Influence of Ionomer/Carbon Ratio on the Performance of a Polymer Electrolyte Fuel Cell

Mika Eguchi,Keishiro Komatsu,Takamitsu Onuma,Koki Baba,Maya Kobori,Yoshio Kobayashi,Kazuma Yoshida,Kenta Iwasawa,Katsuhiro Uno,Toshihiro Ando,Mikka Nishitani-Gamo

doi:10.3390/polym4041645

Abstract

We have used fibrous carbon materials as polymer electrolyte fuel cell (PEFC) electrodes. We have examined the influence of the ionomer/carbon ratio on the performance of the PEFCs. The Marimo carbon is a kind of carbon with a spherical shape, and consists of carbon nanofilaments. Fibrous carbon materials have large specific surface areas without fine pores. The reactant gases and generated water can easily diffuse among the nanofilaments. The ionomer plays two roles; one is a proton transfer activity, and the other is binding the catalyst electrodes. An excess ionomer interferes with the diffusion of gases. The ionomer/carbon ratio should affect the performance of the PEFC, especially at a high current density.

Highlights

The membrane-electrode assembly (MEA) is used in a polymer electrolyte fuel cell (PEFC)
Hydrogen was supplied to the anode during the Cyclic voltammetry (CV) measurements
The previously reported electrodes with Pt particles of 2–3 nm diameters indicated a good performance for the PEFC [10]

Summary

Introduction

The membrane-electrode assembly (MEA) is used in a polymer electrolyte fuel cell (PEFC). Many studies have been reported regarding the influence of the ionomer/carbon (I/C) ratio as the electrolyte and binder. Carbon blacks are well known to be a catalyst support for the PEFCs. In recent years, fibrous carbon materials are attracting attention due to their high electric conductivity and water repellency. Fibrous carbon materials have a small diameter and long length that form large specific surface areas. The carbon nanofilament (CNF) is one of the fibrous carbon materials [7] This structure should be favorable for supplying reactant gases and removing the product water. Different structures of carbon materials should produce different performances for the PEFC and require different I/C ratios. We prepared MEAs using a Pt catalyst supported on CNFs with different amounts of ionomer, and investigated the influence of the I/C ratio. We indicated the optimum I/C ratio when using CNFs for the PEFC

Experimental Section

Results and Discussion

Conclusions