河北工业大学硕士学位论文 i微纳米结构聚苯胺的制备与性能研究 摘 要 微纳米结构聚苯胺的制备与性能研究 摘 要 近年来,聚苯胺因原料易得、合成简单、环境稳定性好和电化学特性优良而成为目前导电聚合物领域的研究热点,特别是微纳米结构聚苯胺因其潜在的包括在分子导线、生物传感器、气体分离及光电子器件等领域的应用而备受人们的关注本文运用化学氧化法,以两性结构物质为掺杂剂制备出聚苯胺微纳米管,选用微观形貌不同的聚苯胺作锂二次电池正极材料,通过电池组配工艺和测试条件的变化,利用电化学工作站和充放电测试等设备考察其电化学性能并对其进行分析 考察多种工艺条件对聚苯胺电导率及微观形貌的影响并进行优化,通过实验得到高电导率的优化条件为:过硫酸铵与苯胺单体物质量比为 1.0:1;反应时间为 11h;甲基橙与苯胺的摩尔比为 0.06:1;盐酸用量与苯胺的物质量比为 1.5:1;反应温度为 0℃反应过程中快速搅拌,逐滴滴加氧化剂,反应产物依次用水、甲醇、乙醚洗涤等条件下得到产物的电导率高,微观形貌规整有序运用红外光谱(FT-IR)分析、热失重(TGA)分析、扫描电镜(SEM) 、透射电镜(TEM) 、X-射线衍射(XRD) 、紫外光谱分析(UV) 、四探针等测试手段对所得聚苯胺的结构和性能进行测试和表征,并对聚苯胺管的形成机理进行研究。
选用微观形貌不同的聚苯胺作锂二次电池正极材料,通过恒电流充放电、循环伏安、交流阻抗等手段对组装的锂二次电池的电化学性能进行测试,考察了电池制作过程中各种条件对电池性能的影响结果表明,在小电流充放电条件下,使用 20%配比的粘结剂,5%配比的炭黑,正极片的成型压力为 20MPa,正极片的厚度较薄时电池的综合性能最好, 正极材料的微观形貌对电池性能有重要影响,当正极材料具有规整有序的微观形貌时,电池的放电比容量和循环效率较高 关键词:关键词:聚苯胺,锂二次电池, 微纳米结构,电导率,微观形貌,正极材料, 电化学性能 微纳米结构聚苯胺的制备与性能研究 iiSTUDY ON PREPARATION AND PERFORMANCE OF MICRO/NANOSTRUCTURE POLYANILINE ABSTRACT Recently years, polyaniline has become a focus in conducting polymers due to its ease of preparation, remarkable processability, excellent environment stability, special electronic properties. Especially, micro/nanostructure polyaniline have received great interest because it could be potentially used in including polymeric conducting molecular wires, biosensors, gas separation, electronic devices, etc. In this article, micro/nanostructures PANI were prepared by oxidative chemical polymerization. PANI with different morphologies used as anode of lithium secondary battery. Electrochemical performance of the batteries were investigated and analyzed. The microcosmic morphologies and conductivities of polyaniline were influenced by acid concentration, oxidant concentration, methyl orange concentration and reaction temperature, time and other factors. These factors were investigated and optimized. In the condition of n(MO) : n (An)=0.06、n(HCl) : n (An)=1.5、n(APS) : n (An) =1, APS was dropped into the system, rapid stirring, the reaction temperature was 0℃, the reaction time was 11 hours, the products were washed with deionized water, methanol and ether in sequence, polyaniline with order morphology was obtained. The thermal stability,conductivities,constitutions, structures and micro morphologies were confirmed and characterized by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy images (TEM), fourier transform infrared spectra (FTIR),UV-vis spectrometry and X-ray diffraction (XRD) , respectively. The formation mechanism of polyaniline tubes were also investigated. PANI with different morphologies were used as anode of lithium secondary battery,河北工业大学硕士学位论文 iiipolyaniline electrode were investigated by means of cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge/discharge measurements. The effects of electric current, electric agent, binder, cold-molded pressure of anode pellet and thickness on the properties of batteries were discussed in detail. The influences of morphology of anode material on battery properties were studied and analyzed. Low charge/discharge electric current, thin anode pellet , 20% binder and 5% black carbon were added, cold-molded pressure with 20 MPa, anode material with order morphology which make battery show good properties. KEY WORDS: polyaniline, lithium secondary battery, micro/nanostructures, conductivity, micro morphologies, anode, electrochemical property trdrl'[+FEEA XIE tr Efr , Fn E]1}.F'l+,fi?AI, EA fr +'F]F+T, )t:,ffnfrnrlFFfiHx1F,VldX R. r,+AI +=^t|Hfrllffi Ht ^E^, A+,fifty6aarcldt4fr,^frRl+-4.8f.il14qffi A E, uF^^@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@AA t #1+H1f,+,fn m,fHH f Ht f/f.l “ xt4ia x.Ff Nf e.t1nfnr-lF lw.H Ff fi!{{{{{'ft+ ^fr+44, fr eEf + Dl nAEfrn tttrBE “ A+,fniAIFd'J'l+FBilIt*'r#.fr{f HAA+E “x T + Mj/tI ffi fx,fH H ffi tx fi! ifi ryEA ifiA T ftFlffihr{Lt+XT Lly+. IF,.f+.'ffrffi +irni,t{.V1D)Tlfl ft , +ffiHiXX m*EeElJ. ffiElJ., fff#i., x\.+ILtrX_.Htr+若掺杂进一步进行, “岛”的尺寸稍微增大,形成新的“金属岛” 。
这一模型得到了热电动势、电导与电场依赖性、声频电导、ESR、IR 和 NMR 研究的支持传输性质研究表明,两个“金属岛”之间存在适当尺寸的“障碍” ,这一势垒的存在妨碍了高导电率的获得 ③极子和双极化子相互转化模型 Somerset 和 Klink[20]等提出孤子(Soliton)理论(简称 SSH 理论)来解释聚乙炔电导率及其物理性能我国学者王慧中[21]等提出的掺杂态聚苯胺单极化子和双极化子相互转化的结构模型,比较合理的解释了聚苯胺的导电机理 据乙炔具有规整的单双键交替的主链结构, 这种一维的主导电子态之间强的相互作用,从拓扑学上来说,主要是由能量相同的两个不同的相 A 和相 B 的交界处形成“畴壁” ,即“孤子” ,它可带电或不带电,而且可以在链上运动根据这一理论,孤子、极化子(Polaron)和双极化子(Bipolaron)被视为导电高分子的导电载流子极化子、极子和孤子来自不同的简并态,极子是孤子形成的稳定形式,他们的物理实质都是能隙间的定域态对于掺杂态的聚苯胺,导电载流子只能是单极化子或双极化子 1-2-4 聚苯胺的合成 1-2-4-1 化学氧化法 1-2-4 聚苯胺的合成 1-2-4-1 化学氧化法 聚苯胺的合成方法有化学氧化法和电化学合成法两种: 化学氧化法是在酸性介质的条件下,用强氧化剂进行氧化苯胺单体,可得到掺杂态的聚苯胺。
化学微纳米结构聚苯胺的制备与性能研究 - 6 - 合成法合成工艺简单,成本较低,适于大量生产化学法制备聚苯胺主要受氧化剂的种类和浓度,反应介质的酸度,单体的浓度和反应温度等因素的影响目前,主要使用的氧化剂有:(NH4)2S2O8,K2Cr2O8,FeC13,过氧化酶[22,23]等氧化剂浓度过高会产生大量的苯胺齐聚物或溶于水及甲醇的物质氧化剂用量过大还会造成聚苯胺的降解 质子酸也是影响苯胺氧化聚合的聚合度和电性能一个重要因素 合成聚苯胺的反应一般在强酸性溶液中进行 它的作用主要是提供一定的酸度, 同时以掺杂剂的形式进入聚苯胺分子链赋予其一定的导电性通常所用的质子酸有盐酸、硫酸、磷酸、高氯酸等无机酸[24]和十二烷基苯磺酸(DBSA),樟脑硫酸(CSA),苯磺酸(SA),乙酸。