Ternary Ni-Co-F Nanocrystal-Based Supercapacitors.
Chemistry
; 23(28): 6896-6904, 2017 May 17.
Article
em En
| MEDLINE
| ID: mdl-28295730
ABSTRACT
Ternary nickel cobalt fluoride (Ni-Co-F) nanocrystals are constructed solvothermally for use as the positive electrode materials in supercapacitors. The optimal Ni-Co-F (Ni/Co=21) shows slight chemical shifts in X-ray diffraction (XRD) data and X-ray photoelectron spectra (XPS) compared with bare Ni-F and Co-F. The Ni-Co-F (Ni/Co=21) exhibits typical square nanocrystal morphology together with a mesoporous surface structure, as observed through TEM observations and nitrogen sorption measurements. Owing to the stronger synergistic effect of Ni and Co redox species originated from the richer Ni and Co surface electroactive sites, Ni-Co-F (Ni/Co=21) shows superior performances of specific capacitance, rate capability, and charge-transfer kinetics (564â
F g-1 at 1â
Ag-1 , 418â
F g-1 at 16â
Ag-1 , 449â
Ω) compared with all the other Ni-Co-F candidates. Moreover, the activated carbon (AC)//Ni-Co-F (Ni/Co=21) asymmetric capacitor designed based on charge balance delivers superior energy and power densities (18.4â
Wh kg-1 , 6.64â
kW kg-1 ) together with longer cycle life (77 % retention after 10 000â
cycles at 4â
A g-1 ).
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Bases de dados:
MEDLINE
Idioma:
En
Revista:
Chemistry
Assunto da revista:
QUIMICA
Ano de publicação:
2017
Tipo de documento:
Article