FS-990-PK Cation Exchange Membrane

The FS-990-PK is a 90-105 µm, PK-reinforced fluoropolymer cation exchange membrane supplied dry in H+ form, appearing as a trans-illuminant yellow-to-beige layer on a fully transparent PET backing that separates away before mounting. Its conductivity is validated not only in redox flow and electrolysis test cells but by EIS in both PEM water electrolysis and PEM fuel cell hardware, and for electrolysis work in particular it can activate in-situ without any acid pretreatment, or be conditioned for 6+ hours in 10 wt% H2SO4 at 70-100 °C for immediate peak performance. The polyketone reinforcement mesh pushes Young's modulus above 700 MPa and tensile strength above 40 MPa, while a 1.11-1.22 meq/g ion exchange capacity keeps conductivity above 60 mS/cm in 0.5 M H2SO4.

• PEM Fuel Cell & Electrolysis Validated: Conductivity confirmed via EIS in both PEM water electrolysis and PEM fuel cell hardware, not just flow battery cells.
• Flexible Activation: Activates in-situ in the cell (especially for electrolysis), or pretreat 6+ hours in 10 wt% H2SO4 at 70-100 °C for immediate peak performance.
• High Capacity, Low Mass: 1.11-1.22 meq/g ion exchange capacity drives conductivity above 60 mS/cm in 0.5 M H2SO4 at just 14-18 mg/cm² areal weight.
• Polyketone-Reinforced: PK mesh backbone raises Young's modulus above 700 MPa for stack assemblies under sustained compression.
• Stack-Ready Mechanicals: >40 MPa tensile strength simplifies handling and cutting during multi-cell stack assembly.
• Multiple Cut Formats: Standard sheets or pre-cut for Redox Flow's X-Stack, S-Stack, and 3-compartment hardware.