LAUSR

Abstract 3D interconnected hierarchical porous N-doped carbon nanotubes (IHPNCs) were fabricated using palygorskite as template and polyaniline gel as carbon source, respectively. The prepared 3D IHPNCs show high specific surface area (517.02 m2 g−1), hierarchical porous structure (micropore (0.39 nm), mesopore (4.0 nm), macropore (≥50 nm)) and N-containing surface functionalities (pyridinic-N, pyrrolic-N, graphitic-N, N-oxides). Notably, the obtained 3D IHPNC electrodes exhibit a high specific capacitance of 389 F g−1 at 1 A g−1, excellent rate capability (290 F g−1 at 50 A g−1, 75% of capacitance retention) and cycling stability with 90% retention after 10000 cycles. Furthermore, the assembled 3D IHPNC symmetric supercapacitor delivers a high energy density of 8.7 Wh·kg−1 at a power density of 195 W kg−1 in 1.0 M Na2SO4 electrolyte, which is expected as a promising electrode candidate for supercapacitors.