The journal Carbon is an international multidisciplinary forum for communicating scientific advances in the field of carbon materials, including low-dimensional carbon-based nanostructures. The journal reports new, relevant and significant findings related to the formation, structure, properties, behaviors, and technological applications of carbons, which are a broad class of ordered or disordered solid phases composed primarily of elemental carbon. These materials can be either synthetic or of natural origin, and include, but are not limited to: carbon black; carbon fibers and filaments; carbon nanotubes; diamond and diamond-like carbon; fullerenes; glassy carbon; graphite; graphene; graphene-oxide; porous carbons; pyrolytic carbon; and other sp2 and non-sp2 hybridized carbon systems.
CNTs were directly grown on basalt fi ber fabrics, and these fabrics showed excellent electromagnetic interference shielding. Chang et al. CARBON Volume 167, Pages 31-39, 2020Carbon - Volume 167
Cover Highlight: Direct growth of carbon nanotubes on basalt fiber for the application of electromagnetic interference shielding
This paper reported the preparation of a hierarchical structure consisting of micro-scale basalt fiber fabric and nano-scale carbon nanotubes (CNTs). The developed fabric was employed as reinforcement to develop nanocomposites with multi-layer structures for electromagnetic interference shielding. Different techniques were employed to study the morphologies and properties of the fabric and corresponding nanocomposites. The results showed that by optimizing the experimental conditions, CNTs with controlled content and quality were grown on the surface of basalt fiber. These properties significantly affected the electromagnetic interference shielding performance of corresponding nanocomposites. The novelty of this study lies in the direct growth of nanotubes on basalt fiber by utilizing the in-situ generated mineral nanoparticles on fiber surface as a catalyst, and a spontaneous infusion of uncured polymer into the fabric, which eliminates the problems associated with the dispersion and re-agglomeration of CNTs during the preparation of nanocomposites.
Plasma-synthesized heteroatom-doped carbon anode materials for sodium ion batteries with ultra-high rate capabilities. Kim et al. Vol. 168 pages 448 to 457Carbon - Volume 168
Cover Highlight: Novel synthesis of highly phosphorus-doped carbon as an ultrahigh-rate anode for sodium ion batteries
Carbonaceous materials are the most promising anode materials in electrochemical energy storage systems. However, poor electrochemical performance is a major obstacle to their practical use. Here, P-doped carbon balls (PCBs) are synthesized through a simple novel method, the solution plasma process (SPP), which is different from the conventional synthesis method, and used as an anode material in sodium ion batteries (SIBs). The PCBs synthesized by this approach show a high P content of about 4 at%. Meanwhile, P doping and disordered amorphous structures of PCBs provide abundant active sites and capacitive-dominant Na+ adsorption behavior, while large amounts of meso- and macropores shorten the Na+ diffusion distance, accelerating ion transport. The PCB anode material provides a high initial coulombic efficiency of about 75% and a high reversible capacity of 340 mAh g−1 at a current density of 1 A g−1. Even at an ultrahigh current density of 100 A g−1, an outstanding rate performance of 130 mA g−1 and reversible capacity of 83 mAh g−1 after 40,000 cycles provide excellent cycling stability. This synthesis strategy not only provides a very efficient approach to heteroatom doping but will also be a great impetus for the practical use of SIBs.
Carbon is often the black sheep of elements (coal mines, global warming, dust lungs, …), but carbon is also the queen of elements (DNA, diamond, graphene, …). Therefore, it is clear that carbon is versatile and complex. This huge ‘carbon sandbox’ is now catapulting mankind into a new era. Mendez-Linan et al. Volume 169, November 2020, Pages 32-44.Carbon - Volume 169
Cover Highlight: Aging effect of plasma-treated carbon surfaces: An overlooked phenomenon
Carbon surfaces become significantly activated with plasma treatment enhancing the surface energy, wettability, and bio-conjugation. However, the activated surfaces are influenced by aging effect or reorientation phenomenon, a rarely reported occurrence, that refers to the loss of surface activity with time. Generated plasma-activated surface functional groups suffer from a brief shelf life as they reorient themselves to occupy lower states of energy. This study thoroughly assesses plasma-treated pyrolyzed carbon platforms with O2, N2, and Ar plasma radiations over 3 weeks. Pristine, immediately treated, and aged carbon samples were analyzed by SEM, AFM, WCA, and XPS to observe physical and chemical changes of the surfaces. Moreover, the electrochemical analyses demonstrated radical alterations of the surface characteristics immediately after the treatment; an activation which did not last long regardless of the plasma choice. With time, clear signs of surface inactivation were recorded manifesting in the form of decreased roughness, increased water contact angle, and major alterations of surface chemical composition, capacitance, and resistance. Our observations confirm that the plasma-treated carbon samples return to the pristine surface characteristics within a brief period of time thus demonstrating the loss of surface activity irrespective of the treatment choice.
