的电化学能量储存装置。电化学电容器是一种新型的储能装置,结合了物理电容器高功率及传统电池高能量密度的优点,因此,其应用领域广泛,已成为新型化学电源研究中的热门之一。与此同时,碱性可充电电池如Ni/MH电池的应用范围已从动力工具扩展到便携式电子产品和电动汽车等广泛领域内。此外,由于Ni/MH具有较高的功率和低廉的价格,因此被以为是电动汽车和混合电动汽车应用中最具远景的选择。在论文研究工作中,我们制

2、备了电化学电容器和Ni/MH电池相关的电极材料,并就目标材料的成分、结构和形貌以及它们的电化学性能等进行了具体研究。主要内容如下:1.通过溶胶-凝胶法制备了纳米二氧化锡,以此作为原料利用乳液聚合原位复正当制备了无机-有机复合材料,在这种材料中二氧化锡纳米粒子嵌进到了由聚苯胺构筑的网状结构中。采用X射线衍射(XRD)和场发射扫描电镜(FESEM)对合成的复合材料进行了物理表征。使用循环伏安法、计时电位法和交流阻抗等电化学方法系统研究了所制备的样品。制备的复合材料具有较好的电容特性,最高比电容达305.3 F g1,能量密度42.4 Wh kg1,库仑效率96%。研究结果表明在PANI/SnO2复

3、合材料中,两种成分有协同效应。2.以聚乙二醇作为结构导向剂,通过化学共沉积的方法成功制备了新型有序介孔CoxNi1x层状双氢氧化物电极材料。采用X射线衍射(XRD)和场发射扫描电镜(FESEM)对样品进行了物理表征。其组成和热稳定性通过电子能谱(EDS),红外光谱(FTIR)和热分析(TG-DTA)表征。使用循环伏安法和计时电位等电化学方法系统研究了所制备的样品,在1 A g1的电流密度下比电容可达1809 F g1,并且在10 A g1的大电流密度下循环1000周后仍能保持90.2%的初始容量。此外,并就化学组成和电容之间的关系进行了讨论。3.以聚乙二醇作为结构导向剂,通过化学共沉积的方法成

4、功制备了四种具有不同插进阴离子的相氢氧化钴(绿色或蓝色)。尽管四种样品除了阴离子不同外其它合成条件都相同,但每一种样品却呈现出独特的形貌。插进阴离子对产物的层间距、形貌和电容性能起很关键的作用。采用X射线衍射(XRD)和场发射扫描电镜(FESEM)对四种产物进行了物理表征。它们的组成和热稳定性通过红外光谱(FTIR)和热分析(TG-DTA)表征。使用循环伏安法和计时电位等电化学方法对所制备的样品进行了系统研究。插进阴离子为氯离子的样品在1 A g1的电流密度下比电容达697 F g1。而插进阴离子为硫酸根的样品具有较小的晶体尺寸和规整的蜂窝状纳米结构,这使它具有较大的比表面积,本该表现出较好的

5、电容特性,但是其表现出相对较差的比电容(420 F g1)。这一由插进阴离子导致的*现象可由氢键和静电作用力来解释。此外,还就所制备的四种样品其比电容、层间距和层间水含量等进行了具体的分析讨论。4.以聚乙二醇作为结构导向剂,通过化学沉积的方法成功制备了卷曲片状纳米-Ni(OH)2电极材料。采用X射线衍射(XRD)和场发射扫描电镜(FESEM)对目标产物进行了物理表征。它的组成和热稳定性通过红外光谱(FTIR)和热分析(TG-DTA)进行表征。使用循环伏安法和计时电位等电化学方法对所制备的样品进行了系统研究。结果显示所制备的卷曲片状纳米-Ni(OH)2电极材料具有较好的电化学性能,其容量高达27

6、4 mAh g1。5.以聚乙二醇作为结构导向剂,通过化学共沉积的方法成功制备了板状铝代-Ni(OH)2电极材料。采用X射线衍射(XRD)和场发射扫描电镜(FESEM)对终端产物进行了物理表征。XRD结果显示样品为典型的相。其组成和热稳定性通过红外光谱(FTIR)和热分析(TG-DTA)进行表征。使用循环伏安法和计时电位等电化学方法对所制备的样品进行了系统研究。实验结果显示所制备的10% Al代-Ni(OH)2电极材料在0.2C倍率下放电容量达331 mAh g1。');【Abstract】 At present, electrochemical capacitor and nickel

7、/mental hydride (Ni/MH) battery are two kinds of important energy storage equipments. Electrochemical capacitor is a new type of energy storage equipment, which combines the advantages of both dielectric capacitors that can deliver high power within a very small period and conventional rechargeable

