摘 要

燃料电池（Fuel Cell）是一种将氧化剂和燃料中的化学能直接转变为电能的新型能量转换装置。质子交换膜燃料电池（PEMFC）是继碱性燃料电池、磷酸燃料电池、熔融碳酸盐燃料电池和固体氧化物燃料电池以后发展起来的第五代燃料电池。质子交换膜具有转化效率高、低温启动快等有点，被认为是清洁能源转换技术之一。质子交换膜（Proton Exchange Membrane）是质子交换膜燃料电池的关键组成部分。目前实现商业化应用的质子交换膜是Nafion膜，它在低温高湿度条件下质子传导率高，在高温条件下（＞100℃）由于膜内水分蒸发导致质子传导率急剧下降，此外，Nafion膜价格昂贵制备过程繁琐。因此，开发出在高温条件下性能优良价格低廉的质子交换膜是PEMFC研究的重点。本文以氨基三甲叉膦酸（ATMP）、聚苯并咪唑（PBI）和2-(3,4-环氧环己基)乙基三甲氧基硅烷（EHTMS）为原料，采用溶胶-凝胶法制备出了聚硅氧烷膦酸/PBI高温质子交换膜。傅立叶红外（FT-IR）表明，ATMP和EHTMS反应生成了聚硅氧烷膦酸。FT-IR、XRD和SEM表明，体系存在氢键，膜中没有游离的ATMP。对制备的膜进行热稳定性、化学稳定性、机械性能、质子传导性能等进行了研究。研究表明，制备的膜具有具有较高的热稳定性和化学稳定性，机械性能明显优于ATMP/PBI膜，但质子传导率不高（在140℃名义上的无水条件下为0.034S/cm）。

关键词：质子交换膜，ATMP，PBI，质子传到率

Abstract

Fuel cell is a new energy conversion instrument, which converts the chemical energy stored in the oxide and fuel to the electrical energy. Proton exchange membrane fuel cell (PEMFC) is the fifth generation of fuel cell after the alkaline fuel cell, phosphorous fuel cell, molten carbonate fuel cell and solid oxide fuel cell. Compared to the other fuel cells, PEMFC has a lot of advantages, such as efficient energy transformation and fast initiation. It is considered that PEMFC is one of the most promising electrochemical energy conversion devices. PEM (Proton Exchange Membrane) is one of the key components for PEMFC. Currently, the most commonly used PEM for PEMFC is Nafion membrane. The proton conductivity of Nafion is considerablewhen the operation temperature under 80℃. In fact, proton conductivity of Nafion is very dependent on water content of membrane. As we all know, proton conductivity of Nafion falls sharply when the operation temperature above 100℃, which is due to the evaporation of moisture.Thus, the development of new type of PEM becomes an important project in the field of high temperature and low humidity PEMs. A series of high temperature and low humidity PEMs based on amino trimethylene phosphonic acid (ATMP) were studied. Polysiloxane phosphonic acid-doped Polybenzimidazole high temperature membrane is fabricated from amino trimethylene phosphonic acid (ATMP), polybenzimidazole (PBI) and epoxycyclohexylethyltrimethoxysilane (EHTMS) by sol-gel process. Polysiloxane phosphonic acid instead of phosphoric acid is used as proton conductor to prevent acid leaks. The samples with different amounts of ATMP were characterized using FT-IR, XRD and SEM. The results suggested thatall of the ATMP is chemically bonded to EHTMS and polysiloxane phosphonic acid is successfully prepared; hydrogen bond form between PBI and polysiloxane phosphonic acid. The properties of membranes such as thermostability, chemical durability, water absorption, swelling ratio, proton conductivity, and proton conductive activation energy were measured.Results revealed that polysiloxane phosphonic acid doped PBI membranes show good thermostability and chemical durability; the water absorption, swelling ratio can meet the need of fuel cell; the proton conductivity of the samples depends on temperatureup to a maximum of 0.034 S/cm^–1 at 140 °Cunder nominally anhydrous conditions; the proton transfer with “Grothus mechanism”.Furthermore, the tensile strength of the membrane with 10% PBI is 18.3MPa.

Key words: Proton exchange membrane, ATMP, PBI, proton transfer mechanism

目录

第1章 绪论 1

1.1前言 1

1.1.1质子交换膜燃料电池 1

1.1.2 质子交换膜燃料电池的工作原理 1

1.1.3 质子交换膜 2

1.2 质子交换膜研究进展 3

1.3 聚苯并咪唑基质子交换膜研究进展 5

第2章聚硅氧烷膦酸掺杂PBI高温质子交换膜的性能研究 10

2.1 实验部分 10

2.1.1 实验试剂及仪器 10

2.1.2 实验步骤 11

2.1.3 性能测试 11

2.2 结果与讨论 14

2.2.1 红外分析 14

2.2.2 XRD分析 16

2.2.3 质子传导性分析 17

2.2.4 氧化稳定性分析 19

2.2.5 形貌分析 20

第3章 结论 22

参考文献 23

致谢 26

第1章 绪论

1.1前言

1.1.1质子交换膜燃料电池

质子交换膜燃料电池（PEMFC），顾名思义，它是以固体聚合物为质子交换膜的燃料电池。PEMFC是在碱性燃料电池、磷酸燃料电池、熔融碳酸盐燃料电池和固体氧化物燃料电池的基础上发展起来的第五代燃料电池。PEMFC的发展受到世界范围内研究学者们的广泛关注是由于其高效节能、环境友好、电流密度大（1-4A/cm²，0.6V），便于维护、冷启动时间段、体积小、重量轻等优点，正是基于这些特点PEMFC被认为适合应用于军事和民用领域^[1-3]。

PEMFC除了具有上述难能可贵的优点，它还具有一些显而易见的缺点，例如：质子交换膜的价格普遍偏高，催化剂易被杂质气体毒化，催化剂成本高等缺点，在今后PEMFC的研究中应注重发扬其优点克服其缺点。

1.1.2 质子交换膜燃料电池的工作原理

PEMFC的电极反应与其它四种燃料电池类似。迄今为止，关于PEMFC的工作原理有很多种说法，其中最令人信服的是：PEMFC的工作过程是电解水的逆过程，下面用以氢气为燃料的PEMFC为例，简要说明PEMFC的工作原理，其工作原理如图1-1所示。PEMFC反应过程为：氢气经过阳极气室在阳极催化剂的催化作用下发生还原反应，阳极反应如反应式（1-1）所示，氢气在催化剂的作用下成质子和电子，质子在PEMFC内部通过质子交换膜经阳极到达阴极，由于质子交换膜具有选择透过性，产生的电子必须经由外接电路从电池的负极传导到正极（在这个过程中形成电流，可以对外加电路供电），质子和电子在电池的阴极相遇并与氧气发生一系列的电化学反应，具体反应过程如反应式（1-2）所示，总的化学反应方程式如反应式（1-3）所示。

H₂=2H 2e^- (1-1)