Citrus-Peel-Derived, Nanoporous Carbon Nanosheets Containing Redox-Active Heteroatoms for Sodium-Ion Storage

Abstract

Advanced design of nanostructured functional carbon materials for use in sustainable energy storage systems suffers from complex fabrication procedures and the use of special methods and/or expensive precursors, limiting their practical applications. In this study, nanoporous carbon nanosheets (NP-CNSs) containing numerous redox-active heteroatoms (C/O and C/N ratios of 5.5 and 34.3, respectively) were fabricated from citrus peels by simply heating the peels in the presence of potassium ions. The NP-CNSs had a 2D-like morphology with a high aspect ratio of >100, high specific surface area of 1167 m(2) g(-1), and a large amount of nanopores between 1 and 5 nm. The NP-CNSs also had an electrical conductivity of 2.6 × 10(1) s cm(-1), which is approximately 50 times higher than that of reduced graphene oxide. These unique material properties resulted in superior electrochemical performance with a high specific capacity of 140 mAh g(-1) in the cathodic potential range. In addition, symmetric full-cell devices based on the NP-CNSs showed excellent cyclic performance over 100,000 repetitive cycles.

3D interconnected macrostructure based on nano-scale pyroprotein units for energy storage

“…These redox-active nitrogen atoms may lead to an increase in capacity and contribute to an enhancement of electrical conductivity via N-type doping effects. 17,18,35 The 3D-IPMs prepared at a HTT of 700 °C exhibit the highest electrical conductivities of all the samples (~2.8 S cm -1 ). That this value is slightly higher than 2.5 S cm -1 supports the effect of nitrogen dopants on electrical properties [ Table 1].…”

“…Topological defect sites typical of hexagonal carbon layers such as mono-and di-vacancies, Stone-Wales defects, adatoms, and edge defects, as well as redox-active heteroatoms such as five-or six-membered nitrogen atoms can be redox hosts for the one phase reaction in the anodic potential region. [14][15][16][17][18][36][37][38] As shown in Hence, a high reversible capacity of ~680 mA h g -1 is achieved at a current density of 500 mA g -1 [ Fig. 4(a)].…”

“…[1][2][3][4][5][6][7][8][9][10][11] This bulk carbon architecture can exhibit nanometer-scale properties such as expanded surface area, which allow for nanoelectronic and nanoionic interactions within the materials' internal spaces and facilitate rapid charge storage via a pseudocapacitive mechanism. 7,12,13 Surface-driven redox reactions occur predominantly on defective carbon structures such as intrinsic topological and edge defects, as well as extrinsic defects, [14][15][16][17][18] However, sp 3 carbon structures have poor electrical conductivities, which result in unfavorable kinetic properties. In contrast, aromatic hexagonal carbon structures need additional energy to store charges on their surface [14][15][16] .…”

Cost‐efficient magnetic nanoporous carbon derived from citrus peel for the selective adsorption of seven insecticides

“…A large amount of citrus peel waste is generally dumped into landfill or disposed of in the ocean. Some compounds such as sugars and phenols emitted from the waste could lead to soil and water pollution . So the citrus waste recycling is of much environmental value.…”

Macroporous Catalytic Carbon Nanotemplates for Sodium Metal Anodes

“…[46] respectively, which are ≈1000 times higher than that of bare Al foil. [47,48] The C/O ratios of MC-CNT-800 and MC-CNT-2400 are 28.8 and 114.0, respectively, and suggest that the quantities of oxygen present are insignificant. A sharp sp 2 CC bonding peak centered at 284.4 eV is observed in the C 1s spectrum of MC-CNT-2400 alongside minor sp 3 CC, CO, and OCO bonding peaks centered at 285.0, 286.4, and 290.2 eV, respectively.…”