8、batteries that have high energy densities. Therefore, electrochemical capacitors have a wide range of applications and have already become one of the research interests related to new chemical energy sources studies. At the same time, alkaline rechargeable batteries such as Ni/metal hydride (Ni/MH)

9、are widely applied to todays market covering domains ranging from power tools to portable electronics and electric vehicle. Furthermore, nickel/metal hydride (Ni/MH) batteries are considered to be one of the most promising choices for electric vehicle (EV) and hybrid electric vehicle (HEV) applicati

10、ons due to high power and low cost.In this work, we have prepared relevant electrode materials of electrochemical capacitor and nickel/mental hydride (Ni/MH) battery, and studied the electrochemical performance, structural and morphological characterizations of these nanomaterials in detail. The mai

11、n content is as follows:1. Nanostructured SnO2 was prepared by the solgel method. Aniline monomer was polymerized in the suspension of nanocrystalline SnO2 to form inorganic-organic composite materials, in which SnO2 nanoparticles were embedded within netlike polyaniline (PANI). Structural and morph

12、ological characterizations of SnO2 and PANI/SnO2 were carried out using powder X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Their electrochemical properties were also investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impeda

13、nce spectroscopy. The as-prepared composites had excellent properties in the capacitance, and its specific capacitance was up to 305.3 F g1 with a specific energy density of 42.4 Wh kg1 and a coulombic efficiency of 96%. The results indicated that the PANI/SnO2 had a synergistic effect of the comple

14、mentary properties of both components. 2. A novel nanostructured mesoporous CoxNi1x layered double hydroxides (CoxNi1x LDHs), which both Co(OH)2 and Ni(OH)2 exhibitphase, have been successfully synthesized by a chemical co-precipitation route using polyethylene glycol as the structure-directing reag

15、ent. Structural and morphological characterizations were performed using powder X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The component and thermal stability of the sample were measured by energy dispersed X-ray spectrometry (EDS), FTIR and thermal analyses, in

16、cluding thermogravimetry (TG) and differential thermal analysis (DTA). Cyclic voltammogram and galvanostatic charge-discharge testified that the CoxNi1x LDH has a specific capacitance of 1809 F g1 at a current density of 1 A g1 and remains at about 90.2% of the initial value after 1000 cycles at a c

17、urrent density of 10 A g1. The relationship between the chemical composition and capacitance is discussed.3. The four-cobalt hydroxides (green or blue) with different intercalated anions were synthesized by a chemical precipitation route in which polyethylene glycol was used as the structure-directi

18、ng reagent for application in the electrode materials of electrochemical capacitors. Every one among the four samples displays an interesting and distinctive morphology although the synthesis conditions were same except for anions. The intercalated anions have a critical effect on the basal plane sp

19、acing, morphologies and capacitive properties of the products. Structural and morphological characterizations were performed using powder X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The component and thermal stability of the sample were respectively measured by F

20、TIR and thermal analyses, including thermogravimetry (TG) and differential thermogravimetry (DTG). The electrochemical behaviors were measured by cyclic voltammogram and galvanostatic charge-discharge. The specific capacitance is up to 697 F g1 at a charge-discharge current density of 1 A g1 for the

21、 sample with intercalated chlorine. But the sample with intercalated sulfate, which has small crystalline size, more disordered structure and almost perfect alveolate nanostructure with a large su*ce area, exhibits relatively poor specific capacitance (420 F g1 ). The exceptive phenomena caused by i

22、ntercalated anions were explained by hydrogen bonding and electrostatic forces. Moreover, the relationships between the specific capacitance, basal plane spacing as well as the content of the interlayer water were discussed in detail for the four as-synthesized samples.4. A nanostructured curly lami

23、nar-nickel hydroxide was successfully synthesized by a chemical precipitation route in which polyethylene glycol was used as the structure-directing reagent. Structural and morphological characterizations were performed using powder X-ray diffraction (XRD) and field emission scanning electron micros

24、copy (FESEM). The component and thermal stability of the sample were respectively measured by FTIR and thermal analyses, including thermogravimetry (TG) and differential thermal analysis (DTA). Its electrochemical properties were evaluated by cyclic voltammetry (CV) and galvanostatic charge-discharge technique in 6 M KOH aqueous electrolyte. The results showed that the nanostructured curly laminar-Ni(OH)2 exhibits a high electrochemical capacity of up to 274 mAh g1.5. A board-like Al-substituted-Ni(OH)2 were synthesized via a optimizing chemical precipi