發(fā)布時間：2018-03-12 12:22

  本文選題：甲醇　切入點(diǎn)：質(zhì)子交換膜　出處：《吉林大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：當(dāng)前,質(zhì)子交換膜的甲醇透過率高和成本高及膜電極集合體的制備技術(shù)復(fù)雜是限制直接甲醇燃料電池性能提升的兩個重要問題,也是阻礙直接甲醇燃料電池實(shí)現(xiàn)商業(yè)化的關(guān)鍵。為了克服現(xiàn)有質(zhì)子交換膜的缺點(diǎn),我們開發(fā)了新型質(zhì)子交換膜,從磺化度、膜電極制備等方面提升了膜的實(shí)際工作性能。主要研究內(nèi)容如下:1.探討甲醇透過率和質(zhì)子電導(dǎo)率對DMFC電池性能影響。通過調(diào)控聚合物單體比例合成了一系列具有不同磺化度的磺化聚芳醚酮砜(SPAEKS)膜,主要討論了甲醇透過率和質(zhì)子電導(dǎo)率對DMFC電池性能的直接影響。結(jié)果顯示,磺化度提升與電導(dǎo)率的提升存在相關(guān)性,同時在高磺化度下親水團(tuán)簇的尺寸和數(shù)量的增加會提高單個磺酸集團(tuán)的質(zhì)子傳導(dǎo)能力,該協(xié)同效應(yīng)使得電導(dǎo)率迅速增加。同時,由于與質(zhì)子共用傳輸通道,甲醇的透過性也會隨磺化度提高迅速提升。因此,磺化度提升對電池性能具有正反兩面的貢獻(xiàn):一方面能夠提高材料離子電導(dǎo)率,從而降低電池的內(nèi)阻;另一方面,甲醇的高透過率會導(dǎo)致燃料損失和嚴(yán)重的陰極混合電位問題,從而嚴(yán)重影響電池輸出功率密度和能量效率。通過對不同膜在電池中的測試發(fā)現(xiàn)SPAEKS-0.6H為最適合的膜材料,以其為電解質(zhì)的MEA放電性能可達(dá)50 m W cm-2,與Nafion膜材料相當(dāng)。2.制備新型磺化聚醚醚酮膜及其MEA制備工藝的優(yōu)化。從固體電解質(zhì)水電解(SPE)技術(shù)的核心部件--膜電極集合體(MEA)入手,針對現(xiàn)有商用SPE水電解設(shè)備價格昂貴的缺點(diǎn),將一種可能替代現(xiàn)有SPE膜的磺化聚醚醚酮聚合物制備成MEA�？朔酥苽渲袩釅哼^程出現(xiàn)的問題,考察了催化劑與離聚物質(zhì)量比、熱壓溫度、熱壓時間三個影響因素對膜電極性能的影響。發(fā)現(xiàn)催化劑與離聚物質(zhì)量比、熱壓溫度、熱壓時間三個因素會對膜電極的性能造成明顯的影響;根據(jù)極化曲線和計時電流的測試結(jié)果,催化劑與離聚物質(zhì)量比、熱壓溫度、熱壓時間三個因素過高和過低都不利于膜電極的性能表現(xiàn);催化劑與離聚物質(zhì)量比在5:1,熱壓溫度在90℃到120℃之間,熱壓時間60 s左右是制備磺化聚醚醚酮膜電極較為合適的條件。3.采用原位沉積還原法制備超低鉑載量的MEA。通過一系列物理化學(xué)表征表明采用原位沉積還原法制備的催化劑粒徑大小均勻,采用Nafion聚合物所制備的催化劑粒徑尺度全部分布在2nm-3nm間,而采用陰離子聚合物所制備的催化劑粒徑尺度分布在0.6-1.6nm之間。利用原位沉積還原法所制備的MEA開路電壓最高達(dá)0.83V,與常規(guī)熱壓法所制備的電池相比,在開路僅下降15%的情況下,催化劑載量降低了87.5%。為新型高熱穩(wěn)定性質(zhì)子交換膜在電池中的進(jìn)一步應(yīng)用奠定基礎(chǔ)。
[Abstract]:At present, the high methanol transmittance and high cost of proton exchange membrane and the complex preparation technology of membrane electrode collection are two important problems that limit the performance improvement of direct methanol fuel cell. In order to overcome the shortcomings of the existing proton exchange membrane, we have developed a new type of proton exchange membrane, from the degree of sulfonation, The main research contents are as follows: 1. The effects of methanol transmissivity and proton conductivity on the performance of DMFC batteries were investigated. A series of polymer monomers were synthesized by adjusting the ratio of polymer monomers. Sulfonated polyaryl ether ketone sulfone (SPAEKS) membrane with different degree of sulfonation, The direct effects of methanol transmittance and proton conductivity on the performance of DMFC cells are discussed. At the same time, increasing the size and number of hydrophilic clusters at high sulfonation degree can improve the proton conductivity of single sulfonic acid group, and this synergistic effect makes the conductivity increase rapidly. At the same time, because of sharing the transport channel with proton, The permeability of methanol also increases rapidly with the increase of sulfonation degree. Therefore, the enhancement of sulfonation degree has both positive and negative contributions to the performance of the battery: on the one hand, it can increase the ionic conductivity of the material, thereby reducing the internal resistance of the battery; on the other hand, The high transmission rate of methanol will lead to fuel loss and serious cathode mixing potential problems, which will seriously affect the output power density and energy efficiency of the battery. It is found that SPAEKS-0.6H is the most suitable membrane material through the measurement of different membranes in the cell. The discharge performance of MEA with MEA as electrolyte is up to 50 m W cm ~ (-2), which is equivalent to that of Nafion membrane material. The preparation of new sulfonated polyether ether ketone membrane and its preparation process of MEA are optimized. The core component of solid electrolyte water electrolysis is membrane electrode aggregation (MEA). A sulfonated polyether ether ketone polymer, which can replace the existing SPE membrane, was prepared by using a sulfonated polyether ether ketone polymer instead of the existing SPE membrane. The problem of hot pressing process was overcome and the mass ratio of catalyst to ionomer was investigated. It is found that the mass ratio of catalyst to ionomer, the temperature of hot pressing and the time of hot pressing have obvious influence on the performance of membrane electrode. According to the results of polarization curves and chronoamperometric measurements, the performance of the membrane electrode was affected by three factors: the mass ratio of catalyst to ionomer, the temperature of hot pressing and the time of hot pressing. The mass ratio of catalyst to ionomer is 5: 1, and the hot pressing temperature is between 90 鈩，

本文編號：1601542