In experiments performed under thermodynamic equilibrium between the connections and working electrode, it is guaranteed that the electrochemical potentials of the system and bath are equal to the Fermi level (μ M e = μbath e = E F ) because both M and bath phases are explicitly present (see Figure ). Because the two chemical potentials and Fermi level must be equal under equilibrium, equation ensures that the experimentally specified electrode potential corresponds to inner potential changes within either the bulk phase M or bath. This in turn means that changes in the bath inner potential (∆ϕ bath ) uniquely defines the response of the system inner potential (∆ϕ M ) in equilibrium because both potentials are inherent bulk properties; it follows that the applied electrode potential directly modifies