Need for Speed: Fast Activation of PEM Electrolyzers for End-of-Line Testing
Authors: Rauh Julius Frederik , Höglinger Martin , Karan Benedikt , Steiner Johannes , Macherhammer Marie-Gabrielle , Trattner Alexander 
Published: December 2024

The Membrane Electrode Assembly (MEA) in a Proton Exchange Membrane Water Electrolyzer (PEMWE) requires an activation procedure (also known as initial conditioning or break-in) to reach its nominal stable performance, which can take up to several days. In large-scale industrial production of electrolyzers, this can create a bottleneck in the manufacturing process, as the functionality of each electrolyzer typically needs to be verified by activating and characterizing it in an end-of-line test.

Although several activation methods for PEMWE can be found in the literature, to the authors' knowledge, none have been published with the goal of fast activation. The existing activation protocols are usually derived from PEMFC protocols or specified by the manufacturer without any information on how they were developed [1–4].

The aim of this study is to gain a deeper understanding of the influencing factors of activation procedures in PEMWE in order to develop faster activation protocols for Begin of Life (BoL) characterization. To this end, we are conducting a Design of Experiment (DoE) parameter study in which we test different variations of galvanostatic activation protocols on PEM single cells. Each activation and characterization of a cell is followed by a short AST and a subsequent End of Life (EoL) characterization to see if the activation had an impact on degradation and final performance.

The procedure followed for each test in the activation protocol is outlined in Figure 1a. All tests are performed on fresh MEA materials in a Baltic quickCONNECT cell with an active area of 7.2 x 7.2 cm and an active area compression of 2 MPa. The MEA consists of a state-of-the-art Catalyst Coated Membrane (CCM) sandwiched between a platinized titanium felt and Toray carbon paper. After integration into the test bed, the cell is flushed with water on both the anode and cathode sides while being heated to operating temperature, which takes a total of 6 hours. Galvanostatic activation is then performed over a period of 4 hours. This is followed by BoL characterization, during which polarization curves and electrochemical impedance spectra are recorded to evaluate initial performance. The cell is then subjected to an 80 hour Accelerated Stress Test (AST) where the potential is alternated between 0 and 2 V at 10 second intervals at 80 °C cell inlet temperature. Finally, an End of Life (EoL) characterization is performed to determine the final performance.

The examined activation parameters, which are the input factors for the DoE, can be seen in Figure 1c. They are the anode inlet temperature, the maximum current density, a soft-start step (applying a lower current density of 0.2 A/cm² for the first 30 minutes), and the mode of current application (static or dynamic cycling between 100 % and 20 % of the maximum current density in 5-minute intervals). The full factorial DoE requires 16 experiments when each factor is varied between 2 states. The full test plan as seen in Figure 1b also includes 3 initial tests where the cell is activated according to the CCM suppliers' recommendation and 2 center points at the beginning and end of the full-factorial test plan. These additional tests show the reproducibility of the test results and any changes in cell performance over the duration of the test series.

Through this experimental study, we show the influence of four activation parameters (Temp, current density, soft start, and current mode) on the quality of the activation, the BoL performance, and the initial degradation rate of PEMWE. This will lead to faster activation protocols for the end-of-line testing of PEMWE and will thus help the large-scale industrial production of electrolyzers.

[1] Padgett E, Bender G, Alia SM. Membrane Pretreatment and Cell Conditioning for Proton Exchange Membrane Water Electrolysis. Meet. Abstr. 2021;MA2021-02(41):1252. https://doi.org/10.1149/MA2021-02411252mtgabs.

[2] Bender G, Carmo M, Smolinka T, Gago A, Danilovic N, Mueller M et al. Initial approaches in benchmarking and round robin testing for proton exchange membrane water electrolyzers. International Journal of Hydrogen Energy 2019;44(18):9174–87. https://doi.org/10.1016/j.ijhydene.2019.02.074.

[3] Wang W, Li K, Ding L, Yu S, Xie Z, Cullen DA et al. Exploring the Impacts of Conditioning on Proton Exchange Membrane Electrolyzers by In Situ Visualization and Electrochemistry Characterization. ACS Appl Mater Interfaces 2022;14(7):9002–12. https://doi.org/10.1021/acsami.1c21849.

[4] Tomić AZ, Pivac I, Barbir F. A review of testing procedures for proton exchange membrane electrolyzer degradation. Journal of Power Sources 2023;557:232569. https://doi.org/10.1016/j.jpowsour.2022.232569.

Figure 1