Abstract
Degradation analysis of proton exchange membrane (PEM) water electrolyzers is crucial for evaluating their long-term durability and performance in realistic operation scenarios1. This study investigates the fluoride emission rate (FER) as a key parameter during various accelerated stress tests (ASTs). The objective is to assess the effects of different stressors on PEM electrolyzers, providing insights into their degradation mechanisms and potential mitigation strategies.
Results from three distinct degradation studies were collected: (1) Photovoltaic (PV)- electrolyzer direct coupling2, (2) Induced H2-crossover at high temperature3 and (3) Chloride (Cl−) contamination4. The FER was quantified under each test using a novel photometric detection method5. The results indicate a strong correlation between the applied stressors and the FER, with variations observed depending on the specific test conditions.
During PV-operation a loss of ionic conductivity due to periods of OCV hold resulted in a ~50 % higher FER (0.44 compared to 0.22 μg h−1 cm−2) at the cathode and a 66 % higher FER (0.18 to 0.06 μg h−1 cm−2) at the anode compared to a reference experiment2. A direct correlation between the FER and H2 crossover was identified in an induced H2 crossover AST performed at 80 °C and 60 °C. High-temperature operation led to a pronounced rise in FER (0.78 μg h−1 cm−2 at 80 °C compared to 0.27 μg h−1 cm−2 at 60 °C), suggesting increased degradation rates at elevated temperatures3. 10 ppm chloride in the electrolyzer feed exhibited intermittent variations in the FER: while the value at the cathode remained constant, the anode compartment experienced a notable 4-fold rise in FER compared to reference conditions (0.36 μg h−1 cm−2 for the reference test compared 1.44 μg h−1 cm−2 for the contamination experiment)4.These findings underscore the importance of considering the FER as a sensitive indicator of PEM electrolyzer degradation and provide valuable insights into the underlying stress-induced processes, revealing it as a critical parameter. Monitoring of the FER can therefore serve as an early warning system for assessing the health and longevity of PEM water electrolyzers in various operation scenarios.
Results from three distinct degradation studies were collected: (1) Photovoltaic (PV)- electrolyzer direct coupling2, (2) Induced H2-crossover at high temperature3 and (3) Chloride (Cl−) contamination4. The FER was quantified under each test using a novel photometric detection method5. The results indicate a strong correlation between the applied stressors and the FER, with variations observed depending on the specific test conditions.
During PV-operation a loss of ionic conductivity due to periods of OCV hold resulted in a ~50 % higher FER (0.44 compared to 0.22 μg h−1 cm−2) at the cathode and a 66 % higher FER (0.18 to 0.06 μg h−1 cm−2) at the anode compared to a reference experiment2. A direct correlation between the FER and H2 crossover was identified in an induced H2 crossover AST performed at 80 °C and 60 °C. High-temperature operation led to a pronounced rise in FER (0.78 μg h−1 cm−2 at 80 °C compared to 0.27 μg h−1 cm−2 at 60 °C), suggesting increased degradation rates at elevated temperatures3. 10 ppm chloride in the electrolyzer feed exhibited intermittent variations in the FER: while the value at the cathode remained constant, the anode compartment experienced a notable 4-fold rise in FER compared to reference conditions (0.36 μg h−1 cm−2 for the reference test compared 1.44 μg h−1 cm−2 for the contamination experiment)4.These findings underscore the importance of considering the FER as a sensitive indicator of PEM electrolyzer degradation and provide valuable insights into the underlying stress-induced processes, revealing it as a critical parameter. Monitoring of the FER can therefore serve as an early warning system for assessing the health and longevity of PEM water electrolyzers in various operation scenarios.
| Original language | English |
|---|---|
| Publication status | Published - 11 Dec 2023 |
Keywords
- PEM Water Electrolysis
- Hydrogen
