Electrochemical hydrogen compressor

An electrochemical hydrogen compressor is a hydrogen compressor where hydrogen is supplied to the anode, and compressed hydrogen is collected at the cathode with an exergy efficiency up to and even beyond 80% for pressures up to 10,000 psi or 700 bars. A multi-stage electrochemical hydrogen compressor incorporates membrane-electrode-assemblies (MEAs) separated by proton exchange membranes (PEMs) in series to reach higher pressures, when a current is passed through the MEA protons and electrons are generated at the anode.

Proton-exchange membrane fuel cell

proton exchange membrane fuel cellPEMPEMFC
Proton-exchange membrane fuel cells, also known as polymer electrolyte membrane (PEM) fuel cells (PEMFC), are a type of fuel cell being developed mainly for transport applications, as well as for stationary fuel-cell applications and portable fuel-cell applications. Their distinguishing features include lower temperature/pressure ranges (50 to 100 °C) and a special proton-conducting polymer electrolyte membrane. PEMFCs generate electricity and operate on the opposite principle to PEM electrolysis, which consumes electricity. They are a leading candidate to replace the aging alkaline fuel-cell technology, which was used in the Space Shuttle.

Electroosmotic pump

One application of this is removing liquid flooding water from channels and gas diffusion layers and direct hydration of the proton exchange membrane in the membrane electrode assembly (MEA) of the proton exchange membrane fuel cells. Electroosmotic pumps are fabricated from silica nanospheres or hydrophilic porous glass, the pumping mechanism is generated by an external electric field applied on an electric double layer (EDL), generates high pressures (e.g., more than 340 atm (34 MPa) at 12 kV applied potentials) and high flow rates (e.g., 40 ml/min at 100 V in a pumping structure less than 1 cm³ in volume).

Polymer electrolyte membrane electrolysis

PEM electrolysiselectrolyzersPEM
Proton exchange membrane (PEM) electrolysis is the electrolysis of water in a cell equipped with a solid polymer electrolyte (SPE) that is responsible for the conduction of protons, separation of product gases, and electrical insulation of the electrodes. The PEM electrolyzer was introduced to overcome the issues of partial load, low current density, and low pressure operation currently plaguing the alkaline electrolyzer. However, a recent scientific comparison showed that state-of-the-art alkaline water electrolysis shows competitive or even better efficiencies than PEM water electrolysis.


Nafion was found effective as a membrane for proton exchange membrane (PEM) fuel cells by permitting hydrogen ion transport while preventing electron conduction. Solid Polymer Electrolytes, which are made by connecting or depositing electrodes (usually noble metal) to both sides of the membrane, conduct the electrons through an energy requiring process and rejoin the hydrogen ions to react with oxygen and produce water. Fuel cells are expected to find strong use in the transportation industry. Nafion, as a superacid, has potential as a catalyst for organic synthesis.

Glossary of fuel cell terms

bipolar platefuel-cell stackFuel processing
A unitized regenerative fuel cell (URFC) is a fuel cell based on the proton exchange membrane which can do the electrolysis of water in regenerative mode and function in the other mode as a fuel cell recombining oxygen and hydrogen gas to produce electricity. It is usually represented by the symbol Q. It measures a rate of energy use or production. This can apply to materials that store hydrogen or for the entire storage system (e.g., material or compressed/liquid hydrogen as well as the tank and other equipment required to contain the hydrogen such as insulation, valves, regulators, etc.). For example, 6 wt.% on a system-basis means that 6% of the entire system by weight is hydrogen.

Electrolysis of water

water electrolysiselectrolysiselectrolyzer
There are two main technologies available on the market, alkaline and proton exchange membrane (PEM) electrolyzers. Alkaline electrolyzers are cheaper in terms of investment (they generally use nickel catalysts), but less efficient; PEM electrolyzers, conversely, are more expensive (they generally use expensive platinum-group metal catalysts) but are more efficient and can operate at higher current densities, and can, therefore, be possibly cheaper if the hydrogen production is large enough. Conventional alkaline electrolysis has an efficiency of about 70%.


