Water Electrolyzers

Electrolyzers

Alkaline, PEM and AEM Electrolyzers

Pure Hydrogen generation

Porous Transport Layers for Water Electrolyzers

Porous transport layers are equivalent to gas diffusion layers of fuel cells. They facilitate the movement of the output gases, such as hydrogen and oxygen, while ensuring efficient and uniform distribution of the feed material (water) within the cell. These layers play a crucial role in enhancing overall water electrolyzer performance by optimizing reactant delivery and product expulsion, and promoting efficient electrochemical reactions.

Cathodic Porous Transport Layers 

At the cathode side, carbon-based materials are the predominantly used porous transport layer owing to the stability of carbon under reducing conditions. enerally, thin (<1mm) sheets are used for fuel cell GDLs, while thicker panels (1.5–3.0 mm) are used for electrolyzers.  While CAPLINQ can custom-make specific thicknesses, these are what our customer most often ask us for.

Graphitized Carbon Fiber Papers and Plates
Product Thickness Thickness (mm) Density (g/cm3) Basis weight (g/m2) Through-Plane Resistance (mΩcm2) Through-Plane Resistivity (mΩcm) Voltage Loss (mV)
LINQCELL GDL 1500 0.059" 1.5 0.60 858 13.32 90.6 24.3
LINQCELL GDL 1500B 0.059" 1.5 0.60 670 21 140 39
LINQCELL GDL 1850 0.072" 1.85 0.85 1562 13.18 70.5 25.5
LINQCELL GDL 2200 0.086" 2.2 0.6 1550 17 110 35
LINQCELL GDL 2900 0.011" 2.9 0.60 1734 24.57 87.7 27.6

All values are indicative and subject to tolerance

Anodic Porous Transport Layers

At the oxygen (anode) side of water elctrolyzers, the environment is much more corrosive because of usage of pure oxygen and application of potentials as high as 2 V. The highly oxidative environment at the anode corrodes the carbon-based LGDLs, thereby forming CO(Eqn. 1) and carbonate ions (Eqn. 2) in acidic and basic media, respectively. Carbon corrosion drastically reduces the the activity and stability of the anode during galvanic or electrolytic operations. For these reasons, metal-based PTLs, more commonly titanium and nickel-based GDLs, are used at the anode of and water electrolyzers. 

Titanium as Anodic PTLs

Titanium fiber papers are the preferred PTLs at the anode of water electrolyzers due to the highly corrosive environment. Titanium offers excellent corrosion resistance, making them a preferred choice to maintain long-term performance and efficiency in these electrochemical devices.

Titanium fiber papers exhibit strong corrosion resistance in PEM water electrolyzers. They form a protective passivation layer that prevents direct contact with corrosive electrolytes, stabilizes the surface, and reduces defect-related corrosive reactions, improving device performance and durability.

 LINQCELLTM Titanium Fiber Paper Properties 

Product

Porosity (%)

 Thickness (um)*

Basis Weight (g)

Actual weight (g)**

LINQCELL TFP250

 50–60

250

45.5

18.3–22.6

LINQCELL TFP250S

60–70

250

45.5

13.7–18.1

LINQCELL TFP400

50–60

400

72.8

29–36.3

LINQCELL TFP400S

60–70

400

72.8

22–29

LINQCELL TFP600

50–60

600

109.3

44–54.5

LINQCELL TFP600S

60–70

600

109.3

32.8–43.6

LINQCELL TFP800

50–60

800

145.7

58.3–72.9

LINQCELL TFP800S

60–70

800

145.7

43.7–58.2

 

Nickel as Anodic PTLs

Nickel fiber paper is also a valuable PTL in water electrolyzers and fuel cells, facilitating reactant transport and product gas removal while maintaining strong electrical conductivity. It serves as a cost-effective alternative to titanium fiber papers. Nickel fiber paper's durability and affordability make it a practical choice for PTL applications, particularly when stable electrical performance and cost efficiency are paramount.

