Abstract

Development of an efficient electrode material with robust porous architecture, high catalytic activity and excellent electrochemical performance toward both oxygen reduction reaction (ORR) and supercapacitor is extremely important. Herein, a facile route to fabricate nitrogen-doped hierarchical porous carbon (NHPC) materials as a bifunctional electrode material for ORR and supercapacitors is presented. The as-prepared NHPC-0.5 integrate the feature of high-level nitrogen-doping (12.1 at %), large specific surface area (up to 1798.4 m2 g−1) and hierarchical multi-pores of cross-linked micro and mesoporous channels. When used as ORR electrocatalyst, the NHPC-0.5 demonstrated highest selectivity (four-electron transfer process), high activity (half-wave potential 0.883 V vs. RHE, initial potential 1.004 V vs. RHE) and favorable tolerance against methanol. When tested its application in zinc-air batteries, its maximum output power density was 25.1 mW cm−2, and delivers a superior durability of negligible potential loss after 100 cycles. When applied in supercapacitor, the NHPC-0.5 can deliver a high specific capacitance of 283.7 F g−1 at current density of 1 A g−1 in 1 M H2SO4 electrolyte, and outstanding cyclic stability (105.8% capacitance retention after 40,000 cycles). Moreover, a symmetric supercapacitor (NHPC-0.5//NHPC-0.5) can release an energy density of 11.3 W h kg−1 at the power density of 502 W kg−1. The encouraging results of this work may provide a new perspective to construct N-doped hierarchical porous carbon materials in energy storage devices with excellent electrochemical performance.

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