Silver nanoparticles as a conductive bridge for high‐performance flexible all‐solid‐state asymmetric supercapacitor

Abstract

With the rapid development of portable electronic devices, it is strongly urgent to explore the flexible and sustainable supercapacitor with lightweight, large power/energy density, good cycle stability, outstanding coulombic efficiency, and excellent operational safety. Herein, a novel and flexible all-solid-state asymmetric supercapacitor is assembled from silver (Ag) or/and cobalt acid nickel (NiCo2O4) nanoparticles coated with hollow carbon micro-skeleton (HCMS-Ag and [email protected]2O4-Ag). The [email protected]2O4-Ag electrode is subsequently prepared by a facile hard template combined with hydrothermal method. The morphology analysis shows that plenty of NiCo2O4 nanoflowers composed of a tremendous number of nanoneedles are uniformly grown on the three-dimensional hollow carbon micro-skeleton. This unique and novel structure endows the prepared electrode with a high specific capacitance of 527.4 F g−1 at a current density of 0.5 A g−1 and outstanding rate capability of 75%. The assembled pliable asymmetric supercapacitor possesses a maximum energy density of 42.67 Wh kg−1, long cycle life (97.4% capacitance retention), and excellent flexibility. Therefore, this work opens new horizon to develop the next-generation carbon composites for flexible all-solid-state asymmetric supercapacitor with high levels of electrochemical properties.