Property

Titanium

Nickel

Electrical Conductivity

Moderate, lower than Nickel

High, excellent electrical conductor

Corrosion Resistance

Excellent, highly corrosion-resistant

Good, less corrosion-resistant than Titanium

Cost

Expensive

Affordable, cost-effective

Oxidation Under High pH

Resistant

Susceptible, can oxidize in alkaline conditions

Weight

Lightweight

Lightweight

Mechanical Strength

High, strong

Good strength

Thermal Conductivity

Moderate

High, excellent thermal conductor

Application Suitability

Most suitable for  high-pH environments, such as alkaline fuel cells

Versatile, can be used in a wide range of environments, but may perform better in moderate pH values 

It is important to consider specific application requirements, as the choice between Titanium and Nickel as a porous transport layers will depend on factors such as pH conditions, cost constraints, electrical and thermal performance, and material availability. 

 

LINQCELLTM Nickel Fiber Paper Properties 

Product

Porosity (%)

 Thickness (um)

Elongation (%)

Tensile Strength (MPa)

LINQCELL NFP250

40–90

250

≥8

5–8

LINQCELL NFP500

50–90

500

≥8

5–8

 

Stainless Steel as Versatile Anode and Cathode PTL

Discover CAPLINQ's stainless steel fiber felts—an innovative solution for fuel cells and electrolyzers, excelling in both anode and cathode applications. Engineered with highly catalytic alloy components (Ni, Co, Fe, Mo, and Mn), these felts optimize oxygen evolution reactions at the anode while showcasing exceptional durability and resistance to hydrogen embrittlement at the cathode.

CAPLINQ's stainless steel fiber felts come in three thicknesses– 250 (LINQCELL SFP 250), 600 (LINQCELL SFP 600), and 1000 (LINQCELL SFP 1000) µm, offering adaptability for various applications and providing a reliable and advanced solution to enhance the efficiency and resilience of your systems.

General Property Comparison of LINQCELLTM Cathode Porous Transport Layers

Property

Carbon Cloth or Fabric

Graphitized Carbon Paper

Stainless Steel Fiber Paper

Electrical Conductivity

■■■□ Good 

■■■■ High

■■□□ Moderate 

Corrosion Resistance

 ■■■□ Good

■■■■ High

■■□□ Moderate 

Compressibility

 ■■■□ Good

■■■■ High

■■□□ Moderate

Cost

■■■□ Cheap

■□□□ Expensive   

■■■■ Cheapest

Weight

■■■■ Lightest

■■□□ Moderate

■□□□ Heavy

Temperature Stability

■■■■ Excellent

■■■■ Excellent

■■□□ Moderate

General Property Comparison of LINQCELLTM Anode Porous Transport Layers

Property

Titanium

Nickel

Stainless Steel

Electrical Conductivity

■■■□ Good

■■■■ High

■■□□ Moderate

Corrosion Resistance

■■■■ High

■■□□ Moderate 

■■■□ Good

Compressibility

■■□□ Moderate

■■■□ Good

■■■■ High

Cost

■□□□ Expensive

■■■■ Cheapest

■■■□ Cheap

Weight

■■■■ Lightest

■■□□ Moderate

■□□□ Heavy

Temperature Stability

■■■■ Excellent

■■■□ Good

 ■■□□ Moderate

Availability

■□□□ Rare

■■■■ Abundant

■■□□ Moderate

 

Note: The rankings provided are based on general properties and characteristics of carbon, titanium, nickel, and stainless steel. Actual performance may vary based on manufacturing processes, and environmental conditions. These rankings are intended as a broad overview and should not be the sole factor in decision-making. For precise and application-specific information, it is recommended to consult relevant scientific literature, engineering specifications, and industry experts. Additionally, advancements in materials science and technology may influence the properties of these materials over time. The rankings are subject to change based on new developments and research in the field. Contact us for your cathode and anode PTL needs.