Understanding alkaline electrolysis

An alkaline electrolyser passes a direct current between two electrodes immersed in an aqueous electrolyte solution. At the cathode, water molecules accept electrons and form hydrogen gas. At the anode, hydroxide ions release electrons and form oxygen gas. A diaphragm or microporous separator between the electrodes prevents the two gas streams from mixing while allowing ions to pass.

Because the electrolyte conducts ions, the cell can operate efficiently at moderate voltages. The hydrogen evolved at the cathode is collected and delivered to the user accessory.

Pure water is a poor electrical conductor. To run electrolysis efficiently, an electrolyte is added to increase ionic conductivity. In alkaline systems this is typically potassium hydroxide (KOH); some designs use sodium hydroxide (NaOH).

KOH is a strong base. Manufacturers specify handling, PPE, refresh schedules and disposal procedures for safe operation. Operators should follow the manufacturer's instructions for the specific machine they own.

Industrially, alkaline electrolysers operate at large scale for hydrogen production in chemicals, refining and energy applications. In consumer hydrogen wellness equipment, alkaline designs are less common than PEM, but they are used — AquaCure is a well-known example.

Alkaline systems require periodic electrolyte top-up or refresh per the manufacturer's schedule. Distilled water is used for top-ups; the electrolyte itself is added or refreshed according to the manufacturer's instructions. Used electrolyte must be handled and disposed of correctly.