Simple Hydrogen-Bonding Cross-Linking Effect Improves the Energy Storage Density of All-Organic Dielectric Polymer Films

High-energy-density polymer dielectrics are of critical significance for advancing the miniaturization and integration of capacitors. To enhance the dielectric properties and energy storage density of poly(vinylidene fluoride) (PVDF), this study employs hydroxyl-rich ethyl cellulose (EC) incorporated into the PVDF matrix to construct all-organic flexible dielectric films. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) test results show that the hydrogen bonding interaction between EC and PVDF leads to a higher β phase content. The ratio of the peak intensity values of the characteristic peaks belongs to the β phase, and the α phase (I_β/I_α) of the 0.5 wt %EC/PVDF is 1.76, much higher than the I_β/I_α value of PVDF (1.31). The increase in the polar phase content enhances the polarization ability of all-organic films. The dielectric constant of 0.5 wt %EC/PVDF reaches 10.43 at 100 Hz. The hydrogen bonding interaction and physical entanglement between EC and PVDF enhance the breakdown strength of the all-organic films. The breakdown strength of 1 wt %EC/PVDF reaches 462.83 MV/m. The discharge energy density of EC/PVDF all-organic films is effectively improved, and the discharge energy density of 0.5 wt %EC/PVDF reaches 6.02 J/cm³, 1.8 times that of PVDF (3.35 J/cm³). Owing to its improved performance, simple preparation process, and low cost, this technique is well-suited for the mass production of polymer dielectrics.