Evaluation of nitrided titanium separator plates for proton exchange membrane electrolyzer cells

Abstract

Proton exchanges membrane (PEM) regenerative fuel cell electrolysis of water is of great recent interest as a hydrogen generation technology. Anode side titanium current collectors and separator plates used in these applications typically employ coatings of platinum group metals to achieve durability and performance requirements in the high voltage, oxidizing environment. The present work assessed the potential for lower cost surface modified titanium by both thermal (gas) nitridation and plasma nitridation approaches. The nitrided Ti was found to result in far less hydrogen uptake in coupon testing than did Pt-plated Ti. Short-term (48 h) single-cell performance at 25 °C was approximately 13% better (lower voltage) at 1.2 A/cm 2 for thermal and plasma nitrided plates vs untreated Ti. However, at 50°C and 1.5 A/cm 2 , the thermally nitrided plate exhibited only on the order of 3% better behavior (lower voltage) compared to the untreated Ti and plasma nitrided Ti. Durability testing for 500 h resulted in only a minor degradation in cell performance, on the order of 1-2% voltage increase, with the best behavior exhibited by the thermally nitrided Ti plate. Despite their relatively stable cell performance, extensive local oxidation of the thermally nitrided and plasma nitrided flow field regions was observed.

Electrochemical performance modeling of a proton exchange membrane electrolyzer cell for hydrogen energy

“…Voltage difference 3.55e À8 Water density, (g/cm 3 among different temperatures will become large with increasing current density. At a current density of 0.5 A/cm 2 , the voltage difference between 40 and 80 C is 0.02 V, while at a current density of 2.0 A/cm 2 , the voltage difference amounts to 0.08 V. Similar conclusions have been confirmed with recent experimental results [14]. Fig.…”

Estimating future costs of power-to-gas – a component-based approach for technological learning

“…In this regard, the classifications for PEMEC and AEC are primarily based on data by E4tech [45] and Smolinka, et al [46] & [11], since they also provide cost structure data. This component structure is, on the whole, comparable to data and descriptions available in other literature about PEM cell stack technology, be it electrolysis [10,[47][48][49] or fuel cell [18,50,51]. Compared to AEC and PEMEC, solid oxide electrolysis cells are an emergent technology that is expected to reach high current densities at elevated operating temperatures and appropriate integrated heat management [40,52,53], making an investigation within this study reasonable.…”

Discovery of true electrochemical reactions for ultrahigh catalyst mass activity in water splitting

“…Although PEMECs have been in use for decades, there are still several significant challenges before they can be widely applied in hydrogen/oxygen production, including cost, durability, and efficiency ( 17 , 19 – 21 ). PEMECs use a proton exchange membrane (PEM) as the electrolyte, which permits proton transport from anode to cathode, and typically, IrRuO x and Pt/B are used as the anode and cathode catalysts, respectively.…”