Ultrahigh energy storage capacity in multilayer-structured cellulose-based dielectric capacitors caused by interfacial polarization-coupled Schottky barrier height

Abstract

The interfacial polarization-couples Schottky barrier height between BT particles and the C8P2 matrix strongly enhanced the energy storage capacity of this cellulose-based flexible capacitors.

Utilizing the synergistic effect between the Schottky barrier and field redistribution to achieve high-density, low-consumption, cellulose-based flexible dielectric films for next-generation green energy storage capacitors

“…17,26,27,35,48–62 According to the summary in the figure, the cellulose-based composites own better tensile strength but inferior elongation at break than the PVDF-based ones, which is because of the strong hydrogen bond in the cellulose molecular chain network. 19,21,63 Here, the ZSZ shows a tensile strength of 139.05 MPa with elongation at break of 39.47%, and the SZS has a lower tensile strength of 133.96 MPa, but a higher elongation at break of 41.40%. The Young modulus of all the samples was calculated and is shown in Fig.…”

“…A broad peak, which is a result of the combination of the (110) plane of PVDF and cellulose, is detected around 21° in all the films. 21 No peak position shifts in either the powders or the matrix is observed, indicating that the powders' lattice parameter and the matrix's hydroxyl groups remain unchanged before and after compositing. Fig.…”

“…Such a hydrogen network guarantees the successful preparation of a multilayered structure of our films, as we explained in previous work. 21…”

“…Such hydrogen bonds are highly ordered in local regions and thus form polarized dipoles. 19–21 (2) The high insulating behavior comes from their strong adiabaticity, which blocks the conduction heat transfer under a high voltage. 22 However, the polarization of a pristine cellulose film is relatively low, limiting the applications of cellulose-based dielectric materials; therefore, in most cases, ceramic powders with a higher polarization are embedded.…”

“…By the combination of hydrogen bond replacement strategy and the modified tape-casting technique, the sandwich-structured C8P2-BT film was successfully fabricated, with a super-high ESD of 27.2 J cm −3 achieved, which is the highest ESD of cellulose-based films as far as the author knows. 21 However, its energy storage efficiency ( η ) is only about 50%, which is hard to be called an utterly environment-friendly energy storage capacitor. This is attributed to the unreasonable electric field distribution in the multilayers, for which many electrons were thus trapped in the C8P2 matrix, leading to low η .…”