Newman and Tobias 23 derived a description of reaction current distributions through the electrode in one dimension. In the one-dimensional approximation, the current densities and reaction rates are only a function of the relative position 𝑥 in the electrode located between the separator (𝑥 = 0) and the current collector (𝑥 = 𝐿) interface (schematically shown in Figure , left). The electronic current density ie in the active material and ionic current density iion in the electrolyte are described by Ohms law: 𝑖 ! = -𝜎 ! d𝜑 "# d𝑥 and 𝑖 $%& = -𝜎 $%& d𝜑 '( d𝑥 , Eq. 1