Assessing the performance of gold-coated titanium bipolar plates in proton exchange membrane water electrolysis under variable photovoltaic inputs

Given the anticipated growth of the green hydrogen economy, revealing the degradation features of proton exchange membrane water electrolysis (PEMWE) under fluctuating renewable energy loads is essential. However, many studies aimed at exploring the characteristics of catalysts and membranes under various loads have neglected the study of bipolar plate materials under fluctuating loads observed in realistic scenarios. This study investigated the electrochemical behavior and failure mechanism of Au coating on TA1 titanium bipolar plates in the simulated anode environment of PEMWE, especially under fluctuating loads. We simulated accelerated voltage fluctuation based on minute-level data measured by photovoltaic power stations in typical new energy enrichment areas in northwest China. The influence of different fluctuation frequencies on the electrochemical corrosion and conductivity of Au-coated TA1 was discussed. The results showed the electrochemical anode process of Au-coated TA1 was more sensitive to fluctuation frequency. The voltage fluctuation load changed the film structure on the surface of TA1 and Au-coated TA1, thereby affecting the electrochemical behavior. Further, this study revealed the impact of accelerated voltage fluctuations on interfacial contact resistance. The Au(OH)3 content increased with higher fluctuation frequency, leading to the Au consumption and a decrease in conductivity. When the frequency of accelerated voltage fluctuation increases from 0 cycles to 120 cycles, although the passive current density rapidly decreases, it can still cause serious damage to the Au coating, resulting in an increase in interfacial contact resistance to 10.48 m Omega & sdot;cm2. These insights underscore the critical role of voltage fluctuation conditions in PEMWE durability, offering strategic guidance for designing metal bipolar plates to enhance the longevity and performance of hydrogen production components in renewable energy applications.