US Patent 10186657 Three-terminal metastable symmetric zero-volt battery memristive device

A method of fabricating a memristive structure for symmetric modulation between resistance states is presented. The method includes forming a first electrode and a second electrode over an insulating substrate, forming an anode contacting the first and second electrodes, forming an ionic conductor over the anode, forming a cathode of the same material as the anode over the ionic conductor, forming a third electrode over the cathode, and enabling bidirectional transport of ions between the anode and cathode resulting in a resistance adjustment of the memristive structure, the anode and the cathode being formed from metastable mixed conducting materials with ion concentration dependent conductivity.