摘要
N-doped carbon hollow microspheres have been synthesized by a facile interfacial sol-gel coating process using resorcinol/formaldehyde as the carbon precursor and ethylenediamine (EDA) as both the base catalyst and nitrogen precursor. They possessed uniform size of ~ 120 nm in diameter with porous shells as thin as ~ 10 nm. The BET specific surface area and pore volume were measured to be 267 m2 g−1 and 1.2 cm3 g−1, respectively. The nitrogen doping of 8.23 wt% in carbon matrix could be achieved without sacrificing the hollow spherical morphology. Density functional theory (DFT) calculation results clearly reveal that N-doping could significantly change the interaction sites and enhance the adsorption of PF6- ions towards carbon framework. Quasi-solid-state full sodium-ion capacitors employing the nanoporous disordered carbon nanoparticles and N-doped carbon hollow microspheres as the battery-type negative and supercapacitor-type positive electrodes with a Na+-conducting gel polymer electrolyte were demonstrated. The devices exhibit a comprehensive and superior electrochemical performance in terms of ultrahigh operating voltage of 4.4 V, high energy density of 157 W h kg−1 at 620 W kg−1, and prolonged cycling stability over 1000 cycles with ~ 70% of capacitance retention. Such outstanding performances suggest that the quasi-solid-state full sodium-ion capacitors could be potential safe and flexible electrochemical energy storage devices in the near future.
源语言 | 英语 |
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页(从-至) | 674-680 |
页数 | 7 |
期刊 | Nano Energy |
卷 | 41 |
DOI | |
出版状态 | 已出版 - 11月 2017 |