Governing Parameter of Peak Currents in Square-wave Voltammetry Finally Identified

In square-wave voltammetry (SWV), the dependence of peak current on multiple experimental and kinetic parameters has long hindered the formulation of a Randles–Ševčík–type relationship. In this work, we demonstrate that the magnitude of peak currents can be governed by a single dimensionless parameter, defined as: JKG = constant x [dE·F/(RT)]·(Esw/dE)¹ᐟ²·[K/(1+K)]

This parameter integrates the effects of potential step, square-wave amplitude, temperature, and kinetic dimensionless parameter K (defined as K = ks (Df)^-0.5) into a unified descriptor JKG (from the initials of Janeva-Kokoskarova-Gulaboski).
Simulations and theoretical analysis show that, when JKG is held constant, peak currents remain invariant across wide kinetic regimes and large ranges of temperatures, if the ratio Esw/dE is kept constant. The proposed formulation provides a fundamental basis for simplified interpretation of SWV responses and establishes a pathway toward a generalized theoretical framework, in which also the effect of electron transfer coefficient alpha (now hidden in the “constant”) will be taken into account.