Polymer electrolyte fuel cells are very promising highly effi cient and zero-emission power sources. Carbon black is used as an ideal support material for catalyst nanoparticles in polymer electrolyte fuel cells. Kumano et al. Volume 169, November 2020, Pages 429-439Carbon - Volume 170
Cover Highlight: Influence of ionomer adsorption on agglomerate structures in high-solid catalyst inks
Sodium-ion batteries (SIBs) have been attracting an ever-growing research interest, mainly ascribed to their cost-effectiveness. However, SIBs have been significantly hindered by lack of a suitable anode. Herein, an exceptional Cu2S-based composite anode is developed via a facile ball-milling method, in which Cu2S particles are wrapped by nitrogen-doped graphene sheets (Cu2S@NG). This Cu2S@NG composite anode enables extremely long cycling life, ultra-stable cyclability with high capacity, and excellent rate capability. The superior performance of the Cu2S@NG composite is owing to its intriguing core-shell structure and the exceptional properties of both the Cu2S and NG. In this study, it is found that the NG shell yields multiple merits in improving the performance of Cu2S: (i) mitigating the loss of active materials, (ii) constituting a stable interface, (iii) providing improved electrical conductivity and good ionic transfer, and (iv) enhancing mechanical integrity. Additionally, the vital effects of different voltage windows and a surface coating via atomic layer deposition on further enhancing performance are clarified. Significantly, the electrochemical mechanism of Cu2S during sodiation/desodiation is unveiled using advanced synchrotron-based in-situ X-ray diffraction and X-ray adsorption spectroscopy. This work represents a great advance in seeking high-performance anodes in SIBs.
Schematics showing a carbon fi ber carbon composite with nano- and micro-interfaces of SiC synthesized by infi ltrating Si-Zr eutectic alloys. The composite is attractive to aerospace applications and aircraft brakes due to its low thermal expansion and mechanical robustness at high temperatures” He et al. Volume 167, 2020, Pages 92-103.Carbon - Volume 171
Cover Highlight: Wetting and brazing of Cf/C composites with Si–Zr eutectic alloys: The formation of nano- and coarse-SiC reaction layers
The wetting and brazing of Cf/C composites with a Si–10Zr eutectic alloy was investigated for the first time. Wetting of the Si–Zr alloy on the Cf/C substrate was studied by applying in-situ variations in contact angle of the droplet placed on the Cf/C substrate with temperature and time. The microstructure and the interfacial structure between the filler and the substrate, and the mechanical properties of the joints were determined using scanning electron microscopy, X-ray diffraction and transmission electron microscopy. The Si–Zr alloy has an equilibrium contact angle of approximately 22° on the Cf/C substrate at 1460 °C, indicating excellent wettability. The liquid Si–Zr alloy can react with the Cf/C substrate by forming nano-SiC and coarse-SiC layers, and promote the wetting behaviour and bonding performance. In addition, the liquid Si–Zr alloy can also infiltrate into the Cf/C substrate along the carbon fibres, causing localised siliconisation and strengthening of the joint. An optimal shear strength of 32 MPa was achieved for the joint at a brazing temperature of 1460 °C for 10 min.
Edge-rich vertical graphene layers with V2O5 nanosheets are designed for highly durable zinc-ion batteries. Zhang et al Volume 172, February 2021, Pages 207-213Carbon - Volume 172
Cover Highlight: Edge-rich vertical graphene nanosheets templating V2O5 for highly durable zinc ion battery
Zinc ion batteries (ZIBs) have attracted increasing attention due to their low cost, high safety and environmental friendliness. However, the simultaneous achievement of long cycle life and high energy density of ZIBs remains an open challenge. In this work, edge-rich cathodes with vertically orientated graphene (VG) nanosheets templating V2O5 nanosheets are designed for high-performance ZIBs. In such a hybrid structure, free-standing VGs on carbon cloth (CC) with non-aggregated characters, open networks and sharp edges as nanotemplates provide fast electron-transfer channels and large accessible surface area to electrolyte. Moreover, edge-rich Zn nanosheets are deposited on CC as anodes to match with edge-rich V2O5/VG/CC cathode. As a result, the assembled aqueous ZIB shows a high capacity of 370 mAh g−1 (at a current density of 0.2 A g−1), high rate capability (capacity retention of over 50% at a current density up to 50 A g−1) and excellent cycle life (showing a high capacity retention of 85% over 5000 cycles).
