As passive components in flexible electronics, the dielectric capacitors for energy storage are facing the challenges of flexibility and capability for integration and miniaturization. In this work, the all-inorganic flexible dielectric film capacitors have been obtained. The flexible capacitors show a desirable recoverable energy density ( Wrec) of 40.6 J/cm3 and a good energy efficiency (η) of 68.9%. Moreover, they have no obvious deterioration on both the Wrec and η after 104 times of mechanical bending cycles or under the bending state with a curvature radius of 4 mm. Besides, the outstanding stability of the capacitors against cycle fatigue over fast 106 charge-discharge cycles is demonstrated. Most importantly, they work properly at a wide temperature range from -120 to 150 °C with Wrec > 15 J/cm3 and η > 70%. These fascinating performances endow the flexible capacitors with huge potential application in the future "microenergy storage" system in flexible electronics.
Keywords: all-inorganic embedded capacitors; energy storage; fatigue stability; flexible; wide temperature range.