• Journal of the Korean Electrochemical Society
• /
• v.26 no.2
• /
• pp.19-34
• /
• 2023

Due to the intermittency of renewable energy sources, a need to store and transport energy will increase. Hydrogen production through water electrolysis will provide an excellent way to supplement the intermittency of renewable energy sources. While alkaline water electrolysis is currently the most mature technology, it has drawbacks of low current density, large footprint, gas crossover, etc. The PEM water electrolysis has potential to replace the alkaline electrolysis. However, expensive catalyst material used in the PEM electrolysis has been the bottleneck of widespread use. In this review, we have reviewed recent efforts to reduce catalyst loading in PEM water electrolysis. In core-shell nanostructures, the precious metal catalyst forms a shell while heteroatoms form a core. In this way, the catalyst loading can be significantly reduced while maintaining the catalytic activity. In another approach, a corrosion-resistant support is utilized, which provides a stable platform to impregnate precious metal catalyst.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.254-256
• /
• 2009

The performances of proton exchange membrane (PEM) water electrolysis depend on many factors such as materials, geometries, fabrication methods, operating conditions, and so forth. The fabrication method is concerned, membrane electrode assemblies (MEA) are a most important part to show different performances by different fabrication methods. The performance change of PEM water electrolysis was experimentally measured according to the fabrication differences of the anode electrodes. One point of view is the catalyst intrusion rate to the anode gas diffusion layer (GDL), and the other point of view is the catalyst loading distribution in depth of the anode GDL. Results show that the performances of MEA with deep intrusion of the catalysts are better in the range of low current densities but worse at higher current densities. The catalyst loading distribution does not affect significantly to the performance of PEM water electrolyser.

• New & Renewable Energy
• /
• v.5 no.4
• /
• pp.75-78
• /
• 2009

The performances of proton exchange membrane (PEM) water electrolysis depend on many factors such as materials, geometries, fabrication methods, operating conditions, and so forth. The fabrication method is concerned, membrane electrode assemblies (MEA) are a most important part to show different performances by different fabrication methods. The performance change of PEM water electrolysis was experimentally measured according to the fabrication differences of the anode electrodes. One point of view is the catalyst intrusion rate to the anode gas diffusion layer (GDL), and the other point of view is the catalyst loading distribution in depth of the anode GDL. Results show that the performances of MEA with deep intrusion of the catalysts are better in the range of low current densities but worse at higher current densities. The catalyst loading distribution does not affect significantly to the performance of PEM water electrolyser.

• Korean Chemical Engineering Research
• /
• v.61 no.1
• /
• pp.19-25
• /
• 2023

Although a lot of research and development has been conducted on the performance improvement of PEM (Proton Exchange Membrane) water electrolysis, the research on durability is still in early stage. This study investigated effect of temperature on the water electrolysis durability when driving temperature of the PEM water electrolysis was increased to improve performance. Voltage change, I-V, CV (Cyclic Voltammetry), LSV (Linear Sweep Voltammetry), Impedance, and FER (Fluoride Emission Rate) were measured while driving under a constant current condition in a temperature range of 50~80 ℃. As the operating temperature increased, the degradation rate increased. At 50~65 ℃, the degradation of the IrO₂ electrocatalyst mainly affected the durability of the PEM water electrolysis cell. At 80 ℃, the polymer membrane and electrode degradation proceeded similarly, and the short resistance decreased to 1.0 kΩ·cm² or less, and the performance decreased to about 1/3 of the initial stage after 144 hours of operation due to the shorting phenomenon.

• Korean Chemical Engineering Research
• /
• v.61 no.2
• /
• pp.202-207
• /
• 2023

In the case of driving water electrolysis by receiving surplus electricity from solar and wind power generation, operation and stopping must be repeated according to weather fluctuations. When the PEMWE(Polymer Electrolyte Membrane Water Electrolysis) is driven and stopped, the PEM fuel cell is in the same state as the PEM fuel cell due to the residual hydrogen and oxygen, and the high potential of the water electrolysis formed during operation is highly likely to cause degradation of the electrode and membrane even during stopping. In this study, in order to check how much degradation of the electrode and membrane progresses during the repeated driving/shutdown process of PEM water electrolysis, the performance decrease was measured by changing the number of driving/shutdown for 144 hours. Changes in electrode catalyst active area, hydrogen permeability and fluorine emision rate of membranes were analyzed to measure changes in the properties of electrodes and polymer membranes. Overall, the PEMWE performance decreased as the number of stops increased. When stopped 5 times in 144 hours, the IrO_x catalyst activity decreased by more than 30%, and the hydrogen permeability increased by 80%, confirming that both the electrode and the membrane were deteriorated.

• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.3
• /
• pp.231-237
• /
• 2017

With worldwide efforts to increase the portion of renewable energy for $CO_2$ reductions, a lot of attention has been paid to P2G (power-to-gas) in Europe and Japan to efficiently utilize the surplus electricity. In this paper, economic feasibility analysis has been carried out for P2G using PEM water electrolysis by reflecting current economic status in Korea. In addition, efficiency and electricity price required to be competent in Korean market were provided. Based on cash flow diagrams, unit production costs for $H_2$ and $CH_4$ were estimated and profitability of P2G using PEM water electrolysis was analyzed.

• Journal of the Korean Institute of Gas
• /
• v.23 no.6
• /
• pp.33-38
• /
• 2019

In order to invigoration the hydrogen economy, production of hydrogen needed for hydrogen charging stations and hydrogen fuel cells is needed. Generally, it is reforming used to coal fuel or natural gas. Other technologies include water electrolysis using pure water. Among these water electrolysis technologies, development is mainly carried out using PEM(Polymer Electrolyte Membrane electrolysis). In this study, the company aims to identify potential harmful hazards to PEM electrolysis hydrogen stations in the development stage among hydrogen charging stations. In order to find the hazardous factors in the facilities of the electrolysis and hydrogen charging stations, we were analyzed by Failure Mode & Effect Analysis(FMEA).

• Journal of the Korean Institute of Gas
• /
• v.28 no.1
• /
• pp.65-72
• /
• 2024

Green Hydrogen demonstration complex is under conduction in Jeju island which is rich in renewable energy resources and will produces green hydrogen using a water electrolysis systems. In order to check durability of long-term operation, AST(accelerated stress test) was applied and the power pattern based on Jeju Island's wind power was applied. After 800 hours of repeated application of low current and high current, the performance of the PEM water electrolysis cell was reduced by up to 10% and by about 5.5% in operating conditions. As the result of impedance analysis, it can be seen that the electrode polarization resistance greatly increased than ohmic polarization resistance. In addition, when the durability evaluation was conducted by applying the wind power pattern of Jeju Island, the performance of the PEM water electrolysis cell showed up to 1.6% and a decrease of less than 1% in operating conditions. As a result of the impedance, it can be seen that the change of ohmic resistance and electrode polarization resistance is small.

• Journal of the Korean Electrochemical Society
• /
• v.26 no.4
• /
• pp.56-63
• /
• 2023

The development of renewable energy technologies, such as solar, wave, and wind power, has led to the diversification of water electrolysis technologies, which can be easily coupled with renewable energy sources in terms of economics and scale. Water electrolysis technologies can be classified into three types based on operating temperature: low-temperature (<100 ℃), medium-temperature (300-700 ℃), and high-temperature (>700 ℃). It can also be classified by the type of electrolyte membrane used in the system. However, the concepts of thermodynamic and thermo-neutral voltages calculations and are very important factors in the evaluation of energy consumption and efficiency of water electrolysis technologies, are often confused. This review aims to contribute to a better understanding of the calculation of operating voltage and efficiency of PEM water electrolysis technologies and to clarify the differences between thermodynamic voltage and thermo-neutral voltage.

• Membrane Journal
• /
• v.32 no.5
• /
• pp.275-282
• /
• 2022

In contemporary days, hydrogen-based energies including batteries are renowned to be effective. And its effectiveness comes from the fact that it possesses high efficiency as an energy carrier. Eco-friendly and high purity of hydrogens comes out from water electrolysis. And among different types of electrolysis, proton exchange membrane (PEM) water electrolysis is considered the most renewable, cheap, and eco-friendly. It produces oxygen and hydrogens which are feasible in using as energies. Since it has such a number of benefits, increased research is going on in PEM electrolysis. Nafion is widely used as PEM, but high cost and various other disadvantages leads to the exploration of alternative materials. This review is broadly classified into Nafion and non Nafion based PEM for water electrolysis.