Exploring MEA membrane electrodes: a cutting-edge journey in preparation and application

 

In the era of rapid technological development, membrane electrodes, as a key functional material, have shown great potential for application and development in many fields. From new energy to environmental protection, from medical to industrial production, membrane electrodes are changing our way of life and production with their unique properties and functions.

Membrane Electrode Assembly (MEA) is a functional integrated component that combines components such as catalyst, proton exchange membrane, and gas diffusion layer. It is like a microscopic "reaction factory" that plays a central role in electrochemical processes, efficiently achieving the conversion of substances and the transfer of energy.

Preparation process of membrane electrode

1) Catalyst Coating Method (CCM Method)

This is a relatively common preparation method. Firstly, the catalyst is made into a uniform slurry, and then the slurry is coated on the surface of the proton exchange membrane through spraying, printing, and other methods. The advantage of this method is that the process is relatively simple and easy to mass produce. However, it also has some shortcomings, such as the weak binding force between the catalyst and the membrane, which can easily lead to catalyst detachment during long-term use. In order to overcome these problems, researchers continuously optimize the formulation and coating process of the slurry, and improve the bonding stability between the catalyst and the membrane.

2) Hot pressing method abbreviated as GDE method

The hot pressing method is to stack the catalyst layer, proton exchange membrane, and gas diffusion layer in sequence, and then perform hot pressing treatment at a certain temperature and pressure to tightly bond the layers. This method can make the structure of the membrane electrode more compact, improving the performance and stability of the electrode. However, the temperature, pressure, and other parameters during the hot pressing process have a significant impact on the performance of the membrane electrode and require precise control. In addition, the equipment cost of the hot pressing method is relatively high, and the production efficiency is relatively low.

3) In situ growth method (3D printing)

The in-situ growth method involves directly growing a catalyst layer on the surface of a proton exchange membrane. This method can form a tight chemical bond between the catalyst and the membrane, improving the utilization rate of the catalyst and the performance of the electrode. Compared with traditional methods, in-situ growth method can better control the particle size, distribution, and morphology of catalysts, thereby optimizing the performance of membrane electrodes. However, the preparation process of this method is relatively complex and requires high experimental conditions.

The wide application of membrane electrodes

1) Fuel cell field

A fuel cell is a device that directly converts chemical energy into electrical energy, with advantages such as high efficiency and cleanliness. As the core component of fuel cells, the performance of membrane electrodes directly affects the efficiency and lifespan of fuel cells. In proton exchange membrane fuel cells, membrane electrodes can promote the electrochemical reaction between hydrogen and oxygen, converting chemical energy into electrical energy. With the rapid development of new energy vehicles, the demand for high-performance membrane electrodes in fuel cell vehicles is increasing day by day. High performance membrane electrodes can improve the power density and energy conversion efficiency of fuel cells, extend the range of automobiles, and promote the development of the fuel cell vehicle industry. For example, the Toyota Mirai second-generation MEA has a power density of 4.4kW/L

2) In the field of hydrogen production through electrolysis of water

Electrolysis of water for hydrogen production is a sustainable method that can electrolyze water into hydrogen and oxygen. Membrane electrodes play a crucial role in the electrolysis of water, as they can reduce the overpotential of the electrolysis reaction and improve electrolysis efficiency. By using high-performance membrane electrodes, the cost of hydrogen production can be reduced, and the yield and purity of hydrogen can be improved. This is of great significance for promoting the large-scale application of hydrogen energy and achieving clean energy transformation. For example, alkaline electrolysis cell: nickel based catalyst MEA, efficiency 75%~80%, PEM electrolysis cell: iridium catalyst MEA, efficiency>85%.

3) Medical field

In neurosurgery, membrane electrode technology combines electrode grids and LEDs to track and generate real-time brain activity images during surgery, helping neurosurgeons visualize information about the patient's brain, monitor their brain status, and ultimately be used to treat brain lesions such as tumors and epileptic tissues.

4) Visual membrane electrode device

The visualized membrane electrode device consists of an insulating protective plate, a conductive bipolar plate, a silicone gasket, etc. It has the advantages of small footprint, low ohmic resistance, and fast gas/liquid transmission, and is suitable for industrial application. This device can be used in conjunction with high-speed cameras to observe the impact of escaping bubbles on the electrode surface interface with higher resolution under operating conditions; It can also be used in conjunction with Raman spectroscopy to determine the active components at the electrode surface interface under operating conditions; It can also be used in conjunction with X-ray absorption spectroscopy to identify the oxidation state, bond length, and coordination number of electrode interface elements under working conditions; It can also be used in conjunction with UV visible spectrophotometer/diffuse reflectance spectroscopy to monitor the real-time deposition/dissolution status of metal elements in the electrolyte and the coordination status of metal ions at the electrode interface under working conditions.

From laboratory to industrialization, membrane electrode technology is reshaping the global energy landscape. With material innovation and manufacturing upgrades, this technology will become a key driver for achieving the "dual carbon" goal. The future is here - the green energy revolution driven by membrane electrodes is changing the way the world provides energy. Membrane electrodes will play an important role in more fields and make greater contributions to promoting technological progress and social development.