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Here, a universal template-activation strategy is proposed to prepare two different types of porous carbonaceous materials for potassium ion hybrid capacitor (PIHC) anode and cathode, which is realized by only changing the type of cation (Na + and K + ) in the polysilicic acid-organic mixed hydrogel precursor originating from adding organic acid into Na 2 SiO 3 and K 2 SiO 3 solution, respectively. TG-IR data demonstrate that K + exhibits a stronger etching ability for activating carbonaceous materials during the annealing process. Accordingly, a 3D carbon anode obtained with the assistance of NaOH (NPC-500) exhibits abundant edge-N doping (8.14 at%), displaying a high K-storage capacity of 314.1 mA h g -1 at 0.2 A g -1 and a capacity of 219.3 mA h g -1 at 10 A g -1 after 10000 cycles. A porous carbon particles cathode prepared in the presence of KOH (KCP-800) shows a high specific surface area (1326.8 m 2 g -1 ), contributing to high PF 6 - (de)adsorb capacity of 103.0 mA h g -1 at 1 A g -1 . Remarkably, the assembled NPC//KCP PIHC delivers a high energy density of 137.7 W h kg -1 at a power density of 275.4 W kg -1 even over 20 000 cycles., (© 2022 Wiley-VCH GmbH.)

Fe3O4@C core-shell nanorings (R-Fe3O4@C) were fabricated by a synchronous reduction and carbon deposition process. As the anodes for lithium-ion batteries, these R-Fe3O4@C exhibit a high capacity, excellent cycling stability and good rate performance. This ring-shaped core-shell nanostructure design may pave the way to enhance electrochemical performances of electrode materials.

Novel sandwich-like porous carbon nanosheet-supported hexagonal carbon micro-flakes (WPWMC) are fabricated via a one-step hydrothermal route at 700 °C with polyethylene as the precursor and magnesium as the inducer. Through various characterizations, it is confirmed that the hexagonal carbon micro-flakes exhibit (002) orientation, which exposes abundant edge active sites and shortens the K+ transmission path. Moreover, the inside cross-linked carbon nanosheets with abundant pores can accelerate ion diffusion and increase the capacitive contribution. The WPWMC anode displays a high reversible capacity (528.7 mA h g−1 at 0.2 A g−1), good rate capability (152.7 mA h g−1 at 10 A g−1) and long-term cycle stability (112.1 mA h g−1 at 5 A g−1 after 10 000 cycles). Furthermore, the WPWMC//CMK-3 hybrid capacitor exhibits an energy density of 222.7 W h kg−1 at 446.2 W kg−1. This work provides an idea for transforming waste plastic into value-added materials. [ABSTRACT FROM AUTHOR]

Abstract Hollow spheres, hollow capsules and solid spheres of carbon were selectively synthesized by Mg-reduction of hexachlorobutadiene at appropriate reaction conditions. X-ray powder diffraction and Raman spectra reveal that the as-prepared materials have a well-ordered structure. A possible formation mechanism has been proposed.

Main observation and conclusion: There is no doubt that SiOx and carbon composite is one of the promising anode materials for lithium‐ion batteries owing to its high capacity and rational cycling stability. Herein, we report a sol‐gel synthesis followed by molten salt carbonization route to fabricate graphene‐like carbon nanosheet wrapped SiOx/C submicrospheres (SiOx/C@2D‐C). The in‐situ generated carbon nanosheets under molten salt condition can further improve the electroconductivity, restrain the volumetric expansion and guarantee the structural integrity of the electrode. As a result, the as‐obtained SiOx/C@2D‐C delivers a discharge capacity of 559 mAh·g−1 at 0.5 A·g−1 after 200 cycles and 548 mAh·g–1 at 1.0 A·g−1 even after 1000 cycles. The full cell assembled with SiOx/C@2D‐C as anode and commercial LiFePO4 as cathode can achieve an energy density of 200 Wh·kg−1 and maintain a capacity of 66.7% after 100 cycles with a working potential of 2.8 V. The approach is simple and cost effective, which is promising for mass production of SiOx‐based materials for high energy LIBs. [ABSTRACT FROM AUTHOR]

