Initial Performance and Durability of Ultra-Low Loaded NSTF Electrodes for PEM Electrolyzers

Abstract

Water based electrolyzers offer a promising approach for generating hydrogen gas for renewable energy storage. 3M's nanostructured thin film (NSTF) catalyst technology platform has been shown to significantly reduce many of the performance, cost and durability barriers standing in the way of H 2 /air PEM fuel cells for vehicles. In this paper we describe results from the first evaluations of low loaded NSTF catalysts in H 2 /O 2 electrolyzers at Proton OnSite and Giner, Inc. Over two dozen membrane electrode assemblies comprising nine different NSTF catalyst types were tested in 11 short stack durability tests at Proton OnSite and 14 performance tests in 50 cm 2 single cells at Giner Electrochemical Systems. NSTF catalyst alloys of Pt 68 Co 29 Mn 3 , Pt 50 Ir 50 and Pt 50 Ir 25 Ru 25 , with Pt loadings in the range of 0.1 to 0.2 mg/cm 2 , were investigated for beginning-of-life performance and durability up to 4000 hours as both electrolyzer cathodes and anodes. Catalyst composition, deposition and process conditions were found to be important for meeting the performance of standard PGM blacks on electrolyzer anodes while using only 10% as much PGM catalyst. Analyses of MEA's after the durability tests by multiple techniques document changes in catalyst alloy composition, loading, crystallite structure and support stability.Pure pressurized hydrogen gas offers a convenient and predictable means for storing and transporting convertible energy from renewable or other energy sources for powering fuel cells for vehicle, portable and back-up power applications. Renewable energy sources such as wind and solar will require large, efficient and versatile energy storage means for load leveling over wide periods of time covering seconds to days for which electrochemical storage means offer many advantages. Regenerative fuel cells and H 2 /O 2 electrolyzers used for energy storage are key examples. Water based electrolyzers with higher heating value voltage efficiencies of 75% are projected to be able to produce H 2 in the $3-$4/kg range, competitive with current gasoline prices, at reasonable electricity costs on the order of $0.05/kW-Hr. [1][2][3][4] Proton exchange membrane (PEM) based water electrolyzers offer a promising pathway to efficient hydrogen production because of a small installation footprint, ease of handling the solid polymer electrolyte and ability to generate high pressure hydrogen with only deionized water and electricity as inputs. Commercial PEM electrolyzer costs based on current technology are excessive due both to low volume (batch) system assembly and high stack component material costs. However, the electrolyzer stacks and their internal components, viz. separator plates, PEM's and catalysts have cost factors that could benefit significantly from the technology improvements that PEM fuel cell development has enabled over the past decade or more. With respect to the electrocatalysts, current commercial PEM electrolyzers use 2 mg/cm 2 or more of precious group metals (PGM) on their anodes (oxygen ev...

High-Resolution Analysis of Ionomer Loss in Catalytic Layers after Operation

“…Journal of The Electrochemical Society, 165 (6) F3139-F3147 (2018) can be chosen to be most relevant for the intended operation, i.e. under humid conditions for fuel cell application or under water for electrolyser application.…”

Electrochemical performance modeling of a proton exchange membrane electrolyzer cell for hydrogen energy

“…In particular, a new ohmic loss model with electrode porosity and interfacial resistance are integrated for the first time. In order to effectively analyze the performance of PEM electrolyzer cells, the present model is firstly computed and validated with recent experimental data [29]. In this validation case, the corresponding operating temperature value was 80 C and the PEM thickness was 178 microns.…”

Remarkable Mass Activities for the Oxygen Evolution Reaction at Iridium Oxide Nanocatalysts Dispersed on Tin Oxides for Polymer Electrolyte Membrane Water Electrolysis

“…Nevertheless, conventional PEMWE cells are very expensive due to their use of a large amount of noble metals such as Pt and/or Ir as electrocatalysts (2 mg Pt+Ir cm −2 or more in each electrode), in addition to their use of costly polymer electrolyte membranes. 3,6 To solve the catalyst problem, one possible approach is to use nano-sized catalysts highly dispersed on support materials in place of noble metal blacks with large particle sizes, typically over 50 nm. For the support material at the anode, high durability at the high potentials of the oxygen evolution reaction (OER) under acidic conditions is required.…”