A high-energy-density supercapacitor with graphene–CMK-5 as the electrode and ionic liquid as the electrolyte

Abstract

A graphene-based supercapacitor electrode suitable for ionic liquid electrolytes was designed and prepared based on the electrostatic interactions between negatively charged graphene oxides (GO) and positively charged mesoporous carbon CMK-5 platelets. Thermal annealing of the GO-CMK-5 composite under an inert atmosphere yielded a hierarchical carbon nanostructure with CMK-5 platelets uniformly intercalated between the GO sheets. The electrochemical results demonstrated that the CMK-5 platelets with straight and short mesochannels served as a highway for the fast transport of electrolyte ions, while the separated graphene sheets with more exposed electrochemical surface area favored the formation of electrical double layer capacitance. The RGO-CMK-5 electrode exhibited a specific capacitance of 144.4 F g À1 in 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid electrolyte, which can be charged/discharged at an operating voltage of 3.5 V. As a result, an energy density of 60.7 W h kg À1 and a power density as high as 10 kW kg À1 were achieved, which outperforms most of the present graphene-based supercapacitors. Moreover, the superior rate performance together with the excellent cycle performance makes the RGO-CMK-5 composite a promising candidate for next generation supercapacitor electrodes.

Easy approach to synthesize N/P/K co-doped porous carbon microfibers from cane molasses as a high performance supercapacitor electrode material

“…The surface oxygen content gradually decreased with carbonization temperature increasing from 773.15 to 1173.15 K due to deoxygenation phenomena and further aromatization of the graphitic framework. 29 This has also been corroborated by Raman spectroscopy that the portion of graphitic structure is higher for CMFs carbonized at higher temperatures. The XPS data of C 1s is useful to evaluate the degree of graphitization of carbon materials.…”

“…The G-peak is attributed to the bond stretching of all pairs of sp 2 atoms in ring and chain structures 34 and also well-correlated to the (002) basal reection in the XRD pattern. The integrated intensity ratio of D-peak to G-peak (I D / I G ) provides a useful index to assess the degree of graphitization 29 The coexistence of D-peak and G-peak suggests that CMFs materials are partially graphitic, which is benecial to achieve excellent electrochemical performance.…”

“…Similar observation was reported by Lei and colleagues. 29 To study the contribution of anion species of ILs on the capacitive behavior, the capacitive energy storage of CMF-1073.15 supercapacitor in EMIBF 4 /ACN and EMIDCA/ACN electrolytes was compared. The solvated ion size was estimated by molecular dynamics simulation using HyperChem 8.0.10 soware following Lin et al study.…”

Hierarchically porous carbon by activation of shiitake mushroom for capacitive energy storage

“…Carbon materials with different dimensions, like carbon onions, one-dimensional CNTs, two-dimensional graphene and three-dimensional (3D) carbon-derived carbides, have been extensively explored as supercapacitor electrode because of their good electronic conductivities, facilely controlled pore structures and tailorable surface chemistries [4][5][6][7][8][9]. Among these carbon materials, activated carbons (ACs)…”

Ionic Liquid for High Voltage Supercapacitor

“…2, and E and C are energy density and specific capacitance of SCs, respectively [34]. Figure 4 shows the energy density deference of typical electrolytes of SCs such as KOH aqueous solution, battery electrolyte, and ILs [35]. The hierarchical carbon nanostructure with mesoporous carbon CMK-5 intercalated between reduced graphene oxide (RGO) sheets was proposed as electrode in this research.…”