Interfacial Contact Resistance Research Articles

Corrosion resistance and conductivity of CrN, CrAlN, and CrTiN coatings applied to bipolar plates for proton exchange membrane fuel cells

In order to improve the corrosion resistance and conductivity of 316L stainless steel bipolar plates used for proton exchange membrane fuel cells, three Cr-containing nitride coatings were deposited on 316L stainless steel by multiarc ion plating. First, the microstructure, composition, and contact angle of the three coatings were systematically investigated. Then, electrochemical impedance spectroscopy, potentiodynamic polarization, potentiostatic polarization (PSP), and interfacial contact resistance (ICR) of the three coatings were also fully examined. The results revealed that CrN coating has the highest contact angle of 98.26°, indicating its superior hydrophobicity. Additionally, CrN coating performed the best corrosion resistance with the highest corrosion potential of 0.31 V, the lowest corrosion current density of 2.28 × 10−7 A cm−2, and the largest resistance. Furthermore, CrN coating showed the lowest current density during PSP tests and the smallest ICR value after corrosion. The superior corrosion resistance of CrN coating is mainly attributed to its decreased pore density caused by vacancylike defects and its uniform structure. This article provided evidence for the potential application of CrN coating to bipolar plates.

Soldering Pressure Effect on Lifetime of Thermoelectric Modules under Thermal Cycling.

For practical industrial applications, enhancing the longevity and the reliability of thermoelectric modules (TEMs) is equally as crucial as improving their conversion efficiency. This study proposes a strategy for extending the lifespan and introduces the quality evaluation criteria for the most extensively used commercial bismuth telluride TEM. By varying the soldering pressure during module assembly, its impact on the quality of the module's internal interfacial connections was investigated, via analyzing its contact resistivity, shear modulus, and antifatigue ability through thermal cycling tests. The findings reveal that increasing the soldering pressure leads to a slight reduction in interfacial contact resistivity and has no significant effect on the shear modulus but notably enhances the module's antifatigue ability during thermal cycling tests. According to the SEM results, it can be evidently deduced that the aforementioned phenomena are directly correlated with the size and quantity of voids distributed in the solder layer, which is regarded as the origin of antifatigue ability. Thus, it can be inferred that augmenting the soldering pressure represents an effective approach to prolonging the lifespan of TEMs assembled by using the soldering method. Furthermore, the existence of voids within the solder layer can serve as a criterion for an initial assessment of module longevity. This study provides a reference for both the industrial assembly and lifespan evaluation of commercial bismuth telluride TEMs.

Ex-situ Characterization of Nb-Ti Alloy/Pt Coated Stainless Steel Bipolar Plates for Proton Exchange Membrane Fuel Cells

Metallic bipolar plates are crucial for the development of compact and lightweight proton exchange membrane fuel cell stacks; however, most of them encounter durability and conductivity challenges in the fuel cell environment. In this study, Nb-Ti alloy/Pt coatings are deposited on SS316L plates to enhance corrosion resistance, surface wettability, electrical and thermal conductivity, with reduced interfacial contact resistance. Corrosion resistance is assessed by exposing test samples to a 1M H2SO4 acidic environment at 25 °C and 80 °C, respectively, via potentiostatic and potentiodynamic polarization tests. It is found that Nb-Ti alloy/Pt coatings exhibit exceptional stability, with corrosion potential increased by 2.5 (at 25 °C) and 0.5 (at 80 °C) times and corrosion current density reduced by orders of magnitude; and their anti-corrosion performance far exceeds the technical targets set by the US Department of Energy, with a protective efficiency of 99.98 % at both temperatures tested. The coated samples have reduced water affinity, indicated by significantly larger contact angle values compared to the uncoated samples in both pre-and post-corrosion tests. The incorporation of Nb-Ti alloy/Pt coatings on SS316L increases the in-plane electrical conductivity by 42.6 % and thermal conductivity by 3.5 %; surpassing the US Department of Energy's technical targets in these categories as well. At a compaction force of 140 N/cm2, the interfacial contact resistance for the coated samples is about 2.5 times lower than the Department of Energy's requirements. These results indicate the viability of Nb-Ti alloy/Pt coated SS316L bipolar plates for fuel cell applications.

