Introduction

As the world shifts toward renewable energy, green hydrogen—produced using electrolysis powered by clean electricity—has emerged as a key player in decarbonizing industries like transportation, steelmaking, and chemicals. Among the different electrolyzer technologies, alkaline electrolyzers (ALK) currently dominate the market. But why?

In this blog, we’ll explore the advantages of alkaline electrolyzers, their role in green hydrogen production, and why they remain the preferred choice for large-scale projects.

 

What Are Alkaline Electrolyzers?

Alkaline electrolyzers have been around for decades and are one of the most mature technologies for hydrogen production. They use an alkaline solution (typically potassium hydroxide, KOH) as an electrolyte and nickel-based electrodes to split water (H₂O) into hydrogen (H₂) and oxygen (O₂) through an electrochemical reaction.

Key Reaction:

At the cathode: 2H₂O + 2e⁻ → H₂ + 2OH⁻
At the anode: 2OH⁻ → ½O₂ + H₂O + 2e⁻

 

Why Alkaline Electrolyzers Dominate the Market

1. Proven Technology & Reliability

Alkaline electrolyzers have been used for industrial hydrogen production since the early 20th century. Their long track record makes them a low-risk choice for large-scale projects compared to newer technologies like PEM (Proton Exchange Membrane) or SOEC (Solid Oxide Electrolyzers).

2. Lower Capital Costs

One of the biggest advantages of ALK systems is their cost-effectiveness. They use non-precious metals (e.g., nickel instead of platinum or iridium), making them significantly cheaper than PEM electrolyzers, which rely on expensive catalysts.

3. Scalability for Industrial Use

Alkaline electrolyzers are ideal for large-scale hydrogen production, such as ammonia plants or refineries.

4. Longer Lifespan & Durability

With fewer degradation issues than PEM systems, ALKs often have lifespans about 20 years, reducing long-term operational costs. Their robust construction makes them suitable for harsh industrial environments.

5. Compatibility with Renewable Energy

While ALKs traditionally required stable power inputs, advancements in dynamic operation have improved their ability to work with intermittent renewable sources like wind and solar.

 

Challenges & Future Improvements

Despite their advantages, alkaline electrolyzers face some limitations:

Lower Efficiency at Partial Loads – They perform best at steady, high-capacity operation.

Slower Response Times – Less flexible than PEM electrolyzers for rapid start-stop cycles.

Liquid Electrolyte Maintenance – Requires periodic refilling and corrosion management.

 

However, innovations such as:
Advanced electrode materials (improving efficiency)
Zero-gap configurations (reducing energy losses)
Hybrid systems (ALK + PEM)
are helping ALKs stay competitive.

 

Conclusion: Alkaline Electrolyzers Lead the Green Hydrogen Race

While newer electrolyzer technologies are gaining attention, alkaline electrolyzers remain the market leader due to their cost efficiency, scalability, and proven reliability. As green hydrogen demand grows, ALKs will continue playing a crucial role in the energy transition—especially for large industrial applications.

For now, they are the go-to solution for cost-effective, large-scale green hydrogen production.

Given the current situation of PEM electrolyzer, the key to their large - scale application lies in reducing costs and optimizing performance. At present, cost reduction can be achieved by optimizing the catalyst system to reduce costs, using highly conductive support materials, and replacing them with high - performance proton exchange membranes.

I. Cost Reduction and Optimization of PEM Electrolyzer

1. Development and Application of Low - Noble - Metal Electrocatalyst 

①　Reducing Manufacturing Costs
By reducing the content of noble metals (platinum, iridium, ruthenium) and improving the efficiency of the preparation process, the manufacturing costs of PEM electrolyzer electrocatalysts can be reduced, enhancing the market competitiveness of products.

②　Improving Stability
The stability of PEM electrolyzer electrocatalyst can be improved by adding non - metallic element doping and improving the crystal structure, making them more stable and reliable during actual use.

③　Enhancing Performance
The performance of PEM electrolyzer electrocatalysts can be enhanced by adjusting the electrocatalytic activity of non - noble metals and increasing the specific surface area, reducing the activation energy barrier of the reaction and increasing the reaction rate.

2.Design and Preparation of Highly Conductive Support Materials

①　Improving Conductivity
The conductivity of PEM electrolyzer electrocatalysts can be improved by selecting appropriate support materials and increasing the contact area between the catalyst and the support material, reducing the resistance loss during the reaction.

②　Increasing Support Strength
The support strength of PEM electrolyzer electrocatalysts can be increased by enhancing the strength and toughness of the support material and improving the preparation process, preventing the catalyst from cracking or detaching during the reaction.

③　.Adjusting the Microstructure
The microstructure of PEM electrolyzer electrocatalysts can be adjusted by regulating the microstructure of the support material and changing the transport path of reactants, further optimizing the transport and reaction processes of reactants.

3.Optimization and Improvement of Proton Exchange Membrane Structure
At present, although many domestic manufacturers are researching proton exchange membranes, most industrial - grade applications and industrial projects still rely on products from the United States and other countries. Therefore, it is very important to carry out optimization, upgrading, and transformation of proton exchange membranes.

①　.Selective Permeable Membrane
Gas permeation can be reduced by introducing a selective permeable membrane. This membrane only allows the reaction gas to pass through while blocking the permeation of other gases.

