BINDER FOR FUEL CELL, COMPOSITION FOR ELECTRODE FORMATION, ELECTRODE, AND FUEL CELL USING THE ELECTRODE
申请人:Mitsui Chemicals, Inc.
公开号:EP1788649A1
公开(公告)日:2007-05-23
This invention provides a binder for a fuel cell which has high adhesion, low methanol solubility, high methanol permeability and high proton conductivity, a composition for electrode formation, an electrode for a fuel cell, and a fuel cell using them. The binder is particularly suitable for a binder for a direct methanol type fuel cell which requires high proton conductivity.
The binder for a fuel cell comprises a block copolymer which comprises a block having a repeating structural unit of a divalent aromatic group that contains a protonic acid group and a block having a repeating structural unit of a divalent aromatic group that does not contain a protonic acid group, and which has a glass transition temperature (Tg) of 180 °C or less. In particular, it is preferable that the block copolymer has an ion exchange group equivalent of from 200 to 1,000 g/mole and a weight retention ratio of 90% or more as measured by immersion in a 64 weight % aqueous methanol solution at 25 °C for 24 hours.
本发明提供了一种用于燃料电池的粘合剂,它具有高粘合力、低甲醇溶解度、高甲醇渗透性和高质子传导性,还提供了一种用于电极形成的组合物、一种燃料电池电极以及一种使用它们的燃料电池。这种粘结剂特别适用于要求高质子传导性的直接甲醇型燃料电池的粘结剂。
燃料电池用粘结剂由嵌段共聚物组成,嵌段共聚物包括具有二价芳香族重复结构单元的嵌段和具有二价芳香族重复结构单元的嵌段,前者含有质子酸基,后者不含质子酸基,且玻璃化转变温度(Tg)为 180 °C 或更低。具体而言,嵌段共聚物最好具有 200 至 1 000 克/摩尔的离子交换基团当量,以及 90%或更高的重量保持率(通过在 25 °C 下将其浸泡在 64 重量百分比的甲醇水溶液中 24 小时测得)。