Hybrid pseudocapacitor materials from polyaniline@multi-walled carbon nanotube with ultrafine nanofiber-assembled network shell

Porous carbon-based hybrids consisting of nanoscale building units are highlighted as supercapacitive materials for outstanding rate capability and cyclability. Herein reported are new hierarchically porous core-shell hybrids of polyaniline@multi-walled carbon nanotube (PANI@MWCNT) with ultrafine nanofiber-assembled network shell for supercapacitors via a facile reverse microemulsion polymerization route. Among various as-prepared samples, PANI@MWCNT2 hybrids (72 wt.% PANI loading) show the maximum specific capacitance of 663 F g−1 at 0.5 A g−1 with good capacitance retention of about 87% at 2 A g−1 in contrast to pure PANI (526 F g−1 with 76% retention) and other hybrids (613 and 538 F g−1 for the hybrids with 84 wt.% and 48% wt.% PANI, respectively). Moreover, 82% of initial capacitance still remains over 1000 cycles at 5 A g−1 for PANI@MWCNT2. The data clearly reveal a dramatic improvement of the hybrids in performance containing capacitance and rate capability meanwhile lifetime, thanks to unique structure features with highly surface-porous PANI nanofiber networks intimately wrapped around conductive MWCNTs helping to greatly promote faradic redox process and cycling behavior.