As core equipment in the electrochemical industry, electrolyzer types and structures directly impact the efficiency, energy consumption, and product purity of the electrolysis process. Electrolyzers can be categorized into various types based on the properties of the electrolyte, electrode configuration, and application scenarios, primarily distinguishing them in their operating principles, structural design, and applicable areas.
Classification by electrolyte is the most common method of differentiation. Alkaline electrolyzers use aqueous potassium hydroxide (KOH) or sodium hydroxide (NaOH) solutions as electrolytes. They are technologically mature and cost-effective, making them widely used in the chlor-alkali industry and hydrogen production. Acidic electrolyzers use sulfuric acid (H₂SO₄) as the electrolyte, but are highly corrosive, require high material standards, and have relatively limited applications. In recent years, solid oxide electrolyzers (SOECs) have emerged, using high-temperature ceramic electrolytes operating at temperatures above 800°C. These cells enable efficient hydrogen production from water vapor electrolysis, significantly improving energy conversion efficiency compared to traditional types. However, the technology is still in its early stages of commercialization.
Electrode configuration and diaphragm design also lead to significant differences. For example, traditional chlor-alkali electrolyzers often use asbestos diaphragms or ion exchange membranes (such as Nafion membranes). The latter can separate hydroxide and chlorine, improving product purity and reducing energy consumption. In industrial-scale hydrogen production, however, filter-press electrolyzers utilize a compact bipolar electrode structure to increase current density, saving space and investment costs.
Application scenarios further differentiate electrolyzer design requirements. In the energy sector, water electrolysis for hydrogen production tends to favor low-energy, long-life proton exchange membrane (PEM) electrolyzers, which offer fast response times and are suitable for fluctuating renewable energy inputs. Electrorefining in the metallurgical industry (such as copper and aluminum production) relies on large-scale, low-voltage electrolyzers, emphasizing current stability and corrosion resistance.
In summary, the differences between electrolyzers are essentially the result of a balance between technical parameters and industry needs. In the future, with the advancement of materials science and energy transition, new, efficient, and low-carbon electrolyzers will further expand their application boundaries.
