Micro-porous patterning of the surface of a polymer electrolyte membrane by an accelerated plasma and its performance for direct methanol fuel cells

Mechanically Stable Thinned Membrane for a High-Performance Polymer Electrolyte Membrane Fuel Cell via a Plasma-Etching and Annealing Process

“…Nonetheless, the surface of E-N212 with a thickness of ∼25 μm was irregular and rugged, as seen in Figure b, which indicated that plasma treatment not only decreased membrane thickness but also modified the surface topography. Specifically, we observed that the root-mean-square (RMS) factor, which reflects the extent of surface roughness, increased dramatically from 1.61 to 331 nm and this is consistent with the previous plasma etching studies. − ,, To investigate the surface morphology change depending on the annealing temperature, we have varied annealing temperatures. It has been reported that the Nafion membrane has two kinds of glass transition temperatures ( T g ).…”

“…Specifically, we observed that the root-mean-square (RMS) factor, which reflects the extent of surface roughness, increased dramatically from 1.61 to 331 nm and this is consistent with the previous plasma etching studies. [14][15][16]27,28 To investigate the surface morphology change depending on the annealing temperature, we have varied annealing temperatures. It has been reported that the Nafion membrane has two kinds of glass transition temperatures (T g ).…”

High-Performance Fuel Cells with a Plasma-Etched Polymer Electrolyte Membrane with Microhole Arrays

“…Polymer electrolyte membrane fuel cells (PEMFCs) have attracted great attention as clean energy devices because of their high energy conversion efficiency with zero (harmful) emission , and diverse applications such as in stationary plants, portable devices, , and unmanned aerial vehicles in near future. , To successfully commercialize the PEMFC systems into the market, many researchers have tried to improve both their long-term durability and power density. − One of the effective ways for obtaining high-performance PEMFCs is engineering the interface between the catalyst layer (CL) and polymer electrolyte membrane (PEM), where the electrochemical reactions occur most effectively and the greatest number of active sites exists, via diverse approaches such as modification of the catalyst coating method, − optimization of ionomer and catalyst distribution, − and membrane modification. − In particular, applying appropriate patterning techniques for constructing micro/nanostructures at the interface between the PEM and the CL can enlarge the electrochemically active surface area (ECSA) and lead to enhancement of catalytic utilization and device performance. ,,, Furthermore, the patterned PEM can reduce the ohmic resistance because of the decrease of the membrane thickness as well as mass transport resistance because of generated void spaces between the CL and gas diffusion medium. ,, Based on these advantages, a lot of studies about PEM patterning in PEMFCs have been reported, and the patterning methods can be divided into three as follows: (a) casting an ionomer onto a patterned mold, , (b) thermal imprinting (or hot embossing) membranes with a hard structured mold, ,,, and (c) surface roughing through a plasma etching process. − In the case of the casting method, it has several disadvantages such as inapplicability for commercial PEMs and nonuniform thickness derived from the coffee-ring effect during solvent evaporation . When it comes to the hot embossing method, which is most commonly used, the process retains high structural fidelity using simple contact-based imprinting with a prefabricated hard master mold at the temperature above the glass transition temperature of the PEM. …”

“…Also, there are no restrictions on the contact-based method as mentioned above. However, most studies in the plasma etching method have mainly focused on increasing the nanosized roughness on the PEM surface. − The approach to enhance the overall PEMFC performance by increasing catalytic utilization and reducing ohmic and mass transport resistance via introducing well-defined etched microsized structures has not yet been conducted.…”

Surface modification of polyvinyl chloride by polyacrylic acid graftas a polyelectrolyte membrane using Ar plasma

“…Plasma has many benefits and it represents an advanced technique in PEM technology [5][6][7][8][9][10][11][12][13]. Inert plasma gases such as He, Ar, and N 2 are commonly used to improve the characteristics of surfaces [14][15][16][17][18].…”