To delve into the difference of these resultful additives, a plot of the onset shift as a function of corresponding anion radius is shown in Figure (see Figure for the confirmation of onset potential). A nearly linear decrease of the onset shift with increased anion radius highlights the importance of ion size in adsorption. As for the abnormal trend of LiClO4, specific adsorption (normally occurs in the IHP ) rather than electro-adsorption may account for its interfacial as well as electrochemical behavior. Combined with results of competitive adsorption in the presence of LiI, we can therefore reach four requirements for additive selection/design that should be simultaneously met: