scholarly journals Graphite/epoxy composite for building Bipolar Plates

2022 ◽  
Vol 334 ◽  
pp. 04010
Author(s):  
Luca Spinelli ◽  
Fabrizio Roncaglia ◽  
Roberto Biagi ◽  
Alessandro di Bona ◽  
Marcello Romagnoli ◽  
...  

Bipolar plates (BPs) are important components of Proton Exchange Membrane Fuel Cells (PEMFC). Graphite-epoxy composites, having a better corrosion resistance than metal-based BPs and better mechanical properties than graphite BPs, are a promising alternative. In this study, we tried to develop graphite-epoxy composites meeting the technical US DOE targets for 2020, with a proper choice of manufacturing conditions that ensure a good compromise between conductivity, flexural strength, and gas permeability. In particular, we studied the influence of the filler to binder ratio, changed the molding temperature and time, and investigated the effects of increasing pressure both on in-plane conductivity and on helium permeability. We found that both formulation and molding pressure are crucial in determining the permeability of the graphite-epoxy composites, whereas molding temperature and time seem to play a minor role.

Author(s):  
Frej Mighri ◽  
Luc Nguyen

This research work aimed at developing, by twinscrew extrusion process, electrically conductive sheets for proton exchange membrane fuel cell (PEMFC) bipolar plates. For this, a series of highly conductive blends were carefully formulated from a co-continuous mixture of polythylene terephthalate (PET)/polyvinylidene fluoride (PVDF) and high specific surface area carbon black (CB) and graphite (GR) conductive additives. Several major factors, such as CB/GR content, PVDF/PET composition and morphology, and also PET crystallinity were shown to have remarkable effects on these three main properties.


2021 ◽  
Vol 262 ◽  
pp. 113617
Author(s):  
Kwang Il Jeong ◽  
Jaehyung Oh ◽  
Seung A Song ◽  
Dongyoung Lee ◽  
Dai Gil Lee ◽  
...  

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 437
Author(s):  
Yi Liu ◽  
Luofu Min ◽  
Wen Zhang ◽  
Yuxin Wang

In this article, we proposed a facile method to electrophoretically deposit a highly conductive and corrosion-resistant graphene layer on metal bipolar plates (BPs) while avoiding the oxidation of the metal substrate during the electrophoretic deposition (EPD). p-Phenylenediamine (PPD) was first grafted onto negatively charged graphene oxide (GO) to obtain modified graphene oxide (MGO) while bearing positive charges. Then, MGO dispersed in ethanol was coated on titanium plates via cathodic EPD under a constant voltage, followed by reducing the deposited MGO with H2 at 400 °C, gaining a titanium plate coated with reduced MGO (RMGO@Ti). Under the simulated environment of proton exchange membrane fuel cells (PEMFCs), RMGO@Ti presents a corrosion current of < 10−6 A·cm−2, approximately two orders of magnitude lower than that of bare titanium. Furthermore, the interfacial contact resistance (ICR) of RMGO@Ti is as low as 4 mΩ·cm2, which is about one-thirtieth that of bare titanium. Therefore, RMGO@Ti appears very promising for use as BP in PEMFCs.


2010 ◽  
Vol 160-162 ◽  
pp. 1469-1475
Author(s):  
Nai Bao Huang ◽  
Cheng Hao Liang ◽  
Guo Qiang Lin ◽  
Li Shuang Xu ◽  
Bao Lian Li

By using electrochemical techniques, the electrochemical characteristic of Cr-based film coated 304 stainless steel (304SS) as proton exchange membrane fuel cell (PEMFC) bipolar plates, which was deposited by cathodic arc deposition technology, was studied. The results indicated that Cr, CrN, (TiCr)N and (TiN+Ti) film could not only decreased the steel’s contact resistance but also improved its corrosion resistance and the fuel cell stack’s performance. Since Cr, (CrN) and (TiCrN) film were more compact than (TiN+Ti) film, which contained the oxides of Ti, as bipolar plates, the performance for all film change in the following order: Cr film ≈(CrN) film ≈ (TiCrN) film >(TiN+Ti) film.


Author(s):  
Jingkun Li ◽  
Moulay-Tahar Sougrati ◽  
andrea Zitolo ◽  
James Ablett ◽  
ismail can oguz ◽  
...  

While Fe-N-C materials are a promising alternative to platinum for catalyzing oxygen reduction in acidic polymer fuel cells, limited understanding of their operando degradation restricts rational approaches towards improved durability. Here we show that Fe-N-C catalysts initially comprising two distinct FeNx sites (S1 and S2) degrade via the transformation of S1 into iron oxides while the structure and number of S2 were unmodified. Structure-activity correlations drawn from end-of-test 57Fe Mössbauer spectroscopy reveal that both sites initially contribute to the ORR activity but only S2 significantly contributes after 50 h of operation. From in situ 57Fe Mössbauer spectroscopy in inert gas coupled to calculations of the Mössbauer signature of FeNx moieties in different electronic states, we identify S1 to be a high-spin FeN4C12 moiety and S2 a low- or intermediate spin FeN4C10 moiety. These insights lay the ground for rational approaches towards Fe-N-C cathodes with improved durability in acidic fuel cells.<br>


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