Constructing a Carbon-Encapsulated Carbon Composite Material with Hierarchically Porous Architectures for Efficient Capacitive Storage in Organic Supercapacitors

Abstract

Hierarchical porous activated carbon (HPAC) materials with fascinating porous features are favored for their function as active materials for supercapacitors. However, achieving high mass-loading of the HPAC electrodes remains challenging. Inspired by the concepts of carbon/carbon (C/C) composites and hydrogels, a novel hydrogel-derived HPAC (H-HPAC) encapsulated H-HPAC (H@H) composite material was successfully synthesized in this study. In comparison with the original H-HPAC, it is noticed that the specific surface area and pore parameters of the resulting H@H are observably decreased, while the proportions of nitrogen species are dramatically enhanced. The free-standing and flexible H@H electrodes with a mass-loading of 7.5 mg/cm2 are further prepared for electrochemical measurements. The experiments revealed remarkable reversible capacitance (118.6 F/g at 1 mA/cm2), rate capability (73.9 F/g at 10 mA/cm2), and cycling stability (76.6% of retention after 30,000 cycles at 5 mA) are delivered by the coin-type symmetric cells. The cycling stability is even better than that of the H-HPAC electrode. Consequently, the findings of the present study suggest that the nature of the HPAC surface is a significant factor affecting the corresponding capacitive performances.

In Situ Construction of Nitrogen-Doped and Zinc-Confined Microporous Carbon Enabling Efficient Na+-Storage Abilities

“…As revealed, only two broad peaks representing the (002) and (100) crystallographic planes of carbon (JCPDS No. : 41-1487) were detected [38]. When analyzing the (002) peak using the Gaussian-Lorentzian method from 2θ of 16° to 32°, it can be seen that the 2θ value was fitted well to be 24.18° (see Figure S3), corresponding to the d-spacing of 0.37 nm.…”

“…To figure out this idea, the Raman spectrum analyzed by the Gaussian-Lorentzian method was further deconvoluted into four peaks, which were labeled as peaks (1) to (4) in Figure 4. Among them, peaks (1) and ( 3) are associated with sp 3 -type carbon, while the others are related to sp 2 -type carbon [38,41]. The integrated area ratio of sp 3 to sp 2 (A sp 3 /A sp 2 ) has been demonstrated to provide insightful information on the nature of carbonaceous materials, e.g., a low A sp 3 /A sp 2 ratio gives that a larger amount of carbon exists as sp 2 -type [42].…”

Carbon-Based Nanomaterials 3.0

“…Therefore, developing an HPAC that increases the mass loading of the resulting electrode is highly desirable. In this regard, Amirtha et al [ 11 ] prepared a novel hydrogel-derived encapsulated H-HPAC (H@H) composite material, with reduced specific surface area and pore parameters but increased proportions of nitrogen species. The free-standing and flexible H@H electrodes showed remarkable reversible capacitance, rate capability, and cycling stability and are also promising electrode materials for other energy storage fields such as metal–ion capacitors.…”