A comparative study of streamlined flow channels with water drop block configurations and their effects on temperature profiles, mass transport characteristics, and performance in PEM fuel cell

The problems of temperature distribution, mass transport, and drainage performance in flow field channels (FFCs) become the most significant effects on PEMFC performance. In order to solve the above problems, this study proposes five distinct streamlined block architectures of flow channels that consider interface contact resistance (ICR) and gas diffusion layer (GDL) face permeability effect on temperature profiles to enhance mass transport and cell performance of PEMFC. The streamlined block structures of flow channels considering ICR and GDL face permeability were comparatively evaluated. The results show that the temperature profiles exhibit a distinctive "Ʌ" shape with an approximate increase of 0.19ᵒC at CN 2 compared to CN1. Besides, CN6 has current density, power density, and the best removal water saturation of 6.94%, 12.27%, and 7.18%, respectively, are higher than CN1 (conventional model) when the voltage is 0.4 V. Consequently, the streamlined imitated water-drop block (WDB) models applied in the flow channels with considering both suitable ICR and GDL face permeability for PEM fuel cell can improve the mass transport capacity, enhance the speed of the electrochemical reaction, and provide better cell performance.

Investigation of Cu-doped amorphous carbon film in improving corrosion resistance and interfacial conductivity of proton exchange membrane fuel cell

This study investigated Cu-doped a-C films prepared under a substrate bias gradually reducing from 120 to 60 V and different Cu target currents of 0, 0.15, 0.2, 0.3, 0.5 A, respectively, using closed field unbalanced magnetron sputtering physical vapour deposition technique. While the Cu-doped a-C film at the lowest Cu target current of 0.15 A (A0.15) remained an amorphous microstructure, Cu nanoprecipitates occurred at Cu target currents of 0.2–0.5 A. All the Cu-doped a-C films prepared exhibited good combination of corrosion resistance to a corrosive chemical mixture of 0.5 M H2SO4 + 5 ppm HF (as suggested by the corrosion current densities) and interfacial electric conductivity (as demonstrated by the interfacial contact resistance, ICR). Among all coatings, A0.15 showed the best corrosion resistance and interfacial electric conductivity, which is attributable to the precipitate-free Cu-doped amorphous microstructure. The measured current density of A0.15 was 1.95 × 10−7 A/cm2 at 0.6 V (vs. SCE) during potentiodynamic polarization, which was lower than that of the Cu-free a-C film at 7.34 × 10−7 A/cm2. The ICR value of A0.15 was 4.40 mΩcm2 at an assembly pressure of 1.4 MPa, which is about one third of the Cu-free a-C film. This study demonstrates a new deposition strategy combining Cu-doping and the control of substrate bias to improve the corrosion resistance and interfacial electric conductivity of a-C films for PEMFC.

Alternating C- and Ti-dominated sublayers on bipolar plates achieve enhanced corrosion resistance under high potentials toward proton exchange membrane fuel cells

High cathodic transient potentials accelerate the dissolution of metal bipolar plates, and developing corrosion-resistant coatings is imperative. A multilayer coating that C and Ti alternatively dominated the sublayers is fabricated on SS316L (C/Ti/SS). Such an optimized composition and structure significantly expands transpassive potential to 1.6V and thus offers full protection within the entire working potential range of proton exchange membrane fuel cells. After 10000 cyclic polarizations with Epeak of 1.6V, a conductive TiO2 nanofilm forms on the surface and C/Ti/SS achieves a noticeable interfacial contact resistance of 9.43 mΩ∙cm2, highlighting the remarkable commercial application of the novel coating.

Corrosion Resistance and Conductivity of Ta-Nb-N-Coated 316L Stainless Steel as Bipolar Plates for Proton Exchange Membrane Fuel Cells

The large-scale application of stainless steel (SS) bipolar plates (BPs) in proton exchange membrane fuel cells (PEMFCs) is mainly limited by insufficient corrosion resistance and electrical conductivity. In this work, Ta-Nb-N coatings were prepared on 316L SS substrates by unbalanced magnetron sputtering to improve corrosion resistance and conductivity. The Ta-Nb-N coatings had a dense structure without obvious defects. In simulated PEMFC cathode environments consisting of 0.5 M H2SO4 + 2 ppm HF at 70 ± 0.5 °C, which is harsher than the U.S. Department of Energy specification, the corrosion current density of Ta-Nb-N-coated BPs was reduced to 2.2 × 10−2 μA·cm−2. Ta-Nb-N-coated samples showed better electrical conductivity than 316L SS, which had an excellent interfacial contact resistance of 9.2 mΩ·cm2. In addition, the Ta-Nb-N-coated samples had a water contact angle of 100.7°, showing good hydrophobicity for water management. These results indicate that Ta-Nb-N coatings could be a promising material for BPs.

