There are provided system for preparing lithium hydroxide from an aqueous composition comprising a lithium compound and use of the system thereof to prepare lithium hydroxide, the system comprising an electrochemical cell, a pH probe and at least one inlet for receiving acid or base for maintaining pH. For example, the lithium compound can be lithium sulphate and the aqueous composition can be at least substantially maintained at a pH having a value of about 2 to about 4.

There are provided system for preparing lithium hydroxide from an aqueous composition comprising a lithium compound and use of the system thereof to prepare lithium hydroxide, the system comprising an electrochemical cell, a pH probe and at least one inlet for receiving acid or base for maintaining pH. For example, the lithium compound can be lithium sulphate and the aqueous composition can be at least substantially maintained at a pH having a value of about 2 to about 4.

A method for manufacturing a sulfuric acid solution includes supplying a chloride ion-containing sulfuric acid solution as an initial electrolyte in an electrolyzer inside of which is divided into an anode chamber and a cathode chamber by a diaphragm; and subsequently taking out a metal dissolved electrolyte in which a metal constituting the anode is dissolved from the anode chamber while supplying a current to an anode and a cathode disposed in the electrolyzer.

A method for manufacturing a sulfuric acid solution includes supplying a chloride ion-containing sulfuric acid solution as an initial electrolyte in an electrolyzer inside of which is divided into an anode chamber and a cathode chamber by a diaphragm; and subsequently taking out a metal dissolved electrolyte in which a metal constituting the anode is dissolved from the anode chamber while supplying a current to an anode and a cathode disposed in the electrolyzer.

A method of forming a gas diffusion layer includes causing, at least in part, a stack of layers to be arranged between compressing surfaces of a press, the stack of layers including a plurality of gas diffusion layers. The method also includes causing, at least in part, the press to apply one or more compression cycles to the stack of layers to reduce a combined, uncompressed thickness of the plurality of gas diffusion layers between about 2% and about 30%.

A method of forming a gas diffusion layer includes causing, at least in part, a stack of layers to be arranged between compressing surfaces of a press, the stack of layers including a plurality of gas diffusion layers. The method also includes causing, at least in part, the press to apply one or more compression cycles to the stack of layers to reduce a combined, uncompressed thickness of the plurality of gas diffusion layers between about 2% and about 30%.

A separator for alkaline electrolysis comprising a support (10) and a porous layer (20) provided on the support, characterized in that the support is capable of being substantially removed from the separator. The support is preferably removed by the electrolyte of an alkaline electrolyser.

A separator for alkaline electrolysis comprising a support (10) and a porous layer (20) provided on the support, characterized in that the support is capable of being substantially removed from the separator. The support is preferably removed by the electrolyte of an alkaline electrolyser.

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, a first seal material that surrounds an outer periphery of the cathode, and a second seal material that surrounds an outer periphery of a first space in which to store compressed hydrogen, the first space being 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. An area of a region surrounded by the second seal material is larger than an area of a region surrounded by the first seal material.

A water electrolysis cell includes an anode disposed on one side across a solid polymer electrolyte membrane and a cathode disposed on another side. The anode is configured of an anode catalyst layer, an anode gas diffusion layer, and an anode separator, laminated in that order from a side of the solid polymer electrolyte membrane, a channel is provided in the anode separator, and the channel extends in a wave shape.