고분자 전해질 연료전지 및 수전해용 촉매층의 이오노머 바인더

박종혁,마하무다아크테르,김범석,정다혜,이민영,신지윤,박진수,Park, Jong-Hyeok,Akter, Mahamuda,Kim, Beom-Seok,Jeong, Dahye,Lee, Minyoung,Shin, Jiyun,Park, Jin-Soo 한국전기화학회 2022 한국전기화학회지 Vol.25 No.4

Polymer electrolyte fuel cells and water electrolysis are attracting attention in terms of high energy density and high purity hydrogen production. The catalyst layer for the polymer electrolyte fuel cell and water electrolysis is a porous electrode composed of a precious metal-based electrocatalyst and an ionomer binder. Among them, the ionomer binder plays an important role in the formation of a three-dimensional network for ion conduction in the catalyst layer and the formation of pores for the movement of materials required or generated for the electrode reaction. In terms of the use of commercial perfluorinated ionomers, the content of the ionomer, the physical properties of the ionomer, and the type of the dispersing solvent system greatly determine the performance and durability of the catalyst layer. Until now, many studies have been reported on the method of using an ionomer for the catalyst layer for polymer electrolyte fuel cells. This review summarizes the research results on the use of ionomer binders in the fuel cell aspect reported so far, and aims to provide useful information for the research on the ionomer binder for the catalyst layer, which is one of the key elements of polymer electrolyte water electrolysis to accelerate the hydrogen economy era.

Design of an Advanced Membrane Electrode Assembly Employing a Double-Layered Cathode for a PEM Fuel Cell

Kim, GyeongHee,Eom, KwangSup,Kim, MinJoong,Yoo, Sung Jong,Jang, Jong Hyun,Kim, Hyoung-Juhn,Cho, EunAe American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.50

<P>The membrane electrolyte assembly (MEA) designed in this study utilizes a double-layered cathode: an inner catalyst layer prepared by a conventional decal transfer method and an outer catalyst layer directly coated on a gas diffusion layer. The double-layered structure was used to improve the interfacial contact between the catalyst layer and membrane, to increase catalyst utilization and to modify the removal of product water from the cathode. Based on a series of MEAs with double-layered cathodes with an overall Pt loading fixed at 0.4 mg cm<SUP>–2</SUP> and different ratios of inner-to-outer Pt loading, the MEA with an inner layer of 0.3 mg Pt cm<SUP>–2</SUP> and an outer layer of 0.1 mg Pt cm<SUP>–2</SUP> exhibited the best performance. This performance was better than that of the conventional single-layered electrode by 13.5% at a current density of 1.4 A cm<SUP>–2</SUP>.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-50/acsami.5b07346/production/images/medium/am-2015-07346t_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b07346'>ACS Electronic Supporting Info</A></P>

Deposition of Electrolyte for Intermediate Temperature Solid Oxide Fuel Cells by Combined Thin Film Deposition Techniques

하승범(Ha, Seungbum),지상훈(Jee, Sanghoon),와카스 하산 탄비르(Tanveer, Waqas Hassan),이윤호(Lee, Yoonho),차석원(Cha, Suk Won) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

Typical solid oxide fuel cells (SOFCs) have limited applications because they operate at high temperature due to low ionic conductivity of electrolyte. Thin film solid oxide fuel cell with yttria stabilized zirconia (YSZ) electrolyte is developed to decrease operating temperature. Pt/YSZ/Pt thin film SOFC was fabricated on anodic aluminum oxide (AAO). The crystalline structure of YSZ electrolyte by sputter is heavily depends on the roughness of porous Pt layer, which results in pinholes. To deposit YSZ electrolyte without pinholes and electrical shortage, it is necessary to deposit smoother and denser layer between Pt anode layer and YSZ layer by sputter. Atomic Layer Deposition (ALD) technique is used to deposit pre-YSZ layer, and it improved electrolyte quality. 300nm thick Bi-layered YSZ electrolyte was successfully deposited without electrical shortage.

