Flexible Integrated Self-Charging Capacitor System with High Power Density Enabled by Mechanically Nanostructured Ferroelectric

We report a flexible self-charging capacitor system that integrates a triboelectric nanogenerator (TENG) with a flexible Pb(Zr_xTi₁-_x)O₃ (PZT) ferroelectric ceramic capacitor by aerosol-deposition (AD). The flexible PZT capacitor demonstrated high energy storage capabilities, achieving a recoverable energy density of 35.8 J cm⁻³ under an applied electric field of 2000 kV cm⁻¹, as determined from the measured polarization-electric field (P-E) hysteresis curve. To enhance triboelectric performance, a micro-imprinting process is applied to the Al surface in the TENG, improving the contact surface area and output performance. Using biomechanical tapping as an input, the TENG produced a rectified open-circuit voltage of 350 V, corresponding to an electric field of 1000 kV cm⁻¹ across the PZT capacitor. The flexible self-charging PZT capacitor exhibited a recoverable energy density of 5.9 J cm⁻³ and a discharge power density of 16.0 MW cm⁻³. This improved power density is achieved through the combination of a simple micro-patterning technique on the TENG and the annealing of the AD PZT film, which induced a slim ferroelectric P-E hysteresis behavior. Our results suggest that this flexible self-charging system holds significant promise for powering next-generation flexible smart devices and high-power electronics, offering a scalable and efficient approach to energy harvesting and storage.