Advanced Ionics, an American clean tech company founded in 2017, develops a breakthrough electrolyzer technology that uses industrial waste heat to produce green hydrogen without a green premium. By reducing the amount of electricity needed for electrolysis, the company aims to lower the price of green hydrogen. Advanced Ionics' technology is ideally suited for industrial clients seeking to upgrade, expand, or replace their hydrogen production facilities.Â
Challenges: hydrogen fuel
Electrolysis is the process by which an electrolyzer separates water into hydrogen and oxygen using electricity.
An electrolyzer consists of a cathode (negative charge), an anode (positive charge), and a membrane in its most fundamental form. Other components of the system include pumps, vents, storage tanks, a power supply, and a separator.
The electrolyzer system generates hydrogen and oxygen gas through electrolysis. The hydrogen gas can either be compressed or liquefied for storage. Hydrogen is an energy carrier that can be used to power any hydrogen fuel cell electric application without carbon emission, including trains, buses, trucks, ships, aircraft, and data centers.
There are two types of electrolyzers: hot and cold.
Cold Electrolyzers
Cold electrolyzers, such as alkaline, proton exchange membrane (PEM), and others, use liquid water. (Their operating temperature is typically limited to 100 ºC.).
Alkaline electrolyzers are the most prevalent electrolysis technology, as well as the least expensive and least effective.
In alkaline electrolyzers, hydrogen is typically produced in a cell composed of electrodes, a microporous separator, and an aqueous alkaline electrolyte containing approximately 30% potassium hydroxide (KOH) or sodium hydroxide (NaOH). Ni with a catalytic coating such as Pt is the most common cathode material, and Ni or Cu coated with metal oxides such as Mn, W, or Ru is the most common anode material.
Typically, in alkaline electrolyzers, the cells are stacked in series to produce more hydrogen and oxygen as the number of cells increases. When a current is applied to the cell stack, the hydroxide ions move from the cathode to the anode of each cell through the electrolyte. The electrolyzer produces hydrogen gas bubbles at the cathode and oxygen gas bubbles at the anode.
PEM electrolysers typically employ Pt black, Ir, Ru, and Rh as electrode catalysts, a solid polymer electrolyte, and a Nafion membrane that not only separates the electrodes but also functions as a gas separator. Water splits into hydrogen and oxygen when a current is applied to the cell stack, and protons pass through the membrane to form hydrogen on the cathode side.
PEM electrolysers have a number of advantages over alkaline electrolysers, including higher product gas purity, lower power consumption, fewer adverse environmental effects, and smaller overall system dimensions. However, the water purity requirements for PEM electrolyzers are significantly higher. PEM electrolysers are currently being developed.
Cold electrolyzers require substantial amounts of electricity to coax a liquid into electrolysis, at least 40 kWh to produce one kilogram of hydrogen, and frequently more than 50 kWh. Worse yet, many of these systems require costly platinum and iridium metals as well as exotic, fragile polymers.
Hot Electrolyzers
Hot electrolyzers, such as solid oxide electrolysis cells (SOEC), operate with superheated steam at 800 ºC, which increases reaction kinetics and decreases electrical energy needs.
SOECs use a solid ceramic material as the electrolyte that selectively transfers negatively charged oxygen ions to the anode. At the cathode, unlike PEM and alkaline electrolysers, water is dissociated into hydrogen and oxygen ions.
SOECs possess the highest electrical efficiency. However, additional energy is required to heat industrial steam to the required temperature. In addition, hot electrolyzers utilize delicate and costly ceramics, which increase capital costs and decrease reliability. SOEC units are the most primitive.
Most electrolyzer technologies rely on the fundamental structure of an anode, a cathode, and an electrolyte between them. Typically, the electrolyte is a solid or liquid that is highly insulating electrically but facilitates ion transfer between the anode and cathode. Due to its high theoretical energy conversion efficiencies and modularity, this design is relatively adaptable to diverse systems.
However, this design has numerous limitations that prevent these devices from operating to their fullest capacity.
The first restriction pertains to the interface between the electronic conducting material, the ionic conducting material, the reactants, and the products. This is demonstrated, for instance, in the three phase boundary region of fuel cells, where electron, ion, and reactant/product meet. This region frequently occurs at the catalyst, which is required for the reaction to proceed. Because of this, only about one-third of the catalyst can be utilized in a modern proton-exchange membrane fuel cell, as the remaining two-thirds lack access to at least one of the three necessary components.
The second limitation concerns the transport of reactants and products in mass quantities. Reactants and products must compete for the same volume of space, one entering the apparatus and the other leaving it.
Advanced Ionics Technology
The magic of Advanced Ionics lies in the middle. Significantly, its Symbiotic Electrolyzers technology utilizes process or waste heat above 150 ºC, whereas the majority of industrial processes operate between 200 and 600 ºC.
By utilizing excess heat that is already present in industrial settings, the electrolyzers reduce their electricity consumption. Symbiotic Electrolyzers require 35 kWh of electricity to produce one kilogram of hydrogen, which is 30 percent less than high-end alkaline or PEM systems, which require approximately 50 kWh per kilogram of hydrogen. In addition, the technology of Advanced Ionics uses abundant and widely accessible materials to keep capital costs low – no costly platinum-group metals, no iridium, and no fluoropolymer membranes.
The current levelized cost of producing green hydrogen through electrolysis is approximately $4 to $5 per kilogram. Using Symbiotic steam electrolysis, Advanced Ionics' electrolysis can provide clean hydrogen without the green premium for less than $1/kg in numerous industrial settings. Amazing!
How did Advanced Ionics achieve this feat?
The most innovative aspect of Advanced Ionics is its electrode architecture.