A compression apparatus includes at least one compression unit, a voltage applier, an anode end plate provided on an anode separator located at a first end in a direction of stacking, a cathode end plate provided on a cathode separator located at a second end in the direction of stacking, and first and second plates provided between the cathode end plate and the cathode separator located at the second end. The compression apparatus causes, by using the voltage applier to apply a voltage, protons taken out from an anode fluid that is supplied to the anode to move to the cathode via the electrolyte membrane and produces compressed hydrogen. The first plate has formed therein a first space in which to store a cathode gas containing the compressed hydrogen. The second plate is provided with a first manifold through which the cathode gas flows and a first communicating path through which to lead, to the first space, the cathode gas having flowed in from the first manifold.

A compression apparatus includes at least one compression unit, a voltage applier, an anode end plate provided on an anode separator located at a first end in a direction of stacking, a cathode end plate provided on a cathode separator located at a second end in the direction of stacking, and first and second plates provided between the cathode end plate and the cathode separator located at the second end. The compression apparatus causes, by using the voltage applier to apply a voltage, protons taken out from an anode fluid that is supplied to the anode to move to the cathode via the electrolyte membrane and produces compressed hydrogen. The first plate has formed therein a first space in which to store a cathode gas containing the compressed hydrogen. The second plate is provided with a first manifold through which the cathode gas flows and a first communicating path through which to lead, to the first space, the cathode gas having flowed in from the first manifold.

The electrode catalyst ink includes a catalyst including a layered double hydroxide, an organic polymer, and a solvent. The solvent includes a first solvent, a second solvent, and a third solvent. The third solvent has a boiling point higher than a boiling point of the first solvent and higher than a boiling point of the second solvent. The Hansen solubility parameter distance R.sub.a1 [MPa.sup.1/2] between the third solvent and the catalyst and the Hansen solubility parameter distance R.sub.a2 [MPa.sup.1/2] between the third solvent and the organic polymer satisfy a relationship of 2.08R.sub.a1−16.0≤R.sub.a2≤2.08R.sub.a1−13.5.

The electrode catalyst ink includes a catalyst including a layered double hydroxide, an organic polymer, and a solvent. The solvent includes a first solvent, a second solvent, and a third solvent. The third solvent has a boiling point higher than a boiling point of the first solvent and higher than a boiling point of the second solvent. The Hansen solubility parameter distance R.sub.a1 [MPa.sup.1/2] between the third solvent and the catalyst and the Hansen solubility parameter distance R.sub.a2 [MPa.sup.1/2] between the third solvent and the organic polymer satisfy a relationship of 2.08R.sub.a1−16.0≤R.sub.a2≤2.08R.sub.a1−13.5.

A solid oxide electrolyzer cell (SOEC) system including a stack of electrolyzer cells configured to receive water or steam in combination with hydrogen, and a steam recycle outlet configured to recycle a portion of the water or steam

An electrolysis system and an electrolysis method wherein the electrolysis system includes a pressure-electrolytic cell and a throttle in the catholyte line, by which the catholyte flow can be divided into a gas and liquid phase. In this way, (by-)products of the electrolysis can be recycled, while the electrolytic cell can be operated effectively at a high pressure.

An electrolysis system and an electrolysis method wherein the electrolysis system includes a pressure-electrolytic cell and a throttle in the catholyte line, by which the catholyte flow can be divided into a gas and liquid phase. In this way, (by-)products of the electrolysis can be recycled, while the electrolytic cell can be operated effectively at a high pressure.

A water electrolyzer comprises a membrane, a cathode and an anode. The membrane comprises a first membrane layer comprising a first ion-conductive polymer, a second membrane layer comprising a second ion-conductive polymer, and a platinized nanostructured layer disposed between the first layer and the second layer. The platinized nanostructured layer comprises close-packed whiskers having at least one of platinum or platinum oxide disposed thereon. The cathode is disposed on the membrane and comprises a first catalyst consisting essentially of both metallic Pt and Pt oxide. The anode is disposed on the opposite surface of the membrane and comprises a second catalyst comprising at least 95 percent by weight of collectively metallic Ir and Ir oxide, calculated as elemental Ir, based on the total weight of the second catalyst, wherein at least one of metallic Ir or Ir oxide is present. Membranes and methods of making them are also disclosed.

A water electrolyzer comprises a membrane, a cathode and an anode. The membrane comprises a first membrane layer comprising a first ion-conductive polymer, a second membrane layer comprising a second ion-conductive polymer, and a platinized nanostructured layer disposed between the first layer and the second layer. The platinized nanostructured layer comprises close-packed whiskers having at least one of platinum or platinum oxide disposed thereon. The cathode is disposed on the membrane and comprises a first catalyst consisting essentially of both metallic Pt and Pt oxide. The anode is disposed on the opposite surface of the membrane and comprises a second catalyst comprising at least 95 percent by weight of collectively metallic Ir and Ir oxide, calculated as elemental Ir, based on the total weight of the second catalyst, wherein at least one of metallic Ir or Ir oxide is present. Membranes and methods of making them are also disclosed.

A cathode is provided for electrolysis of water wherein the cathode material comprises a multi-principal element, transition metal dichalcogenide material that has four or more chemical elements and that is a single phase, solid solution. The pristine cathode material does not contain platinum as a principal (major) component. However, a cathode comprising a transition metal dichalcogenide having platinum (Pt) nanosized islands or precipitates disposed thereon is also provided.