A medical electrode assembly includes an electrically conductive electrode, an electrically conductive sacrificial element, and a layer of electrically conductive gel. The electrode has an electrical terminal to connect with external electrical circuitry. The sacrificial element is electrically connected with the electrode through an impedance element or a power supply. The layer of electrically conductive gel contacts both the electrode and the sacrificial element so as to form an anode-cathode cell in which the sacrificial element functions as a sacrificial anode that corrodes and the electrode functions as a cathode that is protected from corrosion.