Here, q represents the ionic charge of Cs + , which is the same for all ramping steps, and f is the coefficient of friction, which will be largely affected by the cation/anion surroundings and the hydration of the medium they move within. Interestingly, although these slopes align with the increased cell voltages of 2.8, 3.0, and 3.4 V, respectively, they do not have linear dependence between (u & E). This result indicates a non-linear relationship between the cell voltage and electric field or additional factors to change the friction coefficient at varying operation conditions, such as H2O content. In addition, a cyclic voltammetry experiment was also measured, as shown in Figure , where a linear change in cell voltage results in a quadratic change in Cs + and H2O intensity. From our perspective, further understanding of the Cs + dynamics requires additional modelling, which is beyond the scope of this work.