Harmonized edge/graphitic‐nitrogen doped carbon nanopolyhedron@nanosheet composite via salt‐confined strategy for advanced K‐ion hybrid capacitors

Abstract

Abstract Nitrogen doping has readily emerged as an efficient solution to boost potassium‐ion storage of carbonaceous materials. Nevertheless, the capacity and lifespan enhancement of derived electrodes is still plagued by the incompetent in coordinating the dopant configurations. In the realm of emerging potassium‐ion hybrid capacitor (PIHC) device, dictating nitrogen doping to enhance pseudocapacitive behavior and improve K+ diffusion kinetics of carbonaceous anodes is scarcely demonstrated. Herein, we report the design of hierarchical N‐doped carbon nanopolyhedron@nanosheet composite via a salt‐confined synthetic strategy with tunable doping configurations toward advanced PIHC anode. A harmonized edge‐ to graphitic‐nitrogen ratio in such dual‐carbon materials enables outstanding rate capability (130 mAh g−1 at 10.0 A g−1) and cyclic performance (with a capacity retention of 80% after 2000 cycles at 5.0 A g−1) in half‐cell tests. As expected, the thus‐assembled PIHC full device with a working voltage of 4.2 V presents a high energy/power density (146 Wh kg−1/8000 W kg−1) and favorable cyclicability. This work is anticipated to offer an innovative insight into the coordination of nitrogen doping configurations in heteroatom‐doped carbon anode targeting high‐performance PIHC applications.

Keywords

• carbon nanopolyhedron@nanosheet composite
• edge‐nitrogen
• graphitic‐nitrogen
• potassium‐ion hybrid capacitor
• salt‐confined synthesis