Flexible all-solid-state supercapacitor based on polyhedron C-ZIF-8/PANI composite synthesized by unipolar pulse electrodeposition method

Abstract

In this work, the unipolar pulse electrodeposition (UPED) method is used to electrodeposit the conductive polyaniline (PANI) on the carbonized polyhedron zeolitic imidazole particles (C-ZIF-8). The composite film of C-ZIF-8/PANI coated on the flexible substrate stainless steel wire mesh (SSWM) offers large contact area between the electrode material and the electrolyte, which provides enough active sites for charge storage. The obtained flexible electrode exhibits efficient-specific capacity of 363 F g−1 with 300° stretching angle and excellent long-term cycling stability after 10,000 cycles at 5 mA g−1 in 1 M H2SO4 electrolyte. It is found that the flexible electrode shows obvious improvement in the electrochemical properties when it was bent or stretched. Asymmetrical all-solid-state supercapacitor device is fabricated by using polyvinyl alcohol (PVA) solid gel as electrolyte and separator, which shows general gravimetric capacitance of 147, 156, and 156 F g−1 with energy densities of 8.66, 9.16, and 9.16 W kg−1 at stretching angle of 0°, 120°, and 300°, respectively, and stable power density of 162.5 W kg−1 in the different conditions. It indicates that such a composite C-ZIF-8/PANI/SSWM is a favorable material for portable and flexible energy storage.