Cathode Catalyst Layer Design in PEM Water Electrolysis toward Reduced Pt Loading and Hydrogen Crossover.

Reducing the use of platinum group metals is crucial for the large-scale deployment of proton exchange membrane (PEM) water electrolysis systems. The optimization of the cathode catalyst layer and decrease of the cathode Pt loading are usually overlooked due to the predominant focus of research on the anode. However, given the close relationship between the rate of hydrogen permeation through the membrane in an operating cell and the local hydrogen concentration near the membrane-cathode interface, the structural design of the cathode catalyst layer is considered to be of pivotal importance for reducing H2 crossover, particularly in combination with the use of thin (≲50 μm) membranes. In this study, we have conducted a detailed investigation on the cathode structural parameters, covering the Pt wt % of the Pt/C electrocatalyst, the type of carbon support (Vulcan and high surface area carbon, HSAC), and the ionomer content, with a goal to reduce Pt loading to 0.025 mgPt/cm2 while minimizing the rate of cell hydrogen crossover. We found that the electrochemical performance is mainly influenced by the changes in the interfacial contact resistance due to variations in the cathode thickness. Both the Pt wt % in Pt/C and the ionomer content showed a positive correlation with the measured H2 in O2% in the anode outlet, whereas the Pt loading exhibited an opposite trend. The rate of hydrogen crossover was analyzed in relation to the calculated local volumetric current density within the cathode catalyst layer. Based on the obtained hydrogen mass transfer coefficient, a cathode catalyst layer comprising 40 wt % Pt on HSAC support with an ionomer-to-carbon (I/C) ratio of 0.35 was found to be an optimum configuration for achieving a low Pt loading of 0.025 mgPt/cm2 and a reduced rate of hydrogen crossover.

Effect of magnetron sputtering C-doped CrN film on the conductivity and corrosion resistance of 304 stainless steel bipolar plates

Using a high-power impulse and direct current (DC) magnetron sputtering approach, C-doped CrN films with various C-target pulse frequencies are created on the surface of SS 304. The microstructure, corrosion resistance and conductivity of the films are examined. With the decreases of C-target pulse frequency, the roughness of the CrCN films decreases and the density increases. The results of XPS and TEM analyses demonstrate that C atoms are either present in CrN lattice as interstitial atoms or precipitate at grain boundaries to form amorphous carbon, which facilitates the increase of film density and conductivity. In the potentiodynamic tests, the CrCN-1000 Hz film exhibits the lowest corrosion current density 0.54 μA/cm2 at 0.6 V vs. Ag/AgCl potential. The values of icorr and Ecorr are 0.11 μA/cm2 and 0.427 V, respectively. Furthermore, the CrCN-1000 Hz film has the lowest interface contact resistance (ICR) under a compaction force of 140 N/cm2 after potentiostatic polarization test, indicating that C doping is beneficial to improve the corrosion resistance and conductivity of CrN film.

Temperature-relevant degradation in amorphous carbon coated SS316L bipolar plates for PEMFC

The corrosion of metallic Bipolar Plates (BPs) has become a key bottleneck in the practical application of proton exchange membrane fuel cells (PEMFCs). Environmental factors inside the PEMFCs significantly accelerate the degradation of electrical conductivity and durability of metallic BPs. In this work, we investigated the corrosion behavior and conductive properties of amorphous carbon coating (a-C) coated SS316L in a simulated PEMFC environment at various operating temperatures. The results showed that the corrosion current density (Icorr) of a-C varied in a range of 2.3–8.7 nA/cm2 when subjected to a temperature range of 40–80 °C. Additionally, the interfacial contact resistance increased from 4.36 to 9.56 mΩ/cm2 with a rise in temperature. The reasons could be ascribed to two aspects. First, the a-C maintained the good chemical stability of sp2/sp3 bonds regardless of temperature changes, favoring remarkable anti-corrosion and good conductivity. Second, the higher temperatures intensified the penetration of corrosive species, accelerating the dissolution process of a-C coated SS316L and leading to substantial corrosion failure.

