Hydrocarbon proton conducting polymers for fuel cell catalyst layers

Abstract

Proton exchange membrane fuel cells (PEMFCs) employing proton conducting membranes are promising power sources for automotive applications. Perfluorosulfonic acid (PFSA) ionomer represents the state-of-the-art polymer used in both the membrane and catalyst layer to facilitate the transport of protons. However, PFSA ionomer is recognized as having significant drawbacks for largescale commercialization, which include the high cost of synthesis and use of fluorine-based chemistry. According to published research much effort has been directed to the synthesis and study of non-PFSA electrolyte membranes, commonly referred to as hydrocarbon membranes, which has led to optimism that the less expensive proton conducting membranes will be available in the not-so-distant future. Equally important, however, is the replacement of PFSA ionomer in the catalyst layer, but in contrast to membranes, studies of catalyst layers that incorporate a hydrocarbon polyelectrolyte are relatively sparse and have not been reviewed in the open literature; despite the knowledge that hydrocarbon polyelectrolytes in the catalyst layer generally lead to a decrease in electrochemical fuel cell kinetics and mass transport. This review highlights the role of the solid polymer electrolyte in catalyst layers on pertinent parameters associated with fuel cell performance, and focuses on the effect of replacing perfluorosulfonic acid ionomer with hydrocarbon polyelectrolytes. Collectively, this review aims to provide a better understanding of factors that have hindered the transition from PFSA to non-PFSA based catalyst layers.

Alcohol-Soluble, Sulfonated Poly(arylene ether)s: Investigation of Hydrocarbon Ionomers for Proton Exchange Membrane Fuel Cell Catalyst Layers

“…This is in agreement with other studies of non-PFSA CLs in which electrodes are observed to densify as ionomer loading increases. 5 As a result of densification of the CL, electrode porosity is lost and mass transport resistances increase at high current densities. The particle size of the catalyst ink is observed to increase with 1 loading, with 20 and 30 wt% 1-containing inks being of similar particle size to Nafion-based inks.…”

“…However, while significant progress has been made studying HC solid polymer electrolytes as membranes, 4 there is very little understanding of their incorporation as ionomer in catalyst layers. 5 Studies on PFSA ionomer-based catalyst layers have revealed the complex nature of the interactions between ionomer, Pt, and the carbon support. [6][7][8] The agglomeration of PFSA ionomer in catalyst inks and during the catalyst layer deposition process are believed to dramatically affect proton, gas and water transport through the catalyst layer.…”

“…5 Studies on PFSA ionomer-based catalyst layers have revealed the complex nature of the interactions between ionomer, Pt, and the carbon support. [6][7][8] The agglomeration of PFSA ionomer in catalyst inks and during the catalyst layer deposition process are believed to dramatically affect proton, gas and water transport through the catalyst layer. A similar impact is expected for catalyst layers containing HC-based ionomers.…”

Poly(o-methoxyaniline) modified electrode for detection of lithium ions

“…8 Great advances have been made in recent years in the technological application of these materials for rechargeable batteries, electronic devices, thermal and chemical sensors, biosensors, smart windows etc. [9][10][11][12] An important point that should be considered when choosing a potentially conducting polymer is the ease with which the system can be oxidized or reduced without causing destabilization of the molecule, thereby giving preference to structures that have conjugated unsaturations (low oxidation potential), i.e. π electrons.…”

Conducting‐Polymer‐Based Materials for Electrochemical Energy Conversion and Storage

“…[24][25][26][27][28] Owing to their highly tunable conductivity, good electrocatalytic activity, and satisfactory electrochemical stability, conducting polymers are considered to be promising electrocatalyst materials for the ORR. [29] Initially, conducting-polymer-based electrodes were fabricated through direct casting of neutral To alleviate the current energy crisis and environmental pollution, sustainable and ecofriendly energy conversion and storage systems are urgently needed. Due to their high conductivity, promising catalytic activity, and excellent electrochemical properties, conducting polymers have been attracting intense attention for use in electrochemical energy conversion and storage.…”