No abstract

The molten salt activation containing different oxysalts are proposed to activate the ordered mesoporous carbons loading on graphene layers (OMC/G). The effects of different oxysalts activations on the structures of OMC/G are thoroughly investigated by scan electron microscopy (SEM), small angle X‐ray scattering (SAXS), Raman spectroscopy and nitrogen adsorption‐desorption at 77 K. The structures of these carboneous materials are related with the oxidizing nature of these oxysalts. By using weak oxysalt of K2CO3, the original structure of OMC/G is almost kept together with the appearance of a lot of micropores and mesopores. The electrochemical performances of OMC/G after different oxysalts activation are also studied for supercapacitor applications. OMC/G after weak oxysalt of K2CO3 based electrode results in the highest specific capacitance up to 332.5 F g−1 at a current density of 1.0 A g−1, which is higher than those after both KOH activation (276.8 F g−1) and the other three oxysalts activation. Moreover, OMC/G‐K2CO3 shows an excellent cycling stability with no capacitance loss over 5000 cycles. The molten salt activation would be potentially applied to activate the porous carbons for supercapacitor applications.

Ordered mesoporous carbons (OMC) loading on sulfonated graphene (OMC/SG) have been fabricated by multi-components co-assembly followed by thermal polymerization and carbonization. OMC/SG composites possess the hierarchically ordered hexagonal mesostructure with the lattice unit parameter and porous diameter about 10 nm and 4 nm, respectively. Sulfonated graphene is integrated into the interpenetrated network structures via covalent bonding and hydrogen bonding, as well as is highly dispersed in OMC matrix. OMC/ SG composite shows a specific surface area high up to 1708.78 m 2 g À 1 , and a mesoporous ratio as high as 80 %. Meanwhile, the obtained OMC/SG exhibits a specific capacitance as high as 314.2 F g À 1 at 1.0 A g À 1 , while OMC based electrode is only 196.6 F g À 1 . In addition, the resultant OMC/ SG composites display good rate capability (70 % of the capacitance retained at current density high up to 100 A g À 1 ), and an excellent cycling stability (no capacitance loss over 5000 cycles). In particular, the surface capacitance of OMC/ SG (C s ) increases up to 18.4 μF cm À 2 at 1 A g À 1 . These optimized interconnected porous structures in the OMC/SG composites are favorable to the accessibility, rapid diffusion of aqueous electrolytes, while sulfonated graphene can also facilitate the transport of electrons and provide better interface wettability of electrodes with electrolytes, thereby leading to an excellent energy storage performance.[a] S. . XPS survey spectra of OMC/SG-0.04 and OMC (a), S 2p XPS spectra of OMC/SG-0.04 (b), C 1s XPS spectra of OMC/SG-0.04 (c) and OMC (e), O 1s XPS spectra of OMC/SG-0.04 (d) and OMC (f).