Metallic barrier layer for Ag2S1−xSex inorganic ductile thermoelectric materials

Metallic barrier layer is a key component in thermoelectric (TE) devices, but it is rarely investigated for the recently discovered inorganic ductile TE materials. In this work, we demonstrate that tungsten (W) is the excellent metallic barrier layer for Ag2S1−xSex ductile thermoelectric materials. The phase composition, microstructure, adhesive strength, and interfacial contact resistivity (ρC) of the W/Ag2S1−xSex joint have been systematically investigated. The sputtered W film has high adhesive strength and little interdiffusion/reaction with Ag2S1−xSex. The ρC decreases with increasing the Se content, which can be understood by the Thermionic-field Emission model. This work would guide the development of high-performance flexible TE devices based on ductile TE materials.

Investigation of evolution of γ N phase and its effect on conductivity and corrosion resistance of plasma-nitrided 316 L stainless steel bipolar plate for proton exchange membrane fuel cell

In this work, the evolution of γ N phase and its effect on conductivity and corrosion resistance of plasma-nitrided 316 L stainless steel bipolar plate was investigated. The results shows that a certain thickness of uniform γ N phase layer was formed after plasma-nitriding treatment. As the increasing in plasma-nitriding time, the thickness of γ N phase layer and nitrogen atoms in γ N phase layer was increased gradually. As the plasma-nitriding time was larger than 10 h, a large amount of cracks was formed in γ N phase layer because the nitrogen atoms were diffused into γ phase to cause the serious lattice distortion. When the plasma-nitriding time was reached to 24 h, the Fe4N compound was found on the sample surface. After plasma-nitriding treatment, the conductivity and corrosion resistance of the sample was obviously enhanced compared with the untreated sample. With the increasing in the thickness of γ N phase layer, the interfacial contact resistance (ICR) and corrosion current of the sample was gradually reduced. The ICR of the sample was reduced to 7 mΩ under 10 h condition. However, the formation of Fe4N compound and high roughness contributed to the increase of ICR of the sample under 24 h condition, its value was reached to 15 mΩ. When the plasma-nitriding time was larger than 10 h, the corrosion resistance of the sample became poor. The formation of cracks in γ N phase layer and the high surface roughness resulted in the degradation of corrosion resistance of the sample. Under 5 h condition, the comprehensive properties of the sample were the best. The ICR and corrosion of the sample were current conductivity and corrosion resistance of the sample were 15 mΩ and 5.1 μA cm−2, which were low 4 times and 15 times compared with the untreated sample.

Corrosion behavior and surface structure analysis of pure aluminum immersed in fluoride‐sulfate solutions simulating polymer electrolyte membrane fuel cell‐produced water

AbstractBipolar plates are the key component in polymer electrolyte membrane fuel cells (PEMFCs), which ensure the low cost of the fuel cell stack and furnish some of the important applications such as distributing the reactant gases, conducting the electrons, and removing the waste heat in PEMFCs. Thus, metallic bipolar plates (BPs), such as aluminum (Al), have attracted immense consideration and afford better performance in different machine‐driven applications and mass manufacturing opportunities. In order to increase the corrosion resistance of Al BPs, several methods are used and conducted by scientists. The corrosion behavior and surface structure analysis of pure Al were studied through the immersion process in fluoride‐sulfate solutions, assuming its use as BPs in PEMFC‐produced water. The open cell voltage, interfacial contact resistance, and polarization tests and the fuel cell operations were performed to evaluate cell voltage, current density, corrosion resistance, and the effect of fluoride and sulfate ions on the BPs in PEMFC. The hydrophobicity character of the surface of Al BPs was observed by the measurement of the wettability test. The atomic force microscopy images were taken to study the surface roughness, which was correlated with the corrosion rates of Al BPs. In addition, the amount of corrosion was calculated after 24–120 h of immersion in fluoride‐sulfate solutions. The scanning electron microscopy, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy data were analyzed to investigate the surface structure, morphology, and elemental analyses. Thus, the results found in this study revealed that Al‐based materials can be suitable for BPs in PEMFCs. Furthermore, it is noticed that the amount of corrosion was influenced by the presence of even a very small amount of fluoride ions present in the PEMFC environment, while it was suppressed efficiently by sulfate ions.

