Self-Powered Phase Transition Driven by Triboelectric Nanogenerator

The phase transition of SrCoO 2.5 (BM-SCO) is very popular in recent reports based on its special structure. The oxygen vacancy channel of BM-SCO provides a convenient condition for phase transformation to SrCoO 3-δ (PV-SCO), with prospects in smart windows, memristive devices, and magnetic recording. The traditional method for phase transition is thermal annealing, while the electric-field-controlled ionic liquid (IL) gating is also a convenient method. Herein, we use a triboelectric nanogenerator as a self-powered system, which can provide a constant voltage for the IL and achieve ion injection to induce phase transition, and this procedure proved to be reversible. X-ray diffraction scanning and high-resolution transmission electron microscope observation showed that the crystal structures of the two phases are significantly different. Besides, BM-SCO is antiferromagnetic, PV-SCO is ferromagnetic, and the optical transmittance also changes during the phase transition. As for the applications of this film, we used IL gating to modulate the resistive switching behavior, which shows a change between high-resistance state and low-resistance state during the phase transition and can be used in resistive random access memory devices.