Hydrogen can be used as a clean and renewable green energy, and Proton Exchange Membrane water electrolysis (PEMWE) to produce hydrogen is one of the main methods for hydrogen production. The technology uses the proton exchange membrane (PEM) as a solid electrolyte to replace the alkaline electrolyte and diaphragm, and uses pure water as the electrolyte.
In the PEM water electrolysis hydrogen production device, the membrane electrode composed of the diffusion layer (Gas Diffusion Layer, GDL), the catalytic layer and the proton exchange membrane is the main place for the electrochemical reaction of the electrolytic cell, and is the core component of PEMWE.
The Gas diffusion layer(GDL) not only has the functions of supporting the Catalyst Coated Membrane (CCM), evenly distributing the reaction water, and discharging the generated gas in time, but also can realize functions such as conducting current, and is one of the key components affecting the performance of the electrolytic cell.
A good diffusion layer material should have the following characteristics:
1) Good electrical and thermal conductivity, the contact resistance between the electrode catalysts can be kept at a low level to reduce the electrolysis overpotential;
2) Strong acid corrosion resistance, the diffusion layer of the anode should have good resistance to oxidation corrosion in order to overcome the long-term contact oxygen evolution reaction, while the cathode
The extremely diffusion layer should be resistant to hydrogen embrittlement in order to overcome the long-term exposure to hydrogen evolution reaction;
3) Porous and elastic, since the diffusion layer is close to both sides of the membrane electrode and plays a supporting role for the membrane electrode, it can withstand a certain pressure;
4) Long service life and cheap price.
In the comparison of titanium fiber felt, sintered titanium plate and carbon paper as anode diffusion layer, it is found that titanium fiber felt has the best electrolytic performance, the smallest ohmic resistance and good stability, so titanium fiber felt is more suitable as the anode diffusion layer of PEMWE.
★Uniform pore size distribution,
★strong corrosion resistance,
★good water permeability,
★ good heat dissipation
★ high current density,
★ stable performance and long service life.