Poly[(ethylene glycol) diacrylate]-Poly(vinylidene fluoride) 전해질을 이용한 전기 이중층 캐패시터의 전기화학적 특성

양천모 ( Chun Mo Yang ),이중기 ( Joong Kee Lee ),조원일 ( Won Il Cho ),조병원 ( Byung Won Cho ),주재백 ( Jeh Beck Ju ),유관표 ( Kwan Pyo Yoo ),임병오 ( Byung O Rim ) 한국공업화학회 2002 공업화학 Vol.13 No.8

자외선 경화법으로 제조한 PEGDA-PVdF 젤상 고분자 전해질을 전기이중층캐패시터에 적용하였고, 액상 유기 전해질을 이용한 전기이중층캐패시터와 전기화학적 특성을 비교 조사하였다. 자외선 경화법으로 제조된 젤상 고분자 전해질[GPE:poly[(ethylene glycol) diacrylate]-poly(vinylidene fluoride) blend]을 이용한 전기이중층캐패시터의 경우, 비축전용량이 120 F/g으로 액상 유기 전해질 [LOE:1 M LiPF_6/EC:DMC:EMC (1:1:1 volume ratio)]을 이용한 전기이중층캐패시터의 비축전용량인 110 F/g보다 우수하였고, 100회 충방전 후에도 초기 비축전용량대비 92% 이상 유지하는 우수한 싸이클 특성을 나타내었으며 3.7 Ω의 낮은 ESR(equivalent series resistance)을 보여주었다. Cyclic voltammetry 분석 결과에서 보면 액상 유기 전해질과 젤상 고분자 전해질을 이용한 모든 전기이중층캐패시터에서 2.5 V까지 전해질의 분해 없이 전기화학적으로 안정하였고, 산화와 환원과 관련된 전류값 또한 관찰되지 않았다. 젤상 고분자 전해질을 이용한 전기이중층캐패시터의 경우에서 직사각형 모양의 이상적인 전기이중층캐패시터의 특성과 49 ㎂의 낮은 누설 전류값을 나타내었다. 자가방전 특성 결과, 젤상 고분자 전해질을 이용한 전기이중층캐패시터의 경우 2.5 V의 정전압 충전 시 OCV(open circuit voltage) 상태에서 100 h 경과 후 1.76 V의 전압을 유지하고 있어 0.25 V의 액상 유기 전해질을 이용한 전기이중층캐패시터보다 매우 우수함을 확인하였다. Poly[(ethylene glycol) diacrylate] (PEGDA)-poly(vinylidene fluoride) (PVdF) gel polymer was employed as an electrolyte for electric double layer capacitor (EDLC) and compared its electrochemical characteristics with that of liquid organic electrolyte. The used organic electrolyte was 1 mole of lithium hexafluorophosphate (LiPF_6) salt containing in the solvent mixture of ethylene carbonate(EC):dimethyl carbonate(DMC):ethylmethyl carbonate(EMC)(1:1:1 volume ratio). The specific capacitance of EDLC with gel polymer electrolyte showed 120 F/g, which was superior to that of 110 F/g with liquid organic electrolyte. Good cyclability was observed for gel polymer electrolyte of EDLC. The 92% of initial specific capacitance was retained after 100 cycles of charge-discharge runs. Equivalent series resistance of 3.7 Ω of the EDLC with gel polymer electrolyte was lower than that of EDLC with liquid organic electrolyte. The EDLC with gel polymer electrolyte exhibited rectangular cyclic voltammogram of ideal EDLC in operating voltage range of 0∼2.5 V and low leakage current of 49 ㎂. Voltage drop from self-discharge was low for gel polymer electrolyte. The 29.6% of initial voltage decreased for gel polymer electrolyte, but significantly decreased to 99% for liquid organic electrolyte. The good retentivity with gel polymer electrolyte possible comes from the difference in viscosity compared with that of liquid organic electrolyte.