Performance of Stainless-Steel Bipolar Plates (SS-BPPs) in Polymer Electrolyte Membrane Water Electrolyser (PEMWE): A Comprehensive Review

Bipolar Plates (BPPs) play a critical role in Polymer Electrolyte Membrane Water Electrolysers (PEMWEs) for effective hydrogen generation. The performance and longevity of the system can be considerably impacted by choosing the suitable material for these components. Polymer electrolyte membrane water electrolysis technology relies on cost-effective and corrosion-resistant BPPs. Tantalum, niobium, and titanium are low-cost, easy-to-machine materials that have good electrical and thermal conductivity; however, they exhibit low corrosion resistance. Noble metal and metal nitride coatings are usually investigated to minimize corrosion and interfacial contact resistance. Because of its performance-to-cost ratio, Stainless Steel (SS) based materials are among the most popular materials for BPP development. This study recommends material and operating parameters to improve PEMWE systems for sustainable hydrogen production’s efficiency, durability, and economic viability.

Muti-Filler Composites Reinforced with Multiwalled Carbon Nanotubes and Chopped Carbon Fibers for the Bipolar Plate of Fuel Cells

To improve the conductivity and flexural strength of bipolar plates for proton-exchange membrane fuel cells, multi-filler-reinforced composites were prepared using graphite, multiwalled carbon nanotubes (MWCNTs), chopped carbon fibers (CCFs), and phenolic resin (PF). The effects of CCF content (0–6 wt.%) and MWCNT content (0–8 wt.%) on the flexural strength, electrical conductivity, interfacial contact resistance (ICR), density, hydrophobicity, and corrosion behavior of the composites were investigated. Results showed that the addition of a small number of CCFs (≤4 wt.%) effectively improved the flexural strength but slightly reduced the electrical conductivity and increased the ICR of the graphite/PF/CCF composites. Further addition of MWCNTs (≤6 wt.%) significantly improved the electrical conductivity and ICR of the graphite/PF/CCF/MWCNT composites, while maintaining high flexural strength. When the composites were filled with 4 wt.% CCFs and 2 wt.% MWCNTs, their electrical conductivity, flexural strength, ICR under 1.38 MPa, and contact angle were 272.8 S/cm, 43.1 MPa, 1.19 mΩ·cm2, and 101.5°, respectively. Compared to unreinforced composites, the electrical conductivity was reduced by 27.2%, the flexural strength was increased by 65.1%, and the composite possessed favorable hydrophobicity as well as corrosion behavior. This work reveals that CCFs and MWCNTs can effectively cooperate to improve composites’ electrical and flexural strength properties.

Corrosion behavior of metallic coatings on titanium bipolar plates of proton exchange membrane water electrolysis

The corrosion resistance, conductivity, and cost of the metallic bipolar plates are the main limitations for the Proton Exchange Membrane Water Electrolysis (PEMWE) commercialization. In the present study, Ta, Nb, and Ti non-precious metallic coatings were deposited by closed-field unbalanced magnetron sputtering to increase the corrosion resistance and conductivity of titanium bipolar plates in PEMWE, respectively. The coating samples suffer from corrosion in a simulated extreme anode operating environment of PEMWE (0.5 M H2SO4 + 5 ppm HF, 80 °C, O2). The surface of the Ti coating forms the micropores due to the high dissolution rate in initial formation stage of the passivation film, resulting in a higher current density (1.41 × 10−6 A cm−2). The hydrolysis reaction of Ta coating causes the adsorption of sulfide ions, thereby affecting the density of the passivation film. Despite the Ta coating exhibiting a favorable current density (4.82 × 10−7 A cm−2), ICR (463.11 mΩ cm2) is lamentably poor. The surface of Nb coating has been completely covered by Nb2O5 and NbO2 in the simulated PEMWE environment. The reoxidation process of NbO2 promotes the rate of passivation film formation and provides excellent conductivity. Therefore, Nb coating exhibits the lowest current density and interfacial contact resistance of 2.23 × 10−8 A cm−2 and 119.78 mΩ cm2, respectively, which is very low compared to the bare titanium bipolar plates.

Fractional derivative modelling for consolidation of multilayered saturated soils with interfacial thermal contact resistance subjected to time-dependent heating and loading

In this paper, the one-dimensional rheological consolidation characteristics of multilayered saturated soil foundations under time-dependent loading and heating are investigated by considering the semi-permeability and the interface thermal resistance. By introducing the fractional derivative model and the thermos-elastic theory, a thermo-mechanical coupling model is established to describe the rheological properties of saturated soils. Semi-analytical solutions for strain, temperature increment, pore water pressure and settlement were derived through the Laplace transform and its inverse. The accuracy of the solutions proposed in this paper has been verified by comparing with existing solutions. The effects of different thermal contact models of the interface on the rheological properties of saturated soils under semi-permeable boundary are discussed, and the effects of fractional derivative order, constitutive material parameters, and thermal conductivity of soil on the thermal consolidation process are investigated. The results show that: neglecting the thermal resistance effect can result in an overestimates of the impact of rheological properties on the thermal consolidation process of saturated soils under semi-permeable boundaries; As the thermal resistance coefficient increases, the influence of soil thermal conductivity on settlement decreases.

