The nonlinear mechanism of Mn oxide-catalyzed water electro-oxidation reaction was investigated in search of novel strategies toward highly efficient industrial oxygen evolution reaction under high concentration and large current. The periodic potential oscillation under constant-current electrolytic condition was observed for the first time in the process of Mn oxide-catalyzed water electro-oxidation at a large current density. Taking advantage of the oscillation, the energy consumption was reduced by 10.9% as a results of an average potential drop of 0.28 V at a current density of 0.3 A/cm(2). A possible oscillation mechanism was proposed based on the influence of anode material, current density, [Mn2+], and Mn oxide structure. Nonlinear dynamical equations for constant-current condition were analyzed considering the time-varying kinetic parameters that differ from the kinetic constants under constant-voltage condition, in order to provide insights into the catalytic effect of the Mn(III) species and the critical parameters during oscillation. It is possible for the oscillation to be further enhanced by a more suitable external electric field, which suggested a potential strategy toward highly efficient industrial OER technologies with low electrolytic energy consumption at large current. (C) 2017 The Electrochemical Society. All rights reserved.