Tuning Nitrogen Species in Two‐Dimensional Carbon through Pore Structure Change for High Supercapacitor Performance

Abstract

Carbonaceous materials have long been a key component of supercapacitor energy storage systems, and exploring nitrogen atom doping and its role is currently the focus of carbon-based electrode development. However, achieving a high proportion of pyridinic N (active N) in N-doped carbon is still a big challenge. Here, by introducing a triblock copolymer F127 into the phenolic resin, the pore structure of the two-dimensional carbon material is successfully adjusted, thereby increasing the probability of generation of active nitrogen. We found that this two-dimensional porous structure is beneficial to the formation of pyridinic N. Through the change of pore structure, the ratio of pyridinic N to the total N was further increased by 13.9 %.Therefore, it provides a large specific capacitance (220 F g À 1 ), excellent cycle stability (93.6 %) and high rate performance (71.2 %) in the alkaline KOH electrolyte. To further increase the energy density, we constructed an symmetrical supercapacitor device using an ionic liquid electrolyte (equal amount of 1ethyl-3-methylimidazolium tetrafluoroborate and acetonitrile). As a result, since the electrolyte has a voltage window of up to 3 V, the energy density is as high as 37.5 Wh kg À 1 . This superior performance indicates that adjusting the ratio of pyridinic N provides a promising method for preparing excellent N-doped carbon materials for energy storage systems.

Preparation of N/O co-doped porous carbon by a one-step activation method for supercapacitor electrode materials

“…Three types of oxygenated groups were found: CO (531.2 eV), C–OH/C–O–C (532.15 eV), and OC–O (532.97 eV). 32 The relative contribution of CO is the highest. CO and other oxygen-containing functional groups play active roles in the Faraday reactions during charge/discharge processes.…”

“…Three types of oxygenated groups were found: C]O (531.2 eV), C-OH/C-O-C (532.15 eV), and O]C-O (532.97 eV). 32 The relative contribution of C]O is the a Calculated using a multi-point BET method. b N, O represent their atomic content.…”

Tailoring the phase composition of carbon-coated nickel sulfides to achieve a high specific capacitance

“…The increased specific surface area of NiS 2 /NiS@C1 with an enhanced porous structure can shorten the ion diffusion pathway and enhance the specific capacitance of the electrode. 39…”

“…The increased specific surface area of NiS 2 /NiS@C1 with an enhanced porous structure can shorten the ion diffusion pathway and enhance the specific capacitance of the electrode. 39 Fig. 6a presents the FTIR spectra of nanohybrids of NiS@C0, NiS 2 /NiS@C1 and NiS 2 /NiS@C2.…”

Insights on advanced g‐C3N4 in energy storage: Applications, challenges, and future

“…[263][264][265] g-C 3 N 4 , as a special nitrogen-doped carbon material, has rich nitrogen content and can enhance surface polarity and improve surface wettability. 266,267 It is easy to graft with other materials due to its highly crystalline layered structure, transfer of charges along the horizontal direction, and large surface area. It can offer more active sites, improve the electron acceptor/donor properties, and provide additional pseudocapacitance.…”