Investigation of the Performance of Hastelloy X as Potential Bipolar Plate Materials in Proton Exchange Membrane Fuel Cells.

The phase, mechanical properties, corrosion resistance, hydrophobicity, and interfacial contact resistance of Hastelloy X were investigated to evaluate its performance in proton exchange membrane fuel cells (PEMFCs). For comparison, the corresponding performance of 304 stainless steel (304SS) was also tested. Hastelloy X exhibited a single-phase face-centered cubic structure with a yield strength of 445.5 MPa and a hardness of 262.7 HV. Both Hastelloy X and 304SS exhibited poor hydrophobicity because the water contact angles were all below 80°. In a simulated PEMFC working environment (0.5 M H2SO4 + 2 ppm HF, 80 °C, H2), Hastelloy X exhibited better corrosion resistance than 304SS. At 140 N·cm-2, the interfacial contact resistance of Hastelloy X can reach as low as 7.4 mΩ·cm2. Considering its overall performance, Hastelloy X has better potential application than 304SS as bipolar plate material in PEMFCs.

Improved corrosion resistance and interfacial conductivity of a-C/(Ti:C)/Ti nano-thin film for 316L stainless steel bipolar plates

To enhance corrosion resistance and electrical conductivity of metallic bipolar plates for proton exchange membrane fuel cells (PEMFCs), the film containing amorphous carbon (a-C) outer layer, titanium carbon compound (Ti:C) transition layer and titanium (Ti) seed layer has been deposited on the surface of 316L stainless steel (316L SS) by multi-arc ion plating method. Dense and uniform a-C/(Ti:C)/Ti nano-thin film is relatively hydrophobic and approximately 300 nm thick, presenting a clear multilayer structure. The interfacial contact resistance of 316L SS is effectively reduced from 124.97 mΩ·cm2 to 3.97 mΩ·cm2 at 1.4 MPa after modification. Electrochemical corrosion tests are investigated in the simulated cathodic PEMFCs environment (0.5 M H2SO4 and 2 ppm HF at 70 ℃ bubbled with air). Potentiodynamic polarization results reveal that the corrosion potential of a-C/(Ti:C)/Ti film modified sample is 0.23 V (vs. Ag/AgCl) and the corrosion current density is only 0.14 μA·cm−2. The durability of the a-C/(Ti:C)/Ti film was assessed by conducting potentiostatic polarization tests at various applied potentials. After 4 h potential of 0.6 V and 0.8 V (vs. Ag/AgCl) holding tests, the current densities of the modified 316L SS have stabilized at 0.076 μA·cm−2 and 0.098 μA·cm−2, respectively.

Corrosion Behavior of Ta and TiN Double-Layer-Coated SUS316L for PEMFC Bipolar Plates Using Plasma-Enhanced Atomic Layer Deposition and Magnetron Sputtering

In this study, the corrosion behavior of Ta and TiN double-layered-coated SUS316L is investigated for proton-exchange membrane fuel cells (PEMFCs) bipolar plates. The surface of SUS316L is modified by depositing 4.5 μm of Ta and 200 or 400nm of TiN using magnetron sputtering and plasma-enhanced atomic layer deposition, respectively. The experimental results reveal that this coating significantly enhances the corrosion resistance and reduces the interfacial contact resistance of the bipolar plate. Under electrochemical conditions that are 500 times more acidic than those specified by the Department of Energy (DOE), the coated SUS316L achieves a corrosion current density of only 1.0µA/cm2 at 0.6 VSCE. The corrosion current density reduces up to more than two orders of magnitude, and the interfacial contact resistance with carbon paper is below 10 mΩcm2 at compression forces below 140N/cm2, thus meeting the DOE 2025 target value for both corrosion current density and interfacial contact resistance. Our findings suggest the potential of Ta and TiN double-layered-coated SUS316L as durable bipolar plate materials for PEMFCs.