Morphology Engineering for Compact Electrolyte Layer of Solid Oxide Fuel Cell with Roll-to-Roll Eco-production

Minho Jo,Seongyong Kim,Changwoo Lee 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.2

Gadolinium-doped ceria (GDC) is sought-after as an electrolyte layer in solid oxide fuel cells because of its high ionic conductivity and low treatment temperature. Recently, some studies have been reported to produce a component layer of solid oxide fuel cell using a Roll-to-Roll (R2R) system because of its characteristics of the cost-effective and eco-friendly advantages. However, the brittleness and low density of GDC prevent it from being mass-produced via the R2R continuous process. Therefore, we attempted to improve the density of GDC-based multi-electrolyte layers through an optimized R2R calendaring process. The finite element method was employed to determine suitable materials for the calendering rolls and the maximum calendering pressure that would reduce the thickness and porosity of the coated electrolyte layer without producing cracks in the layer. The effect of the number of calendering processes on the thickness and porosity of the electrolyte layers was examined as well. Silicon and steel were observed to be best-suited as the materials for the top and bottom rolls, respectively. Moreover, the maximum permissible calendering pressure was determined to be 15 MPa, while the ideal number of calendering processes was found to be 5. Experimental observations using scanning electron microscopy confirmed that the optimized calendering process reduced the thickness and porosity of the coated electrolyte layers by 16.99% and 7.04%, respectively. Thus, our findings suggest that large-area, high-density GDC-based multi-electrolyte layers with smooth surfaces can be produced via the R2R process, which can enable mass production of SOFCs.

Fabrication of anode-supported protonic ceramic fuel cell with Ba(Zr_0.85Y_0.15)O_3-δ-Ba(Ce_0.9Y_0.1)O_3-δ dual-layer electrolyte

Choi, S.M.,Lee, J.H.,An, H.,Hong, J.,Kim, H.,Yoon, K.J.,Son, J.W.,Kim, B.K.,Lee, H.W.,Lee, J.H. Pergamon Press ; Elsevier Science Ltd 2014 International journal of hydrogen energy Vol.39 No.24

We fabricated a uniquely designed anode-supported-type protonic ceramic fuel cell (PCFC) with a dual-electrolyte layer containing BaCe<SUB>0.9</SUB>Y<SUB>0.1</SUB>O<SUB>3-δ</SUB> (BCY) as the higher-proton-conducting phase and BaZr<SUB>0.85</SUB>Y<SUB>0.15</SUB>O<SUB>3-δ</SUB> (BZY) as the chemically stable protecting phase. In order to overcome the poor sinterability of the BZY electrolytes, which is a critical limitation in making thin and dense dual-electrolyte layers for anode-supported PCFCs, we employed aid-assisted enhanced sintering of BZY by adding 1 mol% of CuO. We also promoted the densification of the BZY layer by utilizing the higher sinterability of BCY that is attached to the top of the BZY layer. By properly adjusting the shrinkage behaviors of both the anode substrate and the dual-electrolyte layers, we were able to fabricate a fairly dense BZY/BCY dual-layer electrolyte with a thickness of less than 20 μm. In this paper, the novel strategies used to fabricate the PCFC based on dual-electrolyte layers are reported.

Organic electrolyte hybridized ZnO as the electron transport layer for inverted polymer solar cells

Kim, Dong Geun,Kim, Youn Hwan,Maduwu, Ratna Dewi,Jin, Ho Cheol,Moon, Doo Kyung,Kim, Joo Hyun THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.65 No.-

