Hybrid-type Fuel Cell Using Fe-CI Redox System

Abstract

A hybrid-type fuel cell system consisting of power generation with the H₂/FeCl₃ couple and air oxidation of FeCl₂,
was studied. A cell was constructed with graphite gas diffusion electrodes and an ion-exchange membrane.
The fuel cell characteristics (voltage-current density relationship for Eq.1) was examined for a variety of (i) cell temperature (50-70°C), (ii) ion-exchange membranes (Neosepta C66-5 T, Nafion-125, or Aciplex K-I01), and (iii) the amount of platinum catalyst loaded on the anode (0-45 mgPt/cm²). A typical cell voltage of O.6 V and a current density of 100mA/cm² were attained at 70°C for 2 mgPt/cm². Eq.2 was examined with a bubble-type ract or for a variety of (i) bubble diameter (0.9 and O.3 mm), (ii) reaction temperature (70 and 90°C), (iii) oxygen partial pressure (0.8 and 1.8 atm), and (iv) liquid composition (1.5-3.0molFeCl₂/kgH₂O, 2.0-3.5 mol HCl/kgH₂O). The regeneration efficiency was 90% for bubble diameter 0.3 mm, 90°C, 1.8 atm O₂, 1.5 mol FeCl₂/kgH₂O, and 3.5 mol HCl/kgH₂O. Based on these experimental results, the feature of the present hybrid-type fuel cell system is discussed in comparison with the phosphoric acid type fuel cell.