SOLAR-COUPLED H2
SOLAR-COUPLED H2Our NiCo Electrode for Solar-to-Hydrogen
Solar PV generates a daily cycle of current. Our bifunctional NiCo electrode in an AEM cell with a commercial Zirfon separator was tested under a PV-irradiance-derived current schedule for 9 continuous days. No major changes were observed.
Polarization (RT vs 60 °C)
TESTBED9-day PV-cycle test
PV-derived current schedule peaking ~570 mA/cm2 applied to bifunctional NiCo + commercial Zirfon in an AEM cell for 9 continuous days. No major changes observed.
Industrial current density at the operating point
During peak solar windows the cell delivers near the published cell-level baseline: 0.5 A/cm2 at 1.62 V at 60 deg C (91.4% efficiency) with bifunctional NiCo and commercial Zirfon separator.
Bifunctional
80 mV / 260 mV at 100 mA/cm2 (no IR correction).
Stable baseline
1000-hour steady-load reference at 0.5 A/cm2 / 40 deg C: 21 uV/hr drift.
Solar PV produces a non-flat current schedule
Solar PV connected directly to an electrolyzer (without battery buffering) produces current that ramps up from zero at sunrise, peaks around solar noon, and ramps down to zero at sunset. Electrolyzer components see the same daily envelope.
Our bifunctional NiCo electrode on Ni foam (100 to 1000 cm2), electroless-deposited, has been tested in an AEM cell with a commercial Zirfon separator (500 um) under a PV-derived current schedule. The same coated 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).
Continuous duration
Peak current density
9 continuous days of solar-derived cycling
Solar-irradiance data sampled sunrise to sunset was converted into a current-density schedule peaking near 570 mA/cm2 and applied to the AEM cell with our bifunctional NiCo electrode on both sides and a commercial Zirfon separator. The cell was operated continuously for 9 days at 40 deg C in 30 wt% KOH. Cell voltage tracked the input profile and no major changes were observed after 9 cycles.
Peak vs trough operating points
During the solar-peak windows the bifunctional NiCo electrode and commercial Zirfon separator operate near the cell's published high-current baseline. During morning ramp and evening ramp the cell is at low current density. The 9-day run exercised the full daily envelope; the electrode held its operating envelope across all 9 cycles.
Cross-check with steady-load and wind data
Alongside the 9-day solar run, the same bifunctional NiCo electrode and commercial Zirfon separator hold the 1000-hour steady-load baseline (21 uV/hr drift at 0.5 A/cm2 / 40 deg C) and the 100-hour wind-derived dynamic load (ΔV = 20 mV at 0.5 A/cm2 before vs after).
PV-derived current profile
9 DAYSWind-derived current profile
100 HRFrequently asked questions
Why use a bifunctional NiCo electrode for solar-to-hydrogen?
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 solar-to-hydrogen, 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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