Hierarchically aminated graphene honeycombs for electrochemical capacitive energy storage

Abstract

Graphene with mediated surface properties and three-dimensional hierarchical architectures show unexpected performance in energy conversion and storage. To achieve advanced graphene electrode supercapacitors, manipulating the graphene building-blocks into hierarchical nanostructured carbon materials with large electrical double layer capacitance and pseudo-capacitance is a key issue. Here, it is shown that the hierarchically aminated graphitic honeycombs (AGHs) with large surface area for electrical double layer capacitance, tunable surface chemistry for pseudo-capacitance, mediated 3D macropores for ion buffering, and low-resistant pathways for ion diffusion are fabricated for electrochemical capacitive energy storage application through a facile high vacuum promoted thermal expansion and subsequent amination process. In the initial stage of amination (200 °C), NH3 reacts with carboxylic acid species to form mainly intermediate amides and amines through nucleophilic substitution. As the temperature increases, the intramolecular dehydration and decarbonylation will take place to generate thermally more stable heterocyclic aromatic moieties such as pyridine, pyrrole, and quaternary type N sites. The AGH exhibits a promising prospect in supercapacitor electrodes with high capacitance (e.g. maximum gravimetric capacitance 207 F g−1 and specific capacitance 0.84 F m−2 at a scan rate of 3 mV s−1) and extraordinary stability (e.g. 97.8% of capacitance retention after 3000 cycles, and 47.8% of capacitance maintaining at a high scan rate of 500 mV s−1 comparing with that at 3 mV s−1). This provides a novel structure platform for catalysis, separation, and drug delivery, which require fast mass transfer through mesopores, reactant reservoirs, and tunable surface chemistry

Impregnation assisted synthesis of 3D nitrogen-doped porous carbon with high capacitance

“…These physicochemical properties of different nitrogen functional groups are believed to determine the mechanism of any related redox reactions. The existing studies reveal that the pseudocapacitive interactions take place with higher reactivity nitrogen, which locate in the edge of carbon lattices, such as pyridinic nitrogen, pyrrolic nitrogen and pyridone nitrogen groups [38][39][40].…”

Efficient amine functionalization of graphene oxide through the Bucherer reaction: an extraordinary metal-free electrocatalyst for the oxygen reduction reaction

“…As shown in Figure 2C [19][20][21][22][23][24][25][26] As can be seen in Figure 2D, the most intense peak assigned to the C-NH 2 , indicating that amino functionalized rGO can be made almost selectively via the suggested method. It is expected that the amino functional groups in the vicinity of doped nitrogen can improve the catalytic property of rGO.…”

Lithiophilic Sites in Doped Graphene Guide Uniform Lithium Nucleation for Dendrite‐Free Lithium Metal Anodes

“…[12] Theas-obtained NG has an itrogen content of 3.14 atom %a sd etermined by X-ray photoelectron spectroscopy (XPS). [12] Theas-obtained NG has an itrogen content of 3.14 atom %a sd etermined by X-ray photoelectron spectroscopy (XPS).…”