A Fuel Cell Development for Using Borohydrides as the Fuel

Abstract

A fuel cell was developed using borohydride solutions as the fuel. The cell consisted of an anode made of a Zr-Ni alloy, a cathode made of Pt/C, and a Na+Na+ form Nafion membrane as the electrolyte. The borohydride-fueled cell showed an open-circuit voltage of 1.3 V, compared with 1.0 V for a hydrogen gas-fueled one. The anode exhibited a small polarization property compared with the cathode. The cathode polarization was the main reason for the cell voltage drop with increasing currents. When a Nafion membrane was used as the electrolyte, it was confirmed that cations (Na+)(Na+) were the charge carrier in it. Compared with Nafion 112 membrane, Nafion 117 membrane demonstrated a considerable resistance to borohydride crossover and resulted in acceptable cell performance. However, there are several problems such as H2H2 evolution during operation, BH4−BH4− crossover, NaOH accumulation at the cathode, and NaBO2NaBO2 accumulation at the anode in recent systems. Further effort is needed to develop the fuel cell using borohydrides as the fuel. © 2003 The Electrochemical Society. All rights reserved.