Layer-by-Layer Polydimethylsiloxane Modification Using a Two-Nozzle Spray Process for High Durability of the Cathode Catalyst in Proton-Exchange Membrane Fuel Cells

Abstract

The catalyst layer’s high durability is essential in commercializing polymer electrolyte membrane fuel cells (PEMFCs), particularly for vehicle applications, because their frequent on/off operation can induce carbon corrosion, which affects surface properties and morphological characteristics of the carbon and results in aggregation and detachment of Pt nanoparticles on the carbon surface. Herein, to address the carbon corrosion problem while delivering a high-performance PEMFC, polydimethylsiloxane (PDMS) with high gas permeability, chemical stability, and hydrophobicity was employed to protect the catalyst layer from carbon corrosion and improve the mass transport. Because the catalyst slurry using alcohol-based solvents showed low compatibility with nonpolar solvents of the PDMS solution, a parallel two-nozzle system with separated solution reservoirs was developed by modifying a conventional three-dimensional printing machine. To determine the optimal PDMS amount in the cathode catalyst layer, PDMS solution concentration was varied by quantitatively controlling the PDMS amount coated on the electrode layer. Finally, the PEMFC with the PDMS-modified cathode of 0.1 mgPDMS cm–2 loading showed enhanced durability due to increased electrochemical surface and maximum power density by 37.2 and 21.7%, respectively, after the accelerated stress test. Furthermore, an improvement in the initial performance from enhanced water management was observed compared to those of PEMFCs with a conventional electrode.

Nanoarchitectonics and electrocatalytic properties of platinum nanoparticles in weak polyelectrolytes‐based multilayer thin films

“…The EASA of both multilayer thin films decreased between −0.2 and 0.8 V under 1000 potential cycles, while there was no discernible structural change in surface structure during extended cycles (Figure S5 and S6). Although the electrocatalytic performances of polymer composites assembled via the LbL method have been widely studied, relatively little work has been performed to investigate the effect of structural changes on electrochemical behaviors using LbL assembly 48–50 . The present study is the first to demonstrate that the electrocatalytic activity of Pt NPs can be controlled by the conformational variations of weak polyelectrolytes.…”

“…Although the electrocatalytic performances of polymer composites assembled via the LbL method have been widely studied, relatively little work has been performed to investigate the effect of structural changes on electrochemical behaviors using LbL assembly. [48][49][50] The present study is the first to demonstrate that the electrocatalytic activity of Pt NPs can be controlled by the conformational variations of weak polyelectrolytes. Altering the deposition pH of the various layers results in different physical and structural properties, which consequently affect catalytic activities.…”

Optimized mass transfer in a Pt-based cathode catalyst layer for PEM fuel cells

“…Similarly, a novel two-nozzle spray system has been explored using polydimethylsiloxane with high gas permeability, hydrophobicity, and chemical stability to address the water management problem while delivering a high-performance PEMFC. 94 The manufactured CCL eliminated the reaction product water, improved mass transmission, and performed well without carbon corrosion.…”

Controllable construction of Pt/CNT catalyst layers to improve Pt utilization in PEMFCs

“…To address the predicaments confronting PEMFCs, extensive work has focused on investigating the catalyst layer (CL) and catalyst structure of the membrane electrode assembly (MEA). [5][6][7] The CL, where the electrochemical reaction occurs, is considered the core component of fuel cells, dominating the electrochemical reaction rate and mass transfer efficiency, thereby seriously affecting the fuel cell performance. [8][9][10] To promote fuel cell performance and improve the catalyst utilization rate, the orientated CL structure has been proposed and signicant progress has been made based on different materials, including Pt nanowire arrays, 11,12 carbon nanotube (CNT) arrays, 2,13,14 metal oxide nanorod arrays, [15][16][17] etc., providing ordered electron, proton, and gas transport channels, to reduce mass transfer resistance and avoid water ooding.…”