Hysata, an Australian cleantech startup founded in 2021, develops a unique capillary-fed electrolysis cell to produce green hydrogen. The cell produces green hydrogen from water with a 98% energy efficiency, outperforming the existing electrolyzer technologies and achieving the 2050 goal of the International Renewable Energy Agency’s (IRENA). Hysata enables hydrogen production that costs US$1.50/kg hydrogen.
Challenges: hydrogen fuel
Green hydrogen is a crucial element of the future net-zero world. Using electricity from renewable sources, such as nuclear, solar, and wind, to split water produces green hydrogen. Green hydrogen can decarbonize hard-to-abate industries, such as steel manufacture, long-distance transportation, shipping, and aviation. It can also be used to store renewable electricity seasonally and as a chemical feedstock.
However, green hydrogen is not cost-competitive with fossil fuels at this time. This is as a result of the high capital expenditure (CAPEX) and high operational expenditure (OPEX) of the present-day water electrolysis plants. The OPEX is by far the largest cost component, and it is dominated by the overall energy efficiency of the water electrolyzer and the cost of the input renewable electricity used to power it.
Modern commercial water electrolyzers at sub-MW scale typically require ~53 kWh of electricity to produce 1 kg of hydrogen, which contains 39.4 kWh of energy (net energy present in hydrogen, or its higher heating value). The 83% energy-efficient electrolysis cell consumes ~47.5 kWh of this total, while the engineering system consumes the remaining ~5.5 kWh. The International Renewable Energy Agency (IRENA) has set a 2050 target of below42 kWh/kgH₂ for cell energy consumption.
Thus, any improvement in net energy efficiency results in a proportional decrease in the levelized cost of hydrogen (LCOH). The figure below shows the impact of increasing the electrolysis cell energy efficiency from 75% to 95% on the levelized cost of hydrogen.
Hysata developed a low-cost alkaline capillary-fed electrolysis cell with high energy efficiency. The hydrogen- and oxygen-evolving electrodes come into contact with water via capillary-induced transport along a porous inter-electrode separator, resulting in bubble-free operation at the electrodes. The electrolysis cell has a 98% energy efficiency for water electrolysis, which is superior to commercial electrolysis cells. It consumes significantly less energy (40.4 kWh/kg hydrogen) than commercial electrolysis cells (47.5 kWh/kg hydrogen). High energy efficiency and the promise of a simplified balance-of-plant bring cost-competitive renewable hydrogen closer to reality.
Hysata electrolysis cell
The figure below depicts the structure of the alkaline capillary-fed electrolysis cell. The cell consists primarily of bipolar plates, conducting gas diffusion layers, anode, cathode, a porous separator, and an aqueous 27%wt KOH electrolyte.
The polyethersulfone separator is porous and hydrophilic. The bottom end of the separator is dipped into a reservoir, resulting in capillary-induced, upward, in-plane, movement of electrolyte. The thin and porous polyethersulfone separator has a low ionic resistance, which contributes to a high energy efficiency of the capillary-fed cell. The polyethersulfone separator can support water electrolysis at 1 A cm⁻² and ≥80 °C for a height of up to 18 cm. This height restriction is created by gravity.
Both porous gas diffusion electrodes are held against opposite sides of the separator, above the electrolyte level. The anode consists of a fine Ni mesh electrocoated with a NiFeOOH electrocatalyst for oxygen evolution. Ni mesh is spot-welded to its bipolar plate. The cathode is a Pt/C electrocatalyst for hydrogen evolution made by depositing Pt (a loading of 0.5 mg cm⁻²) on a conducting carbon paper gas diffusion layer. As the carbon paper could not be welded, the cathode was pressed tightly against its bipolar plate.
The bipolar plate electrically connects to their corresponding electrode via a conducting gas diffusion layer. Bipolar plates are normally employed to carry current into and out of electrolysis cells. It consists of a sheet of Ni with many small holes to allow evolved gasses to exit the electrode.
Hysata green hydrogen
The figure below depicts the working mechanism of the capillary-fed electrolysis cell to produce hydrogen.
The application of sufficient voltage between the electrodes results in the electrolysis of water. Both gasses are produced directly in gas collection chambers, rather than bubbling through the liquid electrolyte. The aqueous electrolyte continuously moves up to the electrodes by a spontaneous capillary action in the porous, hydrophilic, inter-electrode separator. The water flow to an electrode does not counteract gas flow away from the electrode, thereby avoiding the counter multiphase flows inherent in conventional water electrolyzers and their associated mass transport limitations.
The electrodes draw in liquid laterally from the separator and are covered with a thin layer of the electrolyte. Because the generated hydrogen and oxygen gasses readily migrate through the thin layer of liquid electrolyte covering their respective electrodes, the capillary-fed cell concept provides for bubble-free electrolysis in which water is converted directly to the bulk gasses without forming gas bubbles.
The alkaline capillary-fed electrolysis cell requires only 1.506 V at 0.5 A cm⁻², which represents a cell energy efficiency of 98% with consumption of only 40.4 kWh kg⁻¹ H₂, realizing a 15% improvement in cell energy efficiency and the IRENA 2050 target of <42 kWh kg⁻¹.
The capillary-fed electrolysis cell also shows sustained stable performance over extended periods from one working day to 30 days continuously at 80 ºC and room temperature, respectively, with periodic replenishment of the consumed water to the reservoir.
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Hysata Technology Applications
The Hysata electrolyzer is expected to play a crucial role in decarbonizing hard-to-abate sectors such as steel, chemicals, high-grade heat, and heavy transport. Green hydrogen, produced by electrolyzers, is expected to contribute 20% of the total abatement required by 2050 for net zero and supply 10–15% of energy in a net zero global economy.
Hysata is working on the development of a 200 kW electrolyzer system and plans to develop and test a 5 MW unit at its new electrolyzer manufacturing facility in Port Kembla, New South Wales.
Hysata’s electrolyzer technology offers several advantages over existing systems. It increases the amount of hydrogen produced per MW of electrolyzer capacity, producing 580 kg of green hydrogen per day per MW, compared to around 470 kg for incumbent electrolyzer systems. It also requires significantly less water, around 13 L/kg of hydrogen produced, compared to around 60 L/kg for incumbent electrolysers.
Hysata has raised a total of A$42.5M in funding over a Series A round raised on Aug 1, 2022.
Hysata is funded by 6 investors:
Paul Barrett is Founder.
Paul Barrett is CEO.
Hysata Board Member and Advisor
Alan Finkel is an advisor.
Blair Pritchard is a board member.