A cylindrical 8 mm diameter piezoelectric transducer was used to collect acoustic emission data (Nano30, Mistras NDT, U.K.) with an operating frequency range of 125-750 kHz. Good contact between the transducer and the Pyrex body of the electrolyser was ensured through the use of high-temperature acoustic couplant (Couplant H-2, Olympus, Japan). The transducer was placed over the center top part of the current collection plate and held in place with electrical tape. The transducer was connected to a 1283 USB AE node acoustic emission system (MISTRAS, U.S.) with the data collected and analyzed using AEwin software (MISTRAS, U.S.). A noise threshold of 25 dB was used for all data collection to distinguish between background noise and what was classified as an acoustic hit. The high acoustic impedance of the EPDM gasket between the two halves of the cell allows for the acoustic behavior of the anode and cathode to be decoupled to some extent and the electrode under study selected by swapping the side of the cell that the transducer is in contact with. Tests were repeated with no couplant and a small distance between the sensor and the body of the cell. These tests gave no acoustic hits, confirming that any signals observed while the test was running were not due to any potential electromagnetic interference. Table . Selected room temperature (23 o C) performance metrics of the cell in Figure .