At the start of anodic charging (Fig. , stage 3 to 4), desorption of THA + cations occurs and is accompanied by loss of solvent molecules. This leads to a pronounced observed mass loss in this region (Fig. ). However, as anodic charging continues and more desorption of large THA + cations from the MOF pores occurs, the amount of free in-pore volume significantly increases. As a result, solvent molecules can feed back into the electrode pores from the bulk electrolyte as cation desorption continues (Fig. ; stage 4 to 1). This leads to a gradual reduction in the slope of the Δm-ΔQ plot in this region (Fig. ). Due to this phenomenon, there is a corresponding improvement in ion kinetics between stages 4 and 1, evidenced by the increased anodic current in this region (Fig. ). However, as for TEA + , the possibility of anion involvement in the charging mechanism with THA + cannot be fully ruled out as EQCM gives only a net mass change and cannot distinguish between different species.