Accession Number:

AD1101036

Title:

Improving PEMFC Performance Using Short-Side-Chain Low-Equivalent-Weight PFSA Ionomer in the Cathode Catalyst Layer

Descriptive Note:

Journal Article - Open Access

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States

Report Date:

2018-04-13

Pagination or Media Count:

12.0

Abstract:

Incorporation of short-side chain SSC ionomers in the catalyst layers CL of proton exchange membrane fuel cells PEMFCs can improve performance, particularly at low relative humidities. We attempt to understand this effect by comparing PEMFCs with cathode CLs containing Pt on carbon-black CB and either SSC Aquivion ionomer or a standard long-side-chain LSC Nafion ionomer at 50 and 100 RH. The CL microstructures are characterized for their micro- and mesoporosity. The CLs are formed into PEMFCs and probed with polarization curves, cyclic voltammetry, O-2 gain, limiting current measurements, and electrochemical impedance spectroscopy. PEMFCs containing the SSC ionomer in the cathode CL have superior polarization curves compared to those containing the LSC ionomer in the mass transport region under all conditions. We find that the SSC ionomer imparts lower proton transport resistances, lower charge transfer resistance to the cathode near 0.60 V, and lower mass transport resistance at 0.40 V. We attribute some of the performance improvements to the superior proton conductivity of the SSC ionomer, and the remainder to the higher micropore volume in the SSC-containing CLs which can more effectively evaporate water to the gas phase, improving both the availability of catalyst sites for charge transfer and mesopores for gas transport. C The Authors 2018. Published by ECS.

Subject Categories:

  • Electrochemical Energy Storage
  • Electrochemical Energy Storage

Distribution Statement:

APPROVED FOR PUBLIC RELEASE