聚磷酸铵基质子复合电解质在中温燃料电池中的应用

用溶胶-凝胶法制备了复合固体电解质xNH4PO3-SiO2(x=1、2、4),并研究了该电解质在125～250℃范围内的导电性能以及电池性能。复合电解质的相结构分析表明,NH4PO3和SiO2在溶胶-凝胶法制备过程中没有发生化学反应;复合电解质的电导率随着NH4PO3含量增大而提高,并与NH4PO3的形态相关。电导活化能随NH4PO3含量的上升而下降,表明在sol-gel法制备的复合电解质中,起电导作用的主要是NH4PO3,而SiO2主要起支撑作用;电导率随着环境气氛中含水量的提高而提高。以湿氢气为燃料和干氧气为氧化剂,用复合电解质制备的燃料电池最大功率在250℃为4.8mW/cm2。

Ammonium polyphosphate proton conductor composites as electrolyte for intermediate temperature fuel cells

Proton-conductive composite electrolytes consisting of xNH4PO3-SiO2(x=1,2,4) was synthesized by a sol-gel method.X-ray diffraction investigation showed that NH4PO3 was chemically stable in the process of sol-gel preparation.The conductivity of the resulted composites was measured with impedance spectroscopy.The conductive behavior was improved by increasing the molar ratio of NH4PO3.Meanwhile the activation energy for conductivity decreased with NH4PO3 content.This indicates that NH4PO3 is responsible for the high conductivity and SiO2 serves as a supporting matrix.The proton conductivity was dramatically enhanced by increasing the water content,indicating that the effect of water is significant.Maximum power density was 4.8mW/cm2 at 250℃ when humidified hydrogen and oxygen were used as the fuel and oxidant.