A highly oriented mesoporous graphitic carbon nanospring (OGCS) with graphitic layers that are perpendicular to the axis is prepared by hydrothermal treatment of epoxy resin at 500 °C and annealing at 1400 °C. Water plays an important role in not only forming the graphitic carbon nanospring with a high [002] orientation and a large amount of active edge‐plane sites, but also in the generation of the mesoporous structure, which facilitate fast K‐ion adsorption and diffusion. In situ and ex situ measurements confirm that OGCS undergoes K‐adsorption in mesopores and then K‐intercalation in the graphite layer to form KC8 with a low discharge voltage. The spring‐like nanostructure can expand one‐dimensionally along the axial direction to accommodate the volume variation. The OGCS electrode thus shows a much better K‐storage performance than that of unoriented graphitic carbon. [ABSTRACT FROM AUTHOR]

MoSe2 grown on N,P-co-doped carbon nanosheets is synthesized by a solvothermal reaction followed with a high-temperature calcination. This composite has an interlayer spacing of MoSe2 expanded to facilitate sodium-ion diffusion, MoSe2 immobilized on carbon nanosheets to improve charge-transfer kinetics, and N and P incorporated into carbon to enhance its interaction with active species upon cycling. These features greatly improve the electrochemical performance of this composite, as compared to all the controls. It presents a specific capacity of 378 mAh g−1 after 1000 cycles at 0.5 A g−1, corresponding to 87% of the capacity at the second cycle. Ex situ Raman spectra and high-resolution transmission electron microscopy images confirm that it is element Se, rather than MoSe2, formed after the charging process. The interaction of the active species with modified carbon is simulated using density functional theory to explain this excellent stability. The superior rate capability, where the capacity at 15 A g−1 equals ≈55% of that at 0.5 A g−1, could be associated with the significant contribution of pseudocapacitance. By pairing with homemade Na3V2(PO4)3/C, this composite also exhibits excellent performances in full cells. [ABSTRACT FROM AUTHOR]

For lithium-selenium batteries, commercial applications are hindered by the inferior electrical conductivity of selenium and the low utilization ratio of the active selenium. Here, we report a new baked-in-salt approach to enable Se to better infiltrate into metal-complex-derived porous carbon (Se/MnMC-B). The approach uses the confined, narrow space that is sandwiched between two compact NaCl solid disks, thus avoiding the need for protection with argon or a vacuum environment during processing. The electrochemical properties for both lithium and sodium storage of our Se/MnMC-B cathode were found to be outstanding. For lithium storage, the Se/MnMC-B cathode (with 72% selenium loading) exhibited a capacity of 580 mA h g−1 after 1000 cycles at 1 C, and an excellent rate capability was achieved at 20 C and 510 mA h g−1. For sodium storage, a specific capacity of 535 mA h g−1 was achieved at 0.1 C after 150 cycles. These results demonstrate the potential of this approach as a new effective general synthesis method for confining other low melting point materials into a porous carbon matrix. [ABSTRACT FROM AUTHOR]

Ferric chloride-graphite intercalation compounds (FeCl3-GICs) with stage 1 and stage 2 structures were synthesized by reacting FeCl3 and expanded graphite (EG) in air in a stainless-steel autoclave. As rechargeable Li-ion batteries, these FeCl3-GICs exhibit high capacity, excellent cycling stability, and superior rate capability, which could be attributed to their unique intercalation features. This work may enable new possibilities for the fabrication of Li-ion batteries. [ABSTRACT FROM AUTHOR]

