In Situ intercalating expandable graphite for mesoporous carbon/graphite nanosheet composites as high-performance supercapacitor electrodes.
Mesoporous-carbon-coated graphite nanosheet (GNS@MC) composites have been synthesized by the intercalation of resol prepolymer into the interlayers of expandable graphite (EG) under vacuum-assisted conditions, followed by the exfoliation of EG through in situ polymerization, the growth of resol under hydrothermal conditions, and carbonization under Ar. The GNS@MC composites exhibit enhanced capacitive performance compared to mesoporous carbon (MC), microwaved EG after thermal treatment (T-EG), and the physical mixture of MC and T-EG (MC+T-EG). In particular, the GNS@MC-35-800 composite carbonized at 800 °C, which has a graphite-nanosheet content of 35 % and a Brunauer-Emmett-Teller surface area (S(BET) ) of 432.3 m(2)  g(-1) , exhibits the highest capacitance of 203 F g(-1) at 1 A g(-1) in 6 M KOH electrolyte. Furthermore, the GNS@MC-35-800 composite exhibits a good cyclic stability with 95 % capacitance retention and a high columbic efficiency of 99 % after 5000 cycles. The energy density of the symmetric supercapacitor GNS@MC-35-800/GNS@MC-35-800 achieved was as high as 11.5 Wh kg(-1) at a high power density of 10 kW kg(-1) . This good performance is attributable to the GNSs in the GNS@MC composite facilitating electron transport owing to its excellent conductivity; moreover, the MC in GNS@MC favors the rapid diffusion of ions by providing low-resistance pathways. The GNS@MC composite may find application in high-performance energy storage and conversion devices.
Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, PR China.
Lei
L
Wang
Guang
G
Mu
Chungui
C
Tian
Li
L
Sun
Wei
W
Zhou
Taixing
T
Tan
Honggang
H
Fu
D002244:Carbon / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D004867:Equipment Design; D005557:Formaldehyde / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008872:Microwaves; D049329:Nanostructures / Q000737:chemistry*; D019800:Phenol / Q000737:chemistry; D016062:Porosity; D013499:Surface Properties
D005557:Formaldehyde; D019800:Phenol; D002244:Carbon; D006108:Graphite