The role of water on the electrochemical properties of an IL in contact with an electrode, in general, has been studied previously. These studies often focus on the distribution of water at the solid | electrolyte interface as well as in the bulk electrolyte and on the electrochemical stability window of the IL. A few of the latter studies did show the emergence of features similar to peaks C1 or C3 in type I observed in the present work. In order to address the influence of water, we would briefly comment on the different water sources in such measurements and how they would impact the overall behaviour. A less commonly addressed origin is the native water film that develops on an electrode surface following its preparation, typically occurring during the transfer to the electrochemical cell, often located within a glove box. In this case, the amount of water on the surface should be rather similar for all experiments. Assuming that the water reacts on the substrat e when a potential is applied, the related current response should possibly be small and only visible within the first potential cycle. This phenomenon could at least to some extent rationalise the observed changes of the CV within the first potential cycles in our experiments (see Figure ).