Interface engineering for high-performance direct methanol fuel cells using multiscale patterned membranes and guided metal cracked layers

Jang, Segeun; Kim, Sungjun; Kim, Sang Moon; Choi, Jiwoo; Yeon, Jehyeon; Bang, Kijoon; Ahn, Chi‐Yeong; Hwang, Wooncheol; Her, Min; Cho, Yong‐Hun; Sung, Yung‐Eun; Choi, Mansoo

doi:10.1016/j.nanoen.2017.11.011

Cited by 33 publications

(18 citation statements)

References 30 publications

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“…Furthermore, metal oxides such as TiO 2 , WO 3 and NbO 2 can reportedly replace carbon carriers in which the design principle of the interface between the CL and the membrane is to increase adhesion and therefore improve cell durability. Other studies have also focused on CL designs [157] based on the shape of flow fields [158,159]. More significantly, Giner ELX Inc. was able to enhance catalytic performances by threefolds at 1000 mA cm −2 (Fig.…”

Section: Electrocatalysts and Catalyst Layersmentioning

confidence: 99%

Electrochemical Compression Technologies for High-Pressure Hydrogen: Current Status, Challenges and Perspective

Zou

Han

Yan

et al. 2020

Electrochem. Energ. Rev.

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Hydrogen is an ideal energy carrier in future applications due to clean byproducts and high efficiency. However, many challenges remain in the application of hydrogen, including hydrogen production, delivery, storage and conversion. In terms of hydrogen storage, two compression modes (mechanical and non-mechanical compressors) are generally used to increase volume density in which mechanical compressors with several classifications including reciprocating piston compressors, hydrogen diaphragm compressors and ionic liquid compressors produce significant noise and vibration and are expensive and inefficient. Alternatively, non-mechanical compressors are faced with issues involving large-volume requirements, slow reaction kinetics and the need for special thermal control systems, all of which limit large-scale development. As a result, modular, safe, inexpensive and efficient methods for hydrogen storage are urgently needed. And because electrochemical hydrogen compressors (EHCs) are modular, highly efficient and possess hydrogen purification functions with no moving parts, they are becoming increasingly prominent. Based on all of this and for the first time, this review will provide an overview of various hydrogen compression technologies and discuss corresponding structures, principles, advantages and limitations. This review will also comprehensively present the recent progress and existing issues of EHCs and future hydrogen compression techniques as well as corresponding containment membranes, catalysts, gas diffusion layers and flow fields. Furthermore, engineering perspectives are discussed to further enhance the performance of EHCs in terms of the thermal management, water management and the testing protocol of EHC stacks. Overall, the deeper understanding of potential relationships between performance and component design in EHCs as presented in this review can guide the future development of anticipated EHCs.

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Section: Electrocatalysts and Catalyst Layersmentioning

confidence: 99%

Electrochemical Compression Technologies for High-Pressure Hydrogen: Current Status, Challenges and Perspective

Zou

Han

Yan

et al. 2020

Electrochem. Energ. Rev.

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“…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. …”

Section: Introductionmentioning

confidence: 99%

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

Seol

Jang

Lee

et al. 2021

ACS Sustainable Chem. Eng.

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Interface engineering based on the design and fabrication of micro/nanostructures has received much attention as an effective way to improve the performance of polymer electrolyte membrane (PEM) fuel cells while using the same materials and quantity. Herein, we fabricated spatially hole-array patterned PEMs with different hole depths using both the plasma etching process and a polymeric stencil with 40 μm-sized apertures. This novel technological approach exhibited high pattern fidelity over a large area and controllability in the pattern depth while excluding the problems of contact-based conventional patterning processes. All the membrane electrode assemblies (MEAs) with the patterned PEMs with an etch depth of 4 μm (PE4-MEA), 8 μm (PE8-MEA), and 12 μm (PE12-MEA) showed higher performance than the reference MEA with a pristine PEM. Among the modified MEAs, the PE8-MEA showed the highest performance enhancement because of the locally thinning effect of the PEM, geometrically favorable features for mass transport, and increased interfacial contact area between the PEM and the catalyst layer.

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“…By utilizing these intriguing properties of each nano‐ and microstructures simultaneously, multiscale hierarchical structures can provide multifunctional effects to the system and maximize their function without the need for any further physicochemical processes. Thus, there have been many attempts to use multiscale hierarchical structures in diverse fields and applications, including micro/nanofluidics, wearable devices, optical devices, and energy systems with various materials including polymers, metals, and ceramics …”

Section: Introductionmentioning

confidence: 99%

Multiscale Hierarchical Patterning by Sacrificial Layer‐Assisted Creep Lithography

Jang

Choi

Shin

et al. 2019

Adv Materials Inter

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to the expectation that technological breakthroughs can be achieved. [1][2][3] As is well known in literature, nanostructures exhibit unique properties such as plasmonic effects, [4] antireflection, [5] structural color, [6] super-hydrophobicity, [7] adhesion, [8] superior catalytic activity, [9] and charge transport. [10] Microstructures lend mechanical properties (e.g., stress-strain relationship, hardness, and flexibility) [7] to the system and enable the control of light, liquid, and gas pathways. [11][12][13][14] By utilizing these intriguing properties of each nanoand microstructures simultaneously, multi scale hierarchical structures can provide multifunctional effects to the system and maximize their function without the need for any further physicochemical processes. Thus, there have been many attempts to use multiscale hierarchical structures in diverse fields and applications, including micro/nanofluidics, [15] wearable devices, [16] optical devices, [17,18] and energy systems [19,20] with various materials including polymers, metals, and ceramics. [21,22] Our recent study showed that multiscale hierarchical structure can be simply and easily fabricated with the aid of creep behavior of a polymer, [23] which is a permanent deformation of the material due to the viscoelastic behavior of the polymer under long-term stress below the glass transition temperature. In this work, nanostructures were first carved onto polymer films by hot-embossing nanoimprint lithography (NIL) and then followed by a second imprinting with a micropattern mold using the creep deformation characteristic of the polymer film. This facile multiscale patterning method does not require any sophisticated process and equipment. Further, by using Nafion as a substrate that has a low modulus (≈250 MPa) and large creep deformation property, [24,25] we can use diverse polymeric molds instead of metallic molds that require very high pressures for conformal contact with the substrate. However, this method had a weakness that previously carved nanostructures also inevitably underwent creep deformation during the second imprinting process, which led to deformation of the original morphologies of the nanostructures.To address this issue, we introduced a poly(methyl methacrylate) (PMMA) sacrificial layer to protect the preformed structures before the secondary creep-based imprinting process. The PMMA sacrificial layer has a larger modulus (≈3 GPa) [26] The capability to fabricate various multiscale structures without limitations of size, morphology, and number of hierarchies via a simple process is highly desired in modern research. This work reports a powerful multiscalepatterning method called sacrificial layer-assisted creep lithography (SCL). Multiscale structures are successfully obtained by introducing a sacrificial layer, which has low creep compliance and preferential solubility in a nonpolar solvent, on a Nafion film during an additional creep-based imprinting process. Through this method, deformation or geometrical loss of preformed st...

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Interface engineering for high-performance direct methanol fuel cells using multiscale patterned membranes and guided metal cracked layers

Cited by 33 publications

References 30 publications

Electrochemical Compression Technologies for High-Pressure Hydrogen: Current Status, Challenges and Perspective

Electrochemical Compression Technologies for High-Pressure Hydrogen: Current Status, Challenges and Perspective

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

Multiscale Hierarchical Patterning by Sacrificial Layer‐Assisted Creep Lithography

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