最有希望的燃料电池技术之一是质子交换膜或聚合物电解质燃料电池。聚合物型燃料电池可在低温下(低于100度)达到高的输出密度，从而使其成为可用于车辆的候选电池。但是，通常用在这些燃料电池中的电解质有其缺陷，例如它们需要潮湿条件，其操作温度上限为100度左右。Haile等人提出了一种可代替标准磺酸盐电解质的方法。早在80年代，固体酸(如KHSO4)就被认为是良好的质子导体，但却因其在水中的可溶性而被认为几乎没有技术价值。现在，研究表明，用CsHSO4做成的一种膜具有很好的电化学性能，在温度高至160度时仍可工作。(Letters, p. 910;News and Views)
Abstract
Solid acids as fuel cell electrolytes
Sossina M. Haile, Dane A. Boysen, Calum R. I. Chisholm and Ryan B.Merle
Fuel cells are attractive alternatives to combustion engines forelectrical power generation because of their very high efficiencies and lowpollution levels. Polymer electrolyte membrane fuel cells are generallyconsidered to be the most viable approach for mobile applications. However,these membranes require humid operating conditions, which limit the temperatureof operation to less than 100C; they are also permeable to methanol andhydrogen, which lowers fuel efficiency. Solid, inorganic, acid compounds (orsimply, solid acids) such as CsHSO4 and Rb3H(SeO4)2have been widely studied because of their high proton conductivities andphase-transition behaviour. For fuel-cell applications they offer theadvantages of anhydrous proton transport and high-temperature stability (up to250C). Until now, however, solid acids have not been considered viablefuel-cell electrolyte alternatives owing to their solubility in water andextreme ductility at raised temperatures (above approximately 125C). Here weshow that a cell made of a CsHSO4 electrolyte membrane (about 1.5mmthick) operating at 150--160C in a H2/O2 configurationexhibits promising electrochemical performances: open circuit voltages of 1.11Vand current densities of 44mAcm-2 at short circuit. Moreover, thesolid-acid properties were not affected by exposure to humid atmospheres.Although these initial results show promise for applications, the use of solidacids in fuel cells will require the development of fabrication techniques toreduce electrolyte thickness, and an assessment of possible sulphur reductionfollowing prolonged exposure to hydrogen.
选自《自然》中文版nature asia