<P><B>Abstract</B></P> <P>Small molecular organic electrolyte; <I>N</I>,<I>N</I>,<I>N</I>,<I>N</I>,<I>N</I>,<I>N</I>-hexakis(2-hydroxyethyl)butane-1,4-diaminium bromide (<B>C4</B>), doped ZnO is prepared by a typical sol–gel process and used as the for an electron transport layer in inverted polymer solar cells (PSCs). The electron mobility of the doped ZnO is comparable to that of pristine ZnO because the crystallinity of the ZnO layer is not significantly affected by the doping process. The Kelvin probe microscopy measurements employ that the work function of doped ZnO are −4.0eV, which is higher than that of pristine ZnO (−4.5eV). This is due to that the formation of interface dipole at the interface between the ZnO layer and the active layer by unreacted hydroxyl groups and quaternary ammonium bromide. As a result, inverted PSC based on <B>C4</B> doped ZnO exhibit the power conversion efficiency (PCE) up to 8.87%, which is a significant improvement over the device based on pristine ZnO (PCE=7.4%). Note that the main contribution to the enhancement of the PCE is from the improvement of the J<SUB>sc</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Small molecular organic electrolyte for dopant. </LI> <LI> Electrolyte doped ZnO a the electron transport layer. </LI> <LI> Enhancement of the PCE mainly resulted from the J<SUB>sc</SUB> improvement. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Fabrication and Characterization of Anode Supported YSZ/GDC Bilayer Electrolyte SOFC Using Dry Press Process

최훈,조구영,차석원 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.1 No.2

In the present paper, we fabricated and tested anode-supported solid oxide fuelcell(SOFC) with gadolinium-doped(GDC) and yttriastabilized zirconia (YSZ) electrolyte. The bilayer electrolyte thin film, consisting of a 8 μm thick YSZ layer and a 40 μm thick GDC layer, was prepared by a simple dry-pressing with simple spray coating process which is cost-effective method. The two electrolyte layers were sintered 1400oC together, and no crack and delamination at the interface were observed. An open-circuit voltage of 0.91 V and a maximum power density of over 218 mW/cm2 were measured with 3% H2O-H2 as fuel and air as oxidant at 600oC. The result shows that the electronic conductivity of GDC electrolyte was blocked by the thin YSZ electrolyte functional layer.

Characteristics of Oxide Layers Formed on Al2021 Alloys by Plasma Electrolytic Oxidation in Aluminate Fluorosilicate Electrolyte

Kai Wang,Bon Heun Koo,Chan Gyu Lee,Young Joo Kim,Sunghun Lee,Eungsun Byon 한국표면공학회 2008 한국표면공학회지 Vol.41 No.6

Oxide layers were prepared on Al2021 alloys substrate under a hybrid voltage of AC 200 V (60 ㎐) combined with DC 260 V value at room temperature within 5~60 min by plasma electrolytic oxidation (PEO). An optimized aluminate-fluorosilicate solution was used as the electrolytes. The surface morphology, thickness and composition of layers on Al2021 alloys at different reaction times were studied. The results showed that it is possible to generate oxide layers of good properties on Al2021 alloys in aluminate-fluorosilicate electrolytes. Analysis show that the double-layer structure oxide layers consist of different states such as α-Al₂O₃ and γ-Al₂O₃. For short treatment times, the formation process of oxide layers follows a linear kinetics, while for longer times the formation process slows down and becomes a steady stage. During the PEO processes, the average size of the discharge channels increased gradually as the PEO treatment time increased.

Performance Enhancement of Polymer Electrolyte Membrane Fuel Cell in Dry Operation via Carbon Nanotube-based Nanoporous Layer

J. Kim(김재연),T. Park(박태현) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월

Carbon nanotubes (CNT) based nanoporous layer in polymer electrolyte membrane fuel cells (PEMFCs) is investigated. CNT sheet are prepared via direct spinning method, and its thickness is 15 μm. The nanoporous layer is employed as either single layer or as an additional layer with carbon-black microporous layer (MPL), and they contact catalyst layer of PEMFC. For ex-situ investigation of MPL and CNT, scanning electron microscopy (SEM), sessile drop technique, raman spectroscopy, and image thresholding are employed. SEM result shows fine-fibrous pore architecture of CNT, and it is differentiated from that of MPL. For in-situ electrochemical methods, current density-voltage polarization curve and electrochemical impedance spectroscopy are utilized. The best performance is obtained when CNT is employed as an additional nanoporous layer with MPL. Improvements in comprehensive water management and reaction kinetics lead to this enhancement. In particular, the enhanced water management, i.e., water storage and expulsion behaviors, is the benefits differentiated from the single nanoporous layer.