The Characterization of an Alkaline Fuel Cell That Uses Hydrogen Storage Alloys

Abstract

The characterization of new type of alkaline fuel cell based on oxidation of chemical hydride has been studied. The chemical hydride can be used as a new fuel source in a fuel cell system. As a result, we have discovered that the electrochemical reaction rate is higher at a normal temperature compared with cells containing other hydrogen fuels where a hydrogen-releasing agent, NaBH4, is added to an aqueous alkaline solution of electrolyte as hydrogen fuel. That is, the fuel can be supplied very simply for the cell. If air is supplied to the oxygen cathode made of highly dispersed platinum particles supported in high-surface-area carbon paper, and the hydrogen releasing agent is fed to the alkaline solution of electrolyte at the side of metal hydride anode false(ZrCr0.8Ni1.2 alloy), the cell can produce electric current continuously. Also it can be operated at a normal temperature and produce a large amount of energy due to its high energy density of 6,000 Ah/kg or more (for NaBH4 or KBH4false). Therefore, the developed cell has higher electrochemical reaction rate and energy density than the conventional fuel cells using other hydrogen sources. © 2002 The Electrochemical Society. All rights reserved.

Agni-catalyzed anode for direct borohydride fuel cells

“…These CV features demonstrated that the AgNi surface is more favorable for hydrogen adsorption than pure Ag surface. As suggested in previous work [4][5][6][9][10][11], the electrochemical oxidation of an BH − 4 ion proceeds through stepwise breakdown of its four B-H bonds involving the formation of adsorbed hydrogen atom during each step. As a result, the metal surfaces with higher affinity for hydrogen adsorption, such as Pt, Ni and hydrogen storage alloys, exhibited strong catalytic activity for borohydride oxidation.…”

“…In the literature [4,6,9,14], a number of reaction mechanisms have been proposed to explain the very different oxidation behaviors of BH − 4 on different types of metallic surface. It has been well recognized that a complete electrochemical oxidation of BH − 4 can be realized on Au surface [6,14,21] and sufficiently polarized Pt surface [5], at which the anodic oxidation of BH − 4 ions proceeds mainly through the direct electrochemical processes as given by…”

“…The major problem is the hydrolysis of BH − 4 ions spontaneously during discharge on a variety of electrocatalysts, causing decreasing coulombic efficiency and poor utilization of BH − 4 [7][8][9][10]. For example, the faradic efficiency of BH − 4 is less than 50% on hydrogen storage alloys [11], 50% at most on nickel [12,13], and below 50% on Pt-catalyzed anode at low polarization [6].…”

Studies of Modified Hydrogen Storage Intermetallic Compounds Used as Fuel Cell Anodes

“…On the other hand, the Ti-based alloy pioneered by Viden et al in the 1970s [23] showed promising electrochemical properties. Given the newly technical advances on the PEMFC, Ti-based alloys would deserve further reinvestigation, as well as other functional materials [24][25][26].…”

Carbon supported Cu-Pd nanoparticles as anode catalyst for direct borohydride-hydrogen peroxide fuel cells

“…Ni [25], Co [26][27][28] and Cu [29,30], and hydrogen storage alloys [26,[31][32][33]. In the earlier literatures, gold is well known as an effective electrocatalyst for the BH 4 -oxidation, with the advantage of having almost no catalytic effect on the hydrolysis reaction, and can lead to nearly 8 mol of exchanged electrons per mole of BH 4 - [12][13][14].…”