Why must an electrochemical cell form a closed electrical loop?

An electrochemical cell must form a closed electrical loop to allow for the continuous flow of electricity, which is essential for the cell's operation.1

In an electrochemical cell, the overall process is a redox reaction where reduction and oxidation occur at spatially separated electrodes. For these reactions to proceed, electrons must be able to move through the system: if electrons are released into a metal at one interface (oxidation), there must be a corresponding interface where electrons are consumed (reduction).1

Because electric charge is conserved, the system cannot function if the circuit is open, as the accumulation of charge would prevent further reaction. By forming a closed loop, the cell ensures that the rate of electron flow—measured as electric current density—is maintained, allowing the transfer of electrons between the chemical species and the electrodes to continue.123