②　Sandwich Structure
Gas permeation can be reduced by changing the sandwich structure. For example, a porous cushion can be introduced to divide the PEM into multiple small regions, reducing the cross - over of gas products.

4.Gas Diffusion Coefficient
Gas permeation can be reduced by lowering the gas diffusion coefficient. This can be achieved by increasing the rigidity of the polymer chain, introducing reinforcing materials, and improving the processing conditions.

Ⅱ.Optimization of Slurry Composition and Enhancement of Physical Properties

1.Optimization of Slurry Composition
Adjust the catalyst, carrier components, ionomers, and other additional materials in the slurry according to requirements to optimize its performance.

2.Enhancement of Physical Properties
The quality of the MEA can be improved by enhancing physical properties such as the particle diameter, rheology, and Zeta potential in the slurry.

3.Introduction of Additional Functions
The lifespan and reliability of the MEA can be improved by introducing additional functions such as antioxidants and reducing agents.

Ⅲ.Improvement and Optimization of MEA Processing Technology Measures

1.Selection of Coating Methods
Select appropriate coating methods such as electrochemical deposition, ultrasonic spraying, and transfer printing according to requirements to optimize the catalytic performance of the MEA.

2.Modification of Coating Equipment
Modify the existing coating equipment according to requirements to achieve roll - to - roll coating, etc., to meet industrial demands.

3.Monitoring of Coating Film Quality
Establish a coating film quality inspection system to monitor the quality of the coating film in real - time and implement feedback control to ensure the quality of the MEA.

 

1、Understanding ion exchange membrane An ion exchange membrane (IEM) is a thin barrier that allows ions to be selectively passed from one electrode of an electrochemical device to another, including but not limited to water electrolysis cells and fuel cells. The ion-exchange membrane consists of a three-dimensional polymer matrix functionalized with charged (or ion-exchange) groups. These fixed charge groups completely or partially repel similarly charged ions (isoions) out of the membrane and allow ions with different charges (counterions) to pass through the membrane. In hydroelectrolytic cells and fuel cells, efficient ion transport is important for achieving high performance, reducing overpotential, and ensuring the overall effectiveness of relevant electrochemical processes.

2、Key considerations when choosing a appropriate IEM

According to the type of fixed charge group in the polymer backbone, IEM can be divided into two types: cationic (CEM) and anion (AEM) exchange membrane. The cation exchange membranes contain fixed negatively charged ions that allow the cations to move on the membrane. Conversely, AEM carries positively charged groups that selectively allow the transport of anions. In addition to these two basic classifications, the IEM can also be a proton exchange membrane (PEM), a bipolar membrane, an amphotropic membrane, and a mixed matrix membrane. In water electrolytic cells and fuel cells, PEM and AEM are the most useful. PEM is a special CEM that can transport protons (H + ions).

1. When choosing an ion exchange membrane, the first consideration is the type of fuel cell and water electrolytic tank. The operation of fuel cells and water electrolytic cells involves the transport of ions; the type of ion to be transmitted determines the appropriate type of ion exchange membrane to be used. Polymer electrolyte membrane water electrolytic cell (PEMWE) and fuel cell (PEMFC) operating under acidic conditions are required to transport H + ions. Thus, both PEMFC and PEMWE use the PEM. In contrast, anion exchange membrane fuel cells (AEMFC) and anion exchange membrane water electrolytic cell (AEMWE) operate in alkaline environments. Both AEMFC and AEMWE used the AEM.

Once the type of IEM suitable for the fuel cell and water electrolytic cell has is identified, it is time to go deeper into the specific characteristics that produce target efficiency and performance.

2、The IEM performance and the balance between them

In general, the properties of the IEM are determined by the characteristics of the polymer backbone and the fixed charge that constitutes its structure. In particular, the density, wettability (hydrophobic or hydrophilic) and morphology of the polymer matrix, as well as the type and concentration of charged functional groups, can affect the performance of IEM. The mechanical, chemical and thermal properties of IEM are mainly influenced by the polymer backbone, while the electrochemical properties, conductivity and overselectivity are determined by the concentration of the fixed charge. Click here to learn more about the key IEM features.

High-performance IEM shall have high ionic conductivity, high ion exchange capacity, near-uniform overselectivity, and excellent dimensional, chemical, mechanical, and thermal stability. However, it is not easy to meet all of these requirements. We can't do everything, and in most cases, we have to find the perfect balance between these features.

3. Working conditions

When finding a suitable IEM for your application, you should also consider working conditions, including temperature, pressure, and humidity levels. Working conditions can affect not only IEM performance, but also its stability. Some IEM have the best performance at high temperatures, while others are designed for low temperature applications. Ensure that the selected IEM supports the device usage environment.

4, the cost of membrane materials

Suppose that we have found a perfectly optimized membrane with both good performance and stability. Another factor to be considered is the cost. Usually, high requirements for performance and stability require high material costs. Therefore, balancing performance requirements and budget constraints is critical because the cost of IEM affects the overall cost of fuel cells and water systems.

Choosing the right ion exchange membrane is the key point in the design of efficient and durable hydrolysis cells and fuel cell systems. By carefully considering the above factors and conducting appropriate tests, you can make informed decisions based on the specific application requirements. Please contact us, our application engineers and in-house hydrolysis cell and fuel cell experts will help you select the best product for your application. Let's work together to pave the way for the development of clean and sustainable energy solutions.