Flexible ultrathin all‐solid‐state supercapacitors

Abstract The flexible ultrathin all‐solid‐state supercapacitors with good electrochemical and mechanical performance were fabricated by the facile methods. The single‐wall carbon nanotubes (SWCNTs)–polyaniline (PANI) film electrodes and poly(vinyl alcohol) (PVA)/H 3 PO 4 electrolyte film were prepared by spray‐printing and spin‐coating strategies, respectively. Thus, the thickness of a supercapacitor is only 8.4 μm. When the mass ratio of SWCNT to PANI is 1:1, the tensile strength and Young’s modulus of the electrode are 10.9 and 655 MPa, respectively. The interior contact resistance of the supercapacitors based on this electrode is only 15–30 Ω. Furthermore, the specific capacitance of this electrode can reach about 355.5 F·g −1 , and the supercapacitor based on this electrode maintains 87.2% of its initial specific capacitance over 5000 charging/discharging cycles. Moreover, the supercapacitor shows an excellent electrochemical stability at different bending states. Therefore, the all‐solid‐state supercapacitors prepared by our strategies would meet the demands of wearable, lightweight, and compact energy storage devices.