A facile method is presented for the large-scale preparation of rationally designed mesocrystalline MnO@carbon core-shell nanowires with a jointed appearance. The nanostructures have a unique arrangement of internally encapsulated highly oriented and interconnected MnO nanorods and graphitized carbon layers forming an external coating. Based on a comparison and analysis of the crystal structures of MnOOH, Mn2O3, and MnO@C, we propose a sequential topotactic transformation of the corresponding precursors to the products. Very interestingly, the individual mesoporous single-crystalline MnO nanorods are strongly interconnected and maintain the same crystallographic orientation, which is a typical feature of mesocrystals. When tested for their applicability to Li-ion batteries (LIB), the MnO@carbon core-shell nanowires showed excellent capacity retention, superior cycling performance, and high rate capability. Specifically, the MnO@carbon core-shell nanostructures could deliver reversible capacities as high as 801 mA h g−1 at a high current density of 500 mA g−1, with excellent electrochemical stability after testing over 200 cycles, indicating their potential application in LIBs. The remarkable electrochemical performance can mainly be attributed to the highly uniform carbon layer around the MnO nanowires, which is not only effective in buffering the structural strain and volume variations of anodes during repeated electrochemical reactions, but also greatly enhances the conductivity of the electrode material. Our results confirm the feasibility of using these rationally designed composite materials for practical applications. The present strategy is simple but very effective, and appears to be sufficiently versatile to be extended to other high-capacity electrode materials with large volume variations and low electrical conductivities. [ABSTRACT FROM AUTHOR]

Three-dimensional hierarchical dendritic carbon structures with high densities of secondary carbon nanosheets have been fabricated using a solvothermal growth via reacting metal Na with tetrachloromethane in 200°C on Cu ribbon. Field-emission scanning electron microscopy and transmission electron microscopy images of the as-prepared sample shows that 3D hierarchical dendritic carbon structures are composed of carbon nanosheets with the thickness of about 20 nm. The powder X-ray diffraction and Raman spectra reveal the low graphitisation degree of the as-prepared sample. A possible formation mechanism has been proposed. [ABSTRACT FROM AUTHOR]

The low capacity and unsatisfactory rate capability of hard carbon still restricts its practical application for Li/K‐ion batteries. Herein, a low‐cost and large‐scale method is developed to fabricate phosphorus‐doped hard carbon (PHC‐700) by crosslinking phosphoric acid and epoxy resin and followed by annealing at 700 °C. H3PO4 acts not only as a crosslinker to solidify epoxy resin for promoting the degree of graphitization and lowering the specific surface area, but also as phosphorus source for forming PC and PO bonds, thus providing more active sites for Li/K storage. As a result, the PHC‐700 electrode delivers a highly reversible capacity of 1294.8 mA h g−1 at 0.1 A g−1 and a capacity of 214 mA h g−1 after 10 000 cycles at 10 A g−1. As for potassium‐ion batteries, PHC‐700 exhibits a reversible capacity of 381.9 mA h g−1 at 0.1 A g−1 and a capacity of 260 mA h g−1 after 1000 cycles at 0.2 A g−1. In situ Raman and in situ NMR measurements reveal that the P‐containing bonds can enhance the adsorption to alkali metal ions, and the PC bond can participate in electrochemical redox reaction by forming LixPCy. Additionally, P‐doped hard carbon shows better structural/interfacial stability for improved long‐term cycling stability. [ABSTRACT FROM AUTHOR]

Abstract: A shape-controlled synthesis of carbon-encapsulated Fe3O4 core/shell (Fe3O4@C) composites is reported in this paper. By tuning the reaction temperature from 500°C to 700°C and the amount of ammonium acid carbonate (1.0g, 0.5g and 2.0g) in a sealed reaction system, Fe3O4@C composites with hexapod-like, flake-like, and chain-like morphologies have been successfully obtained using ferrocene as the precursor. Corresponding hollow carbon structures can be obtained by acid treatments. The three kinds of Fe3O4@C composites show ferromagnetic properties at room temperature, while their saturation magnetizations and coercivities are obviously different from each other, due to the various shapes and structures. Possible formation processes of these Fe3O4@C composites and corresponding hollow carbon materials are discussed. The experimental results indicate that the reaction temperature and the amount of ammonium acid carbonate play key roles in the shape-controlled synthesis of hexapod-like, flake-like and chain-like Fe3O4@C composites. [Copyright &y& Elsevier]

SiO x is a promising anode material for lithium-ion batteries owing to its smaller volume expansion and longer lifespan than silicon. However, its development is severely hampered by the sluggish reaction kinetics and large volume changes. Herein, a facile and scalable synthesis of exfoliated N-doped carbon nanoslices supported SiO x (SiO x /NCS) is developed by a melamine assisted ball milling and annealing procedure. The principle of melamine in exfoliating graphite is demonstrated by contrast experiments and theoretical calculations. It is found NCS acts as matrix to enhance the reaction kinetics and accommodate the volume changes which contributes to the significant improvements of cycling performance and rate capability. The SiO x /NCS anode exhibits ultrastable cycling performance (∼900 mAh g−1 over 600 cycles at 1 A g−1) and superior rate capability (565 mAh g−1 at 5 A g−1). At a high mass loading of 3.3 mg cm−2, an ultrahigh areal capacity of 2.4 mAh cm−2 is obtained after 200 cycles. Moreover, the potential application of SiO x /NCS anode in LIBs is also confirmed by the good performance of SiO x /NCS//NCM111 full cells. [Display omitted] • SiO x /NCS composite is synthesized via a facile and scalable route. • The principle of melamine in exfoliating graphite is theoretically demonstrated. • SiO x /NCS composite exhibits ∼900 mAh g−1 over 600 cycles at 1.0 A g−1. • SiO x /NCS shows high areal capacity of 2.4 mAh cm−2 at 3.3 mg cm−2 after 200 cycles. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: There is no doubt that SiOx and carbon composite is one of the promising anode materials for lithium‐ion batteries owing to its high capacity and rational cycling stability. Herein, we report a sol‐gel synthesis followed by molten salt carbonization route to fabricate graphene‐like carbon nanosheet wrapped SiOx/C submicrospheres (SiOx/C@2D‐C). The in‐situ generated carbon nanosheets under molten salt condition can further improve the electroconductivity, restrain the volumetric expansion and guarantee the structural integrity of the electrode. As a result, the as‐obtained SiOx/C@2D‐C delivers a discharge capacity of 559 mAh·g−1 at 0.5 A·g−1 after 200 cycles and 548 mAh·g–1 at 1.0 A·g−1 even after 1000 cycles. The full cell assembled with SiOx/C@2D‐C as anode and commercial LiFePO4 as cathode can achieve an energy density of 200 Wh·kg−1 and maintain a capacity of 66.7% after 100 cycles with a working potential of 2.8 V. The approach is simple and cost effective, which is promising for mass production of SiOx‐based materials for high energy LIBs. [ABSTRACT FROM AUTHOR]

• Li 3 VO 4 nanoparticles in porous N-doped carbon are synthesized. • Porous N-doped carbon is derived from melamine and citric acid. • Porous N-doped carbon and Li 3 VO 4 nanoparticles together give superior performances. • This composite exhibits a capacity of 236.6 mAh g−1 after 1000 cycles at 4.0 A g−1. • This composite coupled with LiCoO 2 as full cells are examined. Li 3 VO 4 nanoparticles in N-doped carbon with porous structure are synthesized using supermolecular aggregates formed by melamine and citric acid as the nitrogen source, via a dry-freezing process, followed with a calcination. Nitrogen doping enhances the interaction between Li 3 VO 4 and carbon, reduces the charge-transfer resistance over the interface, and restrains the pulverization and aggregation upon cycling. The design of porous structure accelerates the permeation of electrolyte and increases the contact between active materials and electrolyte. The synergistic effects between N-doped carbon and porous structure significantly improve the electrochemical performances. Thus, this composite delivers a capacity of 405.1 mAh g−1 at 0.1 A g−1 or 199.9 mAh g−1 at 10.0 A g−1 within 0.2–3.0 V. After 1000 cycles at 4.0 A g−1, the specific capacity is still kept as 236.6 mAh g−1. By pairing with commercial LiCoO 2 , this composite delivers a high energy density of 195.05 Wh kg−1 total at 70.52 W kg−1 total , and 94.06 Wh kg−1 total at 3.9 kW kg−1 total. [ABSTRACT FROM AUTHOR]

