Potentiality of Hydrocarbon Membrane for Durability Improvement of Pt and PtCo Alloy Catalyst and Pt Loading Reduction

One of the major cost drivers in polymer electrolyte fuel cells (PEFCs), particularly for automotive application, is the use of platinum-based electrodes to facilitate electrochemical reactions such as hydrogen oxidation and oxygen reduction. Improving the durability of Pt and PtCo alloy catalyst shall reduce total active area and/or Pt loading per unit active area without any sacrifice in performance of fuel cell stacks, and it can also significantly be beneficial to the reduction of total Pt usage on fuel cell vehicles (FCVs). Catalyst durability during fuel cell operation remains a key challenge to developing the fuel cell system with acceptable overall cost in automotive applications.

Toray has been developing advanced hydrocarbon (HC) membranes to give a better total solution in terms of overall cost reduction of fuel cell systems, which includes  i) the potentiality for durability improvement of Pt and PtCo alloy catalyst and Pt loading reduction due to less Pt particle dissolution, ii) no emission of super acids such as HF and perfluorosulfonic acids, iii) low gas crossover,  and iv) environmental friendliness, in comparison with conventional PFSA membranes.

We will describe in the meeting that Toray HC membrane would potentially improve the durability of PtCo alloy catalyst owing to less Pt particle dissolution, and thereby reduce total active area and/or Pt loading per unit active area by 45% ((1-0.24V/0.43V)x100) vs Nafion HP as a reference in case judging at 1000 hours in the accelerated chemical and mechanical durability test. We hope Toray HC membranes could help to form a pathway toward FCV wide commercialization.

ACKNOWLEDGEMENT

This work was partially supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan.