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Synergistically Active NiCo 2 S 4 Nanoparticles Coupled with Holey Defect Graphene Hydrogel for High‐Performance Solid‐State Supercapacitors
Author(s) -
Tiruneh Sintayehu Nibret,
Kang Bong Kyun,
Kwag Sung Hoon,
Lee YoungHun,
Kim MinSeob,
Yoon Dae Ho
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201705445
Subject(s) - supercapacitor , materials science , capacitance , graphene , cobalt sulfide , nickel sulfide , nanoparticle , hydrothermal circulation , electrode , nanotechnology , sulfide , cobalt , nickel , chemical engineering , electrochemistry , chemistry , metallurgy , engineering
Nickel cobalt sulfide nanoparticles embedded in holey defect graphene hydrogel (HGH) that exhibit highly porous structures and uniform nickel cobalt sulfide nanoparticle sizes are successfully prepared by a facile solvothermal–hydrothermal method. As an electrode material for supercapacitors, the as‐prepared NiCo 2 S 4 @HGH shows ultra‐high specific capacitances of 1000 F g −1 and 800 F g −1 at 0.5 and 6 A g −1 , respectively, owing to the outstanding electrical conductivity of HGH and high specific capacitance of NiCo 2 S 4 . After 2100 charge/discharge cycles at a current density of 6 A g −1 , 96.6 % of the specific capacitance was retained, signifying the superb durability of NiCo 2 S 4 @HGH. Moreover, remarkable specific capacitance (312.6 F g −1 ) and capacity retention (87 % after 5000 cycles) at 6 A g −1 were displayed by the symmetric solid‐state supercapacitor fabricated by using NiCo 2 S 4 @HGH electrodes. These auspicious supercapacitor performances demonstrate that the as‐developed solvothermal–hydrothermal approach can be widely used to prepare graphene‐coupled binary metal sulfides for high‐performance supercapacitor applications.