Phase Separation in Mixed Ionic and Electronic Conductors for Information Storage

Mixed ionic and electronic conductors (MIECs) enable vast changes in chemical composition induced by electrochemical currents and voltages. This electrochemically-induced change in chemical composition enables a substantial chemical capacitance, which can be harnessed for energy storage and emerging microelectronic devices. This change in composition can yield phase transformations and spinodal decomposition in MIEC materials due to materials thermodynamics. In this presentation, we show how this phase separation in metal oxide MIECs enables the coexistence of multiple physical states that are identical in energy. By switching between these physical states, we can provide a thermodynamically nonvolatile form of information storage. We demonstrate this phenomenon in two types of memory cells: resistive memory and electrochemical memory. We anticipate that phase separation can be broadly generalized to other forms of MIECs.