In situ form core-shell carbon nanotube-imide COF composite for high performance negative electrode of pseudocapacitor

Abstract

High performance negative electrode material of pseudocapacitor is of paramount importance for the device energy storage capacity. Herein, a novel carbon nanotube-imide COF composite negative electrode material was successfully prepared by in situ growth of imide COF on the wall of nanotubes containing amine groups. FT-IR, XRD, SEM and HR-TEM verify that the core-shell composite was formed. Driven by the π-π interaction between carbon nanotube and imide COF, the composite exhibits high electron conductivity. N2 adsorption-desorption test further displays that the composite still possesses adequate porous structure with a high specific surface area of 386 m2 g−1. The unique core-shell structure enables the carbon nanotube-imide COF composite with high energy storage capacity, a high specific capacitance of 278 F g−1 at 0.5 A g−1 between -1 V to 0 V in the neutral electrolyte, among the best results for the recent reported high performance negative pseudocapacitance organic materials. Interestingly, the composite still gives a high specific capacitance of 72 F g−1 at high current density of 50 A g−1. These interesting energy storage properties should be attributed to the synergetic mechanism between carbon nanotube and COF. Moreover, the asymmetric device assumed with the carbon nanotube-imide COF composite as the negative material and the RuO2 as the positive material, displays high energy density of 25.9 W h kg−1 with a power density of 357.2 W kg−1. The composite negative material design idea would offer reference for other high performance energy storage materials.