We use specific notation to distinguish between fitness values with ( Ŵ ) and without (W ) the voltage shift. Analogously to Eq. 5, with the inclusion of the voltage shift, the modified current constraint f a i a (ϕ s,a + ∆ϕ) = -f c i c (ϕ s,c + ∆ϕ) holds. This equation is solved implicitly to determine the value of the voltage shift. Once the voltage shift is determined, the fitness W can then found by ensuring equality of the fitness values between the cathode and anode in the full cell as