The image depicts hierarchical mesostructured porous carbons that are able to confi ne polysulfi des and promote ionic transport for Li-S batteries.Carbon - Volume 173
Cover Highlight: A durable lithium–tellurium battery: Effects of carbon pore structure and tellurium content
Lithium-tellurium (Li-Te) batteries have attracted increasing attention as a next-generation energy storage system due to the appealing electrical conductivity and volumetric capacity. Porous carbon hosts are widely used for Te confinement to achieve good electrochemical performance in Li–Te batteries. However, there is a lack of understanding of the effect of carbon pore structure on the performance of Te/C cathodes. Herein, two types of carbons, one with micropores (ASAC25) and the other with mixed micropores and mesopores (ASAC30) are selected as Te hosts to clarify the role of carbon pore structure. Detailed investigations reveal that micropores, rather than mesopores, are critical for effective Te confinement due to complete infiltration of Te in micropores and enhanced Te and C interaction, thus enabling superior stability in ASAC25-Te. The dramatic capacity decline of ASAC30-Te is caused by the dissolution of bulky Te and the loss of active materials in long cycles. ASAC25-Te also achieved exceptional capacity retention of 83.3% after 500 cycles at 1C. Moreover, this work found that the ASAC25 carbon host should be partially filled with Te up to ∼60 wt% to accommodate volume change of Te. The clarification is expected to provide guidance on the further development of high-energy-density Te-based rechargeable batteries.
: The front cover shows magnetite particles between graphene layers that are present within aerogels. The synergistic effects of these materials result in electrode robustness and excellent Li-ion battery performance. Kopuklu et al. Volume 174, 15 April 2021, Pages 158-172Carbon - Volume 174
Cover Highlight: High stability graphene oxide aerogel supported ultrafine Fe3O4 particles with superior performance as a Li-ion battery anode
Herein we report a facile redox deposition method for the construction of a hybrid assembly composed of ultrafine Fe3O4 particles on partially reduced graphene oxide (Fe3O4@PrGO) for Li-ion battery anodes, at which Fe3O4 particles of 20–30 nm size have effectively decorate the PrGO aerogel. The hybrid structure improves the number of active material sites accessible by the electrolyte, and provides an enhanced lithium and electron transport pathway. The material has demonstrated up to 2136 mAhg−1 reversible capacity after 100 cycles at a current density of 0.5 Ag-1 and excellent cyclability at 1 Ag-1 even after 600 cycles of operation. The superior lithium-ion transport kinetics, which is mainly due to effective attachment of the pulverized Fe3O4 particles of 1–2 nm size to the 3D PrGO network, enabled the cell to exhibit 480 mAhg−1 capacity even at a very high discharging rate of 10 Ag-1. The achieved capacity upon electrochemical cycling has been fully recovered even after a long time of ageing, highlighting its potential to replace the conventional graphite as a robust and high-performance anode material.
Cross-linking has a superior ability to enhance the anti-penetration performance of CNT fi lms by producing extra energy dissipating channels.” Xiao et al. Volume 175, 30 April 2021, Pages 478-489Carbon - Volume 175
Cover Highlight: Extraordinary impact resistance of carbon nanotube film with crosslinks under micro-ballistic impact
The crosslinks of carbon nanotubes (CNT) film has been demonstrated to owing the ability to reinforce the quasi-static mechanical properties. But it is unclear whether crosslinks improve the ballistic impact resistance of CNT film. Here, we investigated the impact resistance of CNT film with crosslinks by combining micro-ballistic impact experiments with coarse-grained molecular dynamics (CGMD) simulations. The impact resistance is quantitatively characterized in terms of the specific penetration energy. Meanwhile, the effective enhancement of impact resistance contributed to the crosslinks is directly observed in the experiment. CGMD simulations are employed to unveil the corresponding mechanisms in terms of deformation behavior, energy dissipation mode, and failure behavior. Our results indicate that with the increase of crosslink density, the energy dissipation mode of the CNT film transforms from bending-dominated to stretching-bending-dominated due to enhanced interaction between the adjacent CNTs. This leads to a transformation of perforated morphology from cascaded interfaces sliding to crosslink-restricted deformation with crosslinks. Our simulations also indicate that the length, bending stiffness of CNTs, and film’s thickness play essential roles in the impact resistance of CNT film at various crosslink densities. These results provide a feasible strategy to improve the protective performance of CNT film.