The dual-functional carbons are decorated on porous Si microspheres with interpenetrated Si@C channel and stable outer carbon interphase, which are employed to boost the lithium storage and remedy the vital shortcomings of the Si anode, in terms of unstable solid−electrolyte interphase layer, terrible electronic conductivity, huge volume changes as well as bad cycling or rate capability. In this designed composite, the outer carbon layer can perfectly maintain the structure stability and avoid direct contact of Si with electrolyte during cycling, thus resulting in stable solid−electrolyte interphase film and improved initial coulombic efficiency. Furthermore, the inner carbon layer coated directly onto the porous Si framework can effectively enhance the overall conductivity, let the lithium insert fully and endow the composite with higher capacity in half and full cell. As a result, the as-prepared porous Si/C microspheres deliver a reversible capacity of 1660 mAh g−1 at 0.2 A g−1 after 100 cycles and 826.8 mAh g−1 at 2 A g−1 after 200 cycles. Dual-functional carbons are developed to remedy the vital shortcomings of the commercial Si anode, in terms of unstable solid−electrolyte interphase layer, terrible electronic conductivity, huge volume changes as well as bad cycling or rate capability. Image 1 [ABSTRACT FROM AUTHOR]

Abstract: Porous nitrogen-doped carbon vegetable-sponges (N-DCSs) have been fabricated by chemical treatment of the Cu@C precursors using HNO3 for the first time. The obtained N-DCSs are porous three-dimensional (3D)-structure and similar to numerous agglomerated fluffy micro-vegetable-sponges. When the precursors are treated by H2SO4, carbon vegetable-sponges (CSs) without nitrogen doping are prepared. As anode materials in lithium ion batteries, the as-prepared N-DCSs show improved Li-storage capacity and cycling stability as compared with the pure CSs. They offer 870mAhg−1 at 0.5Ag−1 after 300 cycles and high reversible capacity with 910mAhg−1 at 0.2Ag−1 after cycled at different current densities, which are much higher than those of CSs. It is envisaged that the large surface area, unique 3D porous nanostructure and appropriate nitrogen doping are favorable for the superior electrochemical properties of N-DCSs. [Copyright &y& Elsevier]

Nitrogen-doped carbon (NC) materials were prepared by pyrolyzing pyrrole in the presence of basic magnesium carbonate at 400–700°C. Three kinds of C–N bonding patterns, namely pyridinic-, pyrrolic-, and graphitic-type N, are present in NC products. The pyrolysis temperature has an intensive influence on the contents of three nitrogen species. It is found that NC-700, containing the highest content (3.87at%) of graphitic-type N, exhibits the best discrimination ability for ascorbic acid (AA), dopamine (DA), and uric acid (UA). Differential pulse voltammetry study reveal that the detection limit (S/N=3) can reach 0.090µM for DA even in the presence of 1000µM AA and 200µM UA. [ABSTRACT FROM AUTHOR]

Abstract: The Li2MnSiO4/C nanocomposite has been successfully synthesized at a relatively low temperature of 650 °C by a facile solid-state reaction using citric acid as the carbon source. The highly crystalline Li2MnSiO4 nanoparticles in the size of 20–50 nm are coated by a uniform carbon layer in a thickness of 2–5 nm. At a rate of 0.05 C, the Li2MnSiO4/C nanocomposite exhibits a discharge specific capacity as high as 268 mAh g−1 for the first cycle and a reversible capacity of about 136 mAh g−1 after 140 cycles at room temperature. Meanwhile, an improved rate performance is achieved by the Li2MnSiO4/C nanocomposite. These superior electrochemical properties could be attributed to the nanoscale particle size and the enhanced electronic conductivity. [Copyright &y& Elsevier]

