where 𝜎 𝑠,𝑒𝑓𝑓 is the effective electronic conductivity for the electrode; F is the Faraday's constant; j is the local current flux between electrodes and liquid electrolyte; x is the length along the thickness direction of the electrode; F is the surface area for electrode particles. For a, it is the surface area for electrode particles (for Li-S battery, only sulfure particles considered) and its relationship with radius of electronde particle size R and its volume fraction 𝜖 𝑠 within electrode is shown in equation ( ):