HH 2 hydrogen gas
When determining the electrical efficiency of PEM (proton exchange membrane) electrolysis, the higher heat value (HHV) is used. This is because the catalyst layer interacts with water as steam. As the process operates at 80 °C for PEM electrolysers the waste heat can be redirected through the system to create the steam, resulting in a higher overall electrical efficiency. The lower heat value (LHV) must be used for alkaline electrolysers as the process within these electrolysers requires water in liquid form and uses alkalinity to facilitate the breaking of the bond holding the hydrogen and oxygen atoms together.


fluoropolymersfluorocarbon polymersfluorinated polymer
A fluoropolymer is a fluorocarbon-based polymer with multiple carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases. The best known fluoropolymer is polytetrafluoroethylene (Teflon).

Carbon monoxide

COcarbon monoxide (CO)carbon monoxide poisoning
Carbon monoxide (CO) is a colorless, odorless, and tasteless flammable gas that is slightly less dense than air. It is toxic to animals that use hemoglobin as an oxygen carrier (both Invertebrate and vertebrate) when encountered in concentrations above about 35 ppm, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal biological functions. In the atmosphere, it is spatially variable and short lived, having a role in the formation of ground-level ozone. Carbon monoxide consists of one carbon atom and one oxygen atom, connected by a triple bond that consists of two covalent bonds as well as one dative covalent bond.

Johnson thermoelectric energy converter

Johnson Thermo-Electrochemical Converter SystemSolid-state engine
Each stage consists of a working fluid chamber that a copper lined membrane electrode assembly (MEA) bisects. A MEA is a proprietary ceramic proton exchange membrane (PEM) that is sandwiched between two electrodes. In the high-temperature power stage, expanding high pressure hydrogen from the compression stage converts the heat energy into electrical energy via the MEA. As the high-temperature, high pressure hydrogen is forced through the PEM it is ionized, producing protons and electrons. The protons pass through the membrane while the electrodes expel the electrons through a load.

Hydrogen production

production of hydrogenproduce hydrogenproduction
There are two main technologies available on the market, alkaline and proton exchange membrane (PEM) electrolysers. Traditionally, alkaline electrolysers are cheaper in terms of investment (they generally use nickel catalysts), but less efficient; PEM electrolysers, conversely, are more expensive (they generally use expensive platinum-group metal catalysts) but are more efficient and can operate at higher current densities, and can therefore be possibly cheaper if the hydrogen production is large enough. Conventional alkaline electrolysis has an efficiency of about 70%, however thyssenkrupp have recently developed an advanced alkaline water electrolyser with an efficiency of 82%.

Ion-exchange membranes

ion exchange membranesion exchange membranecation exchange membrane
Important examples of ion-exchange membranes include the proton-exchange membranes, that transport [[hydrogen|]] cations, and the anion exchange membranes used in certain alkaline fuel cells to transport [[Hydroxyl|]] anions. An ion-exchange membrane is generally made of organic or inorganic polymer with charged (ionic) side groups, such as ion-exchange resins. Anion-exchange membranes contain fixed cationic groups with predominantly mobile anions; because anions are the majority species, most of the conductivity is due to anion transport. The reverse holds for cation-exchange membranes.


gas compressorcompressorscompression
Rotary lobe compressors are often used to provide air in pneumatic conveying lines for powder or solids. Pressure reached can range from 0.5 to 2 bar g. Axial compressor. Cabin pressurization. Centrifugal fan. Compressed air. Compressed air dryer. Electrochemical hydrogen compressor. Energy-saving rotary Blade compressor Patent numbers: EP0933500. Fire piston. Foil bearing. Gas compression heat pump. Guided rotor compressor. Hydrogen compressor. Linear compressor. Liquid ring compressor. Hydride compressor. Natterer compressor. Pneumatic cylinder. Pneumatic tube. Reciprocating compressor (piston compressor). Roots blower (a lobe-type compressor). Slip factor. Trompe.

