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Study of the structure-properties relations of carbon spheres affecting electrochemical performances of EDLCs

Title
Study of the structure-properties relations of carbon spheres affecting electrochemical performances of EDLCs
Author
방진호
Keywords
Carbon sphere; Electrical double layer capacitors (EDLCs); Surface area effect; Size effect; N-doping effect
Issue Date
2019-05
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
Citation
ELECTROCHIMICA ACTA, v. 304, Page. 210-220
Abstract
For high performance of electrical double layer capacitors (EDLCs), a high specific surface area (SSA) and N-doping level, and small particle size of carbonaceous materials, have been believed to be crucial factors. However, there have been few reports on simultaneous study of the structure-properties relations of carbons and the electrochemical performances of EDLCs. Herein, we report the relationship between the structural properties of carbons, such as the SSA, N-doping, and particle size, and the electrochemical properties of EDLCs by using a series of well-defined carbons. Monodisperse and sizetunable resorcinol-formaldehyde carbon (RFC) spheres were synthesized and activated by hot CO2 treatment to increase the SSA up to 3958 m(2)/g (RFC_C390 sample). When the specific capacitances of the RFC spheres were plotted in terms of their SSAs, an almost perfect correlation (R-2 = 0.99) was observed, which confirmed the linear relationship between the specific capacitance and the SSA. In addition, N-doped melanin C (MC) spheres were synthesized and subsequently activated for N-doping effect. Activated MC (MC_C130), which exhibited similar SSA (2618 m(2)/g) and size (301 nm) but a different N-doping level (3.1%) compared with those (2793 m(2)/g, 312 nm, and 1.3%, respectively) of the activated RFC spheres (RFC_C120), displayed higher specific capacitance (288 F/g), capacitance retention (64%), and long term stability over 5000 cycles (93%) compared with those (260 F/g, 58%, and 90%, respectively) of the RFC counterparts. To observe the particle size effect, different sizes (98, 280, and 579 nm) of RFC spheres with similar SSAs (3981, 3958, and 3898 m(2)/g, respectively) and pore size distributions were prepared, such that the smallest RFC revealed the best EDLC performance in terms of specific capacitance (360 F/g), capacitance retention (70%), and long term stability over 5000 cycles (98%), all of which could be compared with the values reported in the literature. Furthermore, all of the Carbon samples were analyzed by using electrochemical impedance spectroscopy for confirming the structure-properties relations of carbon spheres with the electrochemical performances of EDLCs. (C) 2019 Elsevier Ltd. All rights reserved.
URI
https://www.sciencedirect.com/science/article/pii/S0013468619303913?via%3Dihubhttp://repository.hanyang.ac.kr/handle/20.500.11754/111891
ISSN
0013-4686; 1873-3859
DOI
10.1016/j.electacta.2019.02.121
Appears in Collections:
GRADUATE SCHOOL[S](대학원) > BIONANOTECHNOLOGY(바이오나노학과) > Articles
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