Schematic showing porous carbon containing a majority of micropores, exhibiting high surface area and large pore volume. This porous carbon resulted in excellent structural stability and electrochemical performance of a tellurium/carbon cathode used in lithium-tellurium batteries with the potential of powering electric vehicles. Jian Liu et al. vol 173 pages 11-21, year 2021Carbon - Volume 176
Cover Highlight: A durable lithium–tellurium battery: Effects of carbon pore structure and tellurium content
Lithium-tellurium (Li-Te) batteries have attracted increasing attention as a next-generation energy storage system due to the appealing electrical conductivity and volumetric capacity. Porous carbon hosts are widely used for Te confinement to achieve good electrochemical performance in Li–Te batteries. However, there is a lack of understanding of the effect of carbon pore structure on the performance of Te/C cathodes. Herein, two types of carbons, one with micropores (ASAC25) and the other with mixed micropores and mesopores (ASAC30) are selected as Te hosts to clarify the role of carbon pore structure. Detailed investigations reveal that micropores, rather than mesopores, are critical for effective Te confinement due to complete infiltration of Te in micropores and enhanced Te and C interaction, thus enabling superior stability in ASAC25-Te. The dramatic capacity decline of ASAC30-Te is caused by the dissolution of bulky Te and the loss of active materials in long cycles. ASAC25-Te also achieved exceptional capacity retention of 83.3% after 500 cycles at 1C. Moreover, this work found that the ASAC25 carbon host should be partially filled with Te up to ∼60 wt% to accommodate volume change of Te. The clarification is expected to provide guidance on the further development of high-energy-density Te-based rechargeable batteries.
The ultralow friction of H-DLC fi lms originates from concerted effects of multiple dynamic changes involving nanoscrolls/ graphite layers, contact area after surface wear and initial graphitization of the worn subsurface.Carbon - Volume 177
Cover Highlight: Carbon fibre electrodes for ultra long cycle life pseudocapacitors by engineering the nano-structure of vertical graphene and manganese dioxides
Critical to the applications of pseudocapacitors is the cycling performance of electrodes. Here, we present a new carbon fibre electrode enhanced by multilayer structure of vertical graphene (VG) and manganese dioxide (MnO2) to achieve a cycling performance at a very high areal capacitance (546.3 mF/cm2) that outperforms most of the reported pseudocapacitors in the literature. Particularly, this multilayer electrode is able to retain 99.3% of its initial capacitance after 10,000 cycles at scan rate of 200 mV/s. The retention ratio is significantly higher than the state-of-art value. In addition, this electrode shows excellent rate performance (75.4% capacitance retention for current density from 1 to 10 mA/cm2). This exceptionally high stability at high capacitance and rate performance originates from the multilayer electrode’s effectiveness in self-replenishing the degraded MnO2 in the outer layer. The microcracks and micro holes induced in the VG layer by electrical charge/discharge cycling enable the inner layer MnO2 to progressively participate in the redox reaction. Results from energy dispersive spectroscopy, X-ray photoelectron, and Raman spectroscopy confirm the self-replenishing mechanism responsible for the exceptionally stable performance. The new multilayer electrode designed herein provides a new route for improving the cycling performance of pseudocapacitors.
Schematic showing the reduction of graphene oxide by in-situ thermal transmission electron microscopy and electron energy loss spectroscopy. Raul Arenal et al, CARBON, 30 June 2021 issue, pages 477-487.Carbon - Volume 178
Cover Highlight: Detailed thermal reduction analyses of graphene oxide via in-situ TEM/EELS studies
We report an in-depth study of the reduction of graphene oxide (GO) by in-situ thermal transmission electron microscopy (TEM) analysis. In-situ heating high-resolution TEM (HRTEM) imaging and electron energy-loss spectroscopy (EELS) measurements have been combined to identify the transformations of different oxygen functional groups, the desorption of physisorbed and chemisorbed water and the graphitisation as a function of the temperature in the range from 70 up to 1200 °C. A model for the general removal of water and OFGs is proposed based on different chemical and physical parameters that have been monitored. All this unique information provides a detailed roadmap of the thermal behaviour of GO at an extended range of temperature. This is not only of interest to understand the thermal reduction process of GO but also of critical relevance to the response of GO in applications when exposed to thermal effects.