Overview
This research examines the degradation characteristics of proton exchange membrane water electrolyzers (PEMWE) when subjected to fluctuating power supplies. The investigation utilized accelerated stress test (AST) protocols involving dynamic load cycling. Key parameters, specifically peak voltage and cycling frequency, were analyzed to understand their impact on PEMWE degradation. The study established relationships between the structural properties of the catalyst layer and the observed electrochemical performance.
Research Context
Proton exchange membrane water electrolysis is a technology considered for integrating intermittent renewable energy sources. Such applications inherently involve dynamic operational conditions, which necessitate an understanding of system degradation under fluctuating loads. This study addresses this by employing ASTs designed to emulate features of dynamic load fluctuations encountered with variable renewable energy operation.
Approach
The research involved an experimental investigation of PEMWE degradation. The experimental setup employed dynamic load cycling under AST conditions. The study systematically varied two specific parameters: the peak voltage and the cycling frequency. These variations were applied within simplified AST protocols. The analysis focused on monitoring electrochemical performance and correlating it with the structural characteristics of the catalyst layer.
Findings
- An elevated peak voltage accelerated the degradation of PEMWE during the initial phase of the accelerated stress test.
- A low cycling frequency mitigated the overall degradation. This mitigation was attributed to the limitation of increases in various forms of resistance within the electrolyzer.
- Conversely, a higher cycling frequency exacerbated the degradation. This enhanced degradation was primarily associated with an increase in mass transport resistance.
- The findings suggest a frequency-sensitive deterioration of the system's components, indicating that the impact of cycling frequency on degradation mechanisms differs from that of peak voltage.
- The study unveiled an intricate relationship between the structural characteristics of the catalyst layer and the electrochemical performance of the PEMWE system.