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

• PANI nanorod arrays were successfully coated on graphene nanomesh (GNM).
• GNM with unique in-plane nanopores favors ion transport and electron migration.
• GNM-PANI electrode exhibits both high-capacitance and high-rate capability.

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 g−1 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.

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