Extraordinarily high-rate capability of polyaniline nanorod arrays on graphene nanomesh

We report the high-rate capacitive performance of polyaniline (PANI) coated on graphene nanomesh (GNM). The PANI on GNM sheets shows vertical nanorod arrays that offer large electrochemically active surface area and numerous ion-accessible gaps. Benefiting from the highly pseudocapacitive PANI and ion penetrable GNM, GNM-PANI with 70 wt% PANI exhibits a specific capacitance of 452 F g(-1) at 1.0 A g(-1), which remains at 404 F even at high discharge rate of 50 A g(-1) in 1.0 M H2SO4. More importantly, a symmetric capacitor built with this electrode exhibits a relaxation time constant of 2.61 s, a value comparable to 2-5 s with activated carbon as electrode, and much shorter than 4-6 s of capacitors with chemically converted graphene as electrodes. The performance of GNM-PANI electrode reported herein is far superior to that of most other PANI-based electrodes, demonstrating that GNM is a promising scaffold that can help to realize the full potential of PANI due to its abundant in-plane nanopores. (C) 2015 Elsevier B.V. All rights reserved.