Characteristics of Matrix Retaining Electrolyte in a Phosphoric Acid Fuel Cell Analyzed by A.C. Impedance Spectroscopy

복소임피던스법에 의한 인산형 연료전지용 전해질 매트릭스 특성

  • 윤기현 (연세대학교 세라믹공학과) ;
  • 장재혁 (연세대학교 세라믹공학과) ;
  • 허재호 (연세대학교 세라믹공학과) ;
  • 김창수 (한국에너지기술연구소) ;
  • 김태희 (안동대학교 재료공학과)
  • Published : 1995.02.01

Abstract

Materials retaining electrolyte of a phosphoric acid fuel cell (PAFC) have been prepared with SiC powder to SiC whisker mixing ratios of 1:1, 1:2, 1:3, 1:4, 0:1 by a tape casting method. When 3wt% dispersant (sorbitan monooleate) is added to a matrix, the porosity of the matrix decreases a little while the bubble pressure and area of the matrix increase remarkably in comparison with no dispersant content. Effect of the electrolyte resistance and the polarization resistance on perfomance of a PAFC has been investigated using A.C. impedance spectroscopy. With the increase of whisker content, the electrolyte resistance decreases due to the increase of porosity and acid absorbancy, and the polarization resistance increases due to the increase of surface roughness. The polarization resistance affects current density predominantly at the higher potential than 0.7V becuase the polarization resistance is considrably larger than the electrolyte resistance. Both the electrolyte resistance and the polarization resistance affect current density near 0.7V of the fuel cell operating potential because they have similar values. The electrolyte resistance affects current density predominantly at the lower potential than the fuel cell operating potential because the electrolyte resistance is larger than the polarization resistance.

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