CHLOR-ALKALI

CHLOR-ALKALI

Our NiCo Electrode for Chlor-Alkali Operations

Chlor-alkali plants produce chlorine, caustic soda, and hydrogen as a byproduct. Adjacent or integrated alkaline water electrolyzers can use our bifunctional NiCo electrode for dedicated hydrogen capacity.

Polarization (RT vs 60 °C)

TESTBED
Polarization · AEM Electrolyzer Testbed30 wt% KOH · commercial Zirfon separator1.41.51.61.71.81.92.02.10.000.250.500.751.00Current density (A/cm²)Cell potential (V)1.81 V1.62 VRoom temp · 81.8%60°C · 91.3%Baseline run with commercial Zirfon. IONZERA targets a lower membrane voltage drop.

Same electrolyte family

Chlor-alkali plants already operate in concentrated KOH or NaOH brines. Our published test cell uses 30 wt% KOH, the same family of alkaline electrolyte used in chlor-alkali production.

Industrial current density

In a 5 cm2 AEM cell with the bifunctional NiCo electrode and a commercial Zirfon separator, 0.5 A/cm2 at 1.62 V at 60 deg C (91.4% efficiency). 1.0 A/cm2 at 1.79 V at 60 deg C.

Bifunctional

Same coated electrode operates as HER cathode and OER anode at 80 mV and 260 mV overpotential (100 mA/cm2, no IR correction).

1000-hour stability

21 uV/hr voltage degradation with bifunctional NiCo electrode on both sides and commercial Zirfon separator over 1000 hours at 0.5 A/cm2 and 40 deg C.

Hydrogen at chlor-alkali sites

Chlor-alkali plants are major industrial consumers of electricity and producers of hydrogen as a byproduct of chlorine and caustic-soda manufacturing. Many chlor-alkali sites have spare power infrastructure and adjacent demand for additional hydrogen, making them natural hosts for water electrolysis capacity.

Our bifunctional NiCo electrode on Ni foam (100 to 1000 cm2), electroless-deposited, operates in the same concentrated KOH electrolyte family that chlor-alkali plants already manage. The same coated electrode acts as both HER cathode and OER anode at 80 mV and 260 mV overpotential at 100 mA/cm2 (no IR correction).

1.62 V (91.4%)

0.5 A/cm2 @ 60 deg C

1.79 V

1.0 A/cm2 @ 60 deg C

Cell-level performance with commercial Zirfon

In a 5 cm2 AEM cell with the bifunctional NiCo electrode on both sides and a commercial Zirfon separator (500 um) at 30 wt% KOH and zero-gap, the cell reaches 0.5 A/cm2 at 1.81 V at room temperature (82% efficiency) and 1.62 V at 60 deg C (91.4%). At 1.0 A/cm2 the cell measures 2.05 V at RT and 1.79 V at 60 deg C.

Stability for round-the-clock operation

Chlor-alkali plants run continuously. Adjacent electrolyzer capacity must match that uptime. Our 1000-hour run at 0.5 A/cm2 and 40 deg C with bifunctional NiCo electrode on both sides and commercial Zirfon separator showed 21 uV/hr voltage drift. Before/after LSV differ by 30 mV at the operating point.

1000-hour Stability · AEM Electrolyzer Testbed0.5 A/cm² · 40°C · 30 wt% KOH · commercial Zirfon1.701.751.801.851.9002004006008001000Time (hours)Cell potential (V)DEGRADATION0 µV/hrBefore vs after 1000 hr LSVBeforeAfterΔV = 30 mV @ 0.5 A/cm²Baseline run with commercial Zirfon. Ohmic budget shrinks further with IONZERA.

Renewable-load tolerance

Chlor-alkali sites integrating renewables face load variability. Solar-derived current schedules (9 days, peaks ~570 mA/cm2) and wind-derived schedules (100 hours, 0 to 0.78 A/cm2) were both applied to the same bifunctional NiCo electrode in the AEM cell with commercial Zirfon. DeltaV after wind cycling: 20 mV at 0.5 A/cm2.

PV-derived current profile

9 DAYS
9-Day Solar-Coupled OperationAEM testbed · 40°C · 30 wt% KOH · current density from PV irradiance0.570j (A/cm²)1.951.40V (cell)1.80 V0123456789Time (days)9 days · no driftPV irradiance → current-density schedule applied to AEM stack with commercial Zirfon.

Wind-derived current profile

100 HR
100-Hour Wind-Coupled OperationAEM testbed · 40°C · 30 wt% KOH · current density from wind variation0.780j (A/cm²)1.951.40V (cell)020406080100Time (hours)Before vs after 100 hrΔV = 20 mV @ 0.5 A/cm²Wind-data → current-density schedule applied to AEM stack with commercial Zirfon.

Evaluation path for chlor-alkali sites

Bench-scale qualification at 5 cm2 (matching our published test cell) followed by pilot-scale electrodes in the 100 to 1000 cm2 range is the typical evaluation path. The commercial Zirfon separator used in our published runs is widely available, making the reproduction straightforward for any chlor-alkali team running its own bench-scale electrolyzer.

Frequently asked questions

Why use a bifunctional NiCo electrode for chlor-alkali process?

Our bifunctional NiCo electrode operates as both HER cathode and OER anode at 80 mV and 260 mV overpotential at 100 mA/cm² in 30 wt% KOH (no IR correction). For chlor-alkali process, using a single electrode SKU on both sides simplifies stack BOM and qualification.

What cell-level performance is published?

In a 5 cm² AEM cell with bifunctional NiCo electrode on both sides and a commercial Zirfon separator (500 µm) at zero-gap, the cell logs 0.5 A/cm² at 1.81 V at room temperature (82% efficiency) and 1.62 V at 60 °C (91.4%). At 1.0 A/cm²: 2.05 V at RT and 1.79 V at 60 °C.

What is the stability baseline?

Continuous 1000-hour chronopotentiometry at 0.5 A/cm² and 40 °C in 30 wt% KOH (bifunctional NiCo electrode on both sides, commercial Zirfon separator) showed voltage drift of 21 µV/hr. Before/after linear-sweep polarization curves differ by 30 mV at the operating point.

Is the electrode validated for renewable-coupled operation?

Yes. PV-irradiance-derived current schedules applied for 9 continuous days (peaks ~570 mA/cm²) and wind-variation-derived schedules for 100 hours (0 to 0.78 A/cm²) on the same cell. ΔV at 0.5 A/cm² before and after the 100-hour wind run: 20 mV.

What substrate sizes ship?

The bifunctional NiCo electrode is produced on Ni foam in the 100 to 1000 cm² size range. Bench-scale 5 cm² coupons matching the published test cell are also available so customers can reproduce numbers on their own rig before scaling up.

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