The electrochemically critical parameters in the Li–S battery, the overpotential (ΔV), the capacity from the dissolution region (Q 1), and the capacity from the precipitation region (Q 2), are identified to trace the electrochemical behavior of the electrode during the charge/discharge operation, which can aid in the deep understanding of the enhancement mechanism in the various model systems. The effects of cycling rate, conductive additive content, and oxygen functional group on the battery performance have been studied as the model systems. In this study, it is suggested that critical parameters should be carefully analyzed when exploring the performance of Li–S battery or designing batteries based on a new concept or novel architecture.