Fuel cell

fuel cellshydrogen fuel cellfuel-cell
The membrane electrode assembly (MEA) is referred as the heart of the PEMFC and is usually made of a proton exchange membrane sandwiched between two catalyst-coated carbon papers. Platinum and/or similar type of noble metals are usually used as the catalyst for PEMFC. The electrolyte could be a polymer membrane. Phosphoric acid fuel cells (PAFC) were first designed and introduced in 1961 by G. V. Elmore and H. A. Tanner. In these cells phosphoric acid is used as a non-conductive electrolyte to pass positive hydrogen ions from the anode to the cathode. These cells commonly work in temperatures of 150 to 200 degrees Celsius.

Ionic liquid piston compressor

Electrochemical hydrogen compressor. Guided rotor compressor. Hydride compressor. Linear compressor. Timeline of hydrogen technologies.

Compressed hydrogen

CGH2hydrogen gascompressed-hydrogen
Gas compressor. Gasoline gallon equivalent. Hydrogen compressor. Liquid hydrogen. Liquefaction of gases. Metallic hydrogen. Slush hydrogen. Standard cubic foot. Timeline of hydrogen technologies.

Proton conductor

conduct protonspositive charge flow
A proton conductor is an electrolyte, typically a solid electrolyte, in which H + are the primary charge carriers.

Hydride compressor

An example of current use are hydrogen sorption cryocoolers and portable metal hydride compressors. Electrochemical hydrogen compressor. Guided rotor compressor. Hydrogen storage. Ionic liquid piston compressor. Linear compressor. Sodium aluminium hydride. Timeline of hydrogen technologies.


Membrane electrode assembly. Electrodes for Taser electroshock weapon. Working electrode. Reference electrode. Gas diffusion electrode. Cellulose electrode. Battery. Redox (Reduction-Oxidation Reaction). Cathodic protection. Galvanic cell. Anion vs. Cation. Electron versus hole. Electrolyte. Electron microscope. Noryl. Tafel equation. Hot cathode. Cold cathode. Electrolysis. Reversible charge injection limit.

Ballard Power Systems

BallardBallard PowerBallard fuel cell membrane
Ballard Power Systems Inc. is a developer and manufacturer of proton exchange membrane (PEM) fuel cell products for markets such as heavy-duty motive (consisting of bus and tram applications), portable power, material handling as well as engineering services. Ballard has designed and shipped over 400 MW of fuel cell products to date. Ballard was founded in 1979 under the name Ballard Research Inc. to conduct research and development on high-energy lithium batteries. Since committing to the development of PEM fuel cell technology in 1989, Ballard has delivered PEM fuel cell products worldwide to a number of leading product manufacturers.

Guided-rotor compressor

Guided rotor compressor
The guided-rotor compressor (GRC) is a positive-displacement rotary gas compressor. The compression volume is defined by the trochoidally rotating rotor mounted on an eccentric drive shaft with a typical 80 to 85% adiabatic efficiency. The development of the GRC started in 1990 to minimize the use of compressor valve plates and springs by using simple inlet/discharge ports. The guided-rotor compressor is under research as a hydrogen compressor for hydrogen stations and hydrogen pipeline transport. Liquid ring. Rotary screw compressor. Rotary vane pump.

Synthetic membrane

membranemembranesartificial membrane
The most important functional materials in this category include proton exchange membranes and alkaline anion exchange membranes, that are at the heart of many technologies in water treatment, energy storage, energy generation. Applications within water treatment include reverse osmosis, electrodialysis, and reversed electrodialysis. Applications within energy storage include rechargeable metal-air electrochemical cells and various types of flow battery. Applications within energy generation include proton exchange membrane fuel cells (PEMFCs), alkaline anion exchange membrane fuel cells (AEMFCs), and both the osmotic- and electrodialysis-based osmotic power or blue energy generation.