Premium
Nitrogen‐Doped Accordion‐Like Soft Carbon Anodes with Exposed Hierarchical Pores for Advanced Potassium‐Ion Hybrid Capacitors
Author(s) -
Zhang Chen,
Liu Xing,
Li Zhen,
Zhang Chenying,
Chen Zhiwen,
Pan Dengyu,
Wu Minghong
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202101470
Subject(s) - materials science , anode , pseudocapacitance , chemical engineering , dielectric spectroscopy , energy storage , nanotechnology , raman spectroscopy , supercapacitor , carbon fibers , capacitance , electrode , electrochemistry , composite material , composite number , power (physics) , chemistry , physics , optics , quantum mechanics , engineering
Soft carbon (SC) is a promising anode material for potassium‐ion hybrid capacitors (PIHCs), but there are limited K + storage sites in common SC due to a skin‐like carbon film covering on the surface. To address this issue, a simple oxidization method to completely remove the skin‐like carbon film is reported and a novel accordion‐like architecture of SC (ASC) is constructed with a hierarchical porous framework composed of micropores, mesopores, and macropores, all of which can be exposed to K + electrolytes for enhanced energy storage. Importantly, this exposed structure facilitates pseudocapacitance modification by electro‐deposition of highly electrochemically active nitrogen‐doped graphene quantum dots (N‐GQDs) to enhance kinetic performance and additional K + storage. After annealing treatment to regulate N‐doping type, the accordion‐like N‐GQD@ASC‐500 exhibits excellent reversible capacity of 360 mAh g −1 as well as superior rate capability and cycle stability. Kinetic, in situ Raman/electrochemical impedance spectroscopy analysis, and density functional theory calculation elucidate the K + storage mechanism. As expected, the PIHC assembled with N‐GQD@ASC‐500 anode and porous carbon cathode delivers an ultrahigh energy/power density (171 Wh kg −1 and 20 000 W kg −1 ) with long cycle life. This work suggests that ASC is a promising anode material for designing of high‐performance PIHCs.