The measurement cell as illustrated in Figure ) was designed in a way that it is comparable to other commonly used research cells like Swagelok® type cells or coin cells. The distance between the working and counter electrodes has also been reduced to minimize the electrolyte volume, which is a common limitation of many DEMS cells. . A drawback of commonly used coin or Swagelok-type cells is the small electrode size in the range of ~1 cm 2 . The smaller the electrodes, the less gas is formed and the more difficult it is to reach the detection limit of the MS. We therefore use larger working electrodes (11.24 cm 2 ) to improve the MS signal-to-noise ratio in this study.