Highly Crosslinked Conductive Polymer Nanofibrous Films for High‐Rate Solid‐State Supercapacitors and Electromagnetic Interference Shielding

With their low cost and unique physicochemical properties, conductive polymer‐ based film electrodes drew much attention in flexible electronic devices. However, their poor intrinsic conductivities limit their applications in high‐rate supercapacitors or high electromagnetic interference (EMI) shielding performance. It is meaningful to deal with the issue through the rational design of the film nanostructure. Herein, using specially treated PEDOT:PSS coated polyacrylonitrile (PAN) nanofibrous films (PPNFs) as a current collector, polyaniline (PANI) or polypyrrole (PPy) based highly crosslinked conductive nanofibrous films (HCC‐NFs), named as PANI@PPNF and PPy@PPNF, are fabricated. The PANI@PPNF electrodes exhibit a specific capacitance of 156 mF cm–2 at a current density of 1 mA cm–2. Meanwhile, 41% capacity (64 mF cm–2) remained even at 20 mA cm–2. The remarkable rate performance of PANI@PPNFs demonstrates the HCC‐NF structure brings a high‐rate character for pseudocapacitive material. Furthermore, the solid‐state supercapacitor shows long‐term cycle stability at a high scan rate of 1 V s–1 for 5 000 cycles and over 75% of the specific capacitance is retained, suggesting excellent cycle stability of PANI@PPNF. Besides, PANI or PPy based HCC‐NFs show high performance in EMI shielding. This conductive polymer‐based HCC‐NF structure offers a promising platform for designing multi‐functional flexible electronic devices. Highly crosslinked nanofibrous polyaniline (PANI) or polypyrrole‐based films are synthesized. The PANI‐based film is effective for preparing high rate supercapacitors as the highly crosslinked structure offers an effective network for electrons to quickly transfer, and the porous structure allows electrolytic ions to move fast to the surface. These films also exhibit excellent electromagnetic interference (EMI) shielding performance (EMI SE of 40 dB).