Biowaste-Derived Porous Carbon with Tuned Microstructure for High-Energy Quasi-Solid-State Supercapacitors

Abstract

Solid-state supercapacitors hold great promise in future portable electronics. However, designing ideal electrode materials from eco-friendly strategies to further improve the energy density and operational potential window is crucial for commercialization of the devices. Herein, a clean and economic strategy to fabricate a 3D self-doped honeycomb-like carbonaceous material from biowaste is reported. The optimal carbon sample (HSC-0.50) features high surface area and relatively high packing density, resulting in outstanding performance. A thorough electrochemical investigation is also involved in this work, which shows that the gravimetric and volumetric capacitances of the prepared HSC-0.50 sample are obtained as high as 281.4 F g–1 and 247.6 F cm–3 at 0.5 A g–1 coupled with a superior rate capability (83.2% retention at 100 A g–1). In addition, the HSC-0.50 sample can deliver high volumetric and areal capacitances of 204.7 F cm–3 and 4.7 F cm–2 using a 6.0 M KOH electrolyte even under a high loading of 20 mg cm–2. Remarkably, a 1.8 V symmetric quasi-solid-state supercapacitor is successfully constructed by using the HSC-0.50 electrode in a seldom used gel electrolyte (carboxymethylcellulose sodium/sodium sulfate, CMC-Na/Na2SO4). A superhigh energy output of 23.4 Wh kg–1 over that of an alkaline device (7.6 Wh kg–1) with excellent cyclability over 10 000 cycles can be achieved in the as-designed cell. This research highlights that the utilization of high-voltage CMC-Na/Na2SO4 gel as a low-cost and eco-environmental electrolyte, coupled with sustainable and high-capacitance biowaste-derived carbon, may open up a new avenue for the establishment of promising energy storage systems.

Carbon Quantum Dot Incorporated Nickel Pyrophosphate as Alternate Cathode for Supercapacitors

“…Nevertheless, it exhibits poor cycling stability and limited rate performance, which may be ascribed to the lower electrical conductance and irreversible phase transformation. It was reported that the addition of carbonaceous materials could enhance the performance of the faradic type electrode materials . For example, Piaopiao Sun et al.…”

Hydrothermal Carbonization of Renewable Natural Plants as Superior Metal-Free Catalysts for Aerobic Oxidative Coupling of Amines to Imines

“…After hydrothermal treatment, the population of oxygen became slightly reduced, which is also confirmed by elemental analysis results (Table S4). Moreover, the XPS spectra of high-resolution O 1s (Figures B,C and S4B,C) show that the hydrochar surface is enriched with different contents of oxygen functional groups such as −CO (531.9 eV) and −COOH (533.6 eV) . FT-IR measurements show that the hydrochars have an aliphatic methylene group (2913 cm –1 ) and a hydroxyl group (3400 cm –1 ) similar to raw materials (Figures D and S4D).…”

“…Moreover, the XPS spectra of highresolution O 1s (Figures 4B,C and S4B,C) show that the hydrochar surface is enriched with different contents of oxygen functional groups such as −CO (531.9 eV) and −COOH (533.6 eV). 32 FT-IR measurements show that the hydrochars have an aliphatic methylene group (2913 cm −1 ) and a hydroxyl group (3400 cm −1 ) similar to raw materials (Figures 4D and S4D). 33 FT-IR-detectable chemical changes occurred as raw materials were hydrothermally carbonized.…”

Nano-Structured Carbon: Its Synthesis from Renewable Agricultural Sources and Important Applications

“…Bio-inspired methods are also used with natural biological materials for the systematic production of nanostructured carbon materials [ 52 ]. According to the application of the nanocarbon, their structures such as pore size, surface area, chemical composition, and functional groups can be tuned by varying the synthesis conditions [ 53 , 54 , 55 ]. Reduction of the graphene to graphene oxide nanosheets was prepared with Hammer’s method to receive high purity graphite, and reported being cost effective, eco-friendly, and efficient [ 56 ].…”