Abstract: Fe3O4/C composites have been prepared by sucrose calcining with Fe3O4 particles obtained from ferrous oxalate decomposition. The scanning electron microscopy (SEM) images show that Fe3O4 nanoparticles (Fe3O4 NPS) with average size of 200nm are embedded in the three-dimensional (3D) carbon-framework. As an anode material for rechargeable lithium-ion batteries, the Fe3O4/C composite delivers a reversible capacity of 773mAhg−1 at a current density of 924mAg−1 after 200 cycles, higher than that of the bare Fe3O4 NPS which only retain a capacity of 350mAhg−1. When the current density rises to 1848mAg−1, Fe3O4/C material still remains 670mAhg−1 even after 400 cycles. The enhanced high-rate performance can be attributed to the 3D carbon-framework, which improves the electric conductivity, relaxes the strain stress and prevents the aggregation of Fe3O4 particles during the charge/discharge process. [Copyright &y& Elsevier]

Abstract: Hollow carbon octahedra with an average size of 300nm and a shell thickness of 2.5nm were prepared by a reaction starting from ferrocene and Mg(CH3COO)2·4H2O at 700°C for 10h. They became compressed and turned into deflated balloon-like octahedra when the reaction time was increased to 16h. It was proposed that the gas pressure generated during the reaction process induced the transformation from broken carbon hollow octahedra into deflated balloon-like compressed octahedra. X-ray powder diffraction and Raman spectroscopy indicate that the as-obtained carbon products possess a graphitic structure and high-resolution transmission electron microscopy images indicate that they have low crystallinity. Their application as an electrode shows reversible capacity of 353mAhg−1 after 100 cycles in the charge/discharge experiments of secondary lithium ion batteries. [Copyright &y& Elsevier]

Abstract: Honeycomb-like graphitic macroporous carbon (HGMC) was synthesized by means of pyrolysis of NH4HCO3 using Mg powder as reductant in an autoclave at 550°C. The characterization of structure and morphology was carried out by X-ray diffraction (XRD), Raman spectrum, field-emission scanning electron microscopy (FESEM), and (High-resolution) transmission electron microscope [(HR)TEM]. The results of nitrogen adsorption–desorption indicate that the products are macropore materials with the pore size of 1–3μm, and the Brunauer–Emett–Teller (BET) surface area was 14m2/g. As a typical morphology, the possible growth process of HGMC was also investigated and discussed. The experimental results show that the in situ formed MgO microparticles play a template role during the HGMC formation. [Copyright &y& Elsevier]

Abstract: Leaf-like carbon sheets have been obtained by the pyrolysis of dichloromethane and ferrocene in an autoclave in 300–600°C on Cu ribbons for 90min. The thickness of the sheets could be controlled from 50 to 200nm by adjusting the experimental parameters. The formation process was studied by observing product-evolution utilizing the real-time imaging capabilities of emission scanning electron microscope, and it is considered that Diffusion-Limited Aggregation mechanism could be responsible for their growth. Thermo-gravimetric analysis curves show that the initial thermal decomposition temperature of the carbon sheets increases from 300 to 420°C with the increasing preparation temperature. The Brunauer–Emmett–Teller specific surface area was 398m2/g and with a narrow pore distribution in the range of 2–5nm. By changing the carbon sources, solid carbon spheres as well as chain-like solid carbon spheres (3–5μm) could be selectively prepared using one-pot reactions. [Copyright &y& Elsevier]

Abstract: A Cu@carbon (Cu@C) spherical core–shell structure has been synthesized from carbonaceous matrices containing embedded copper particles by thermal treatment at 600°C under an argon atmosphere. The matrices are prepared by reducing CuCl2 with vitamin C (VC) in the existence of polyacrylamide (PAM) at 180°C, accompanied by the partial carbonization of VC. It is found that small Cu nanoparticles with diameters of ∼3nm homogeneously disperse in the carbonaceous matrices. Subsequent thermal treatment at 600°C under an argon atmosphere leads to the diffusion of these Cu nanoparticles and further carbonization of carbonaceous matrices to form a Cu@C core–shell structure. The core–shell ratio can be controlled by varying the dose of CuCl2, VC, or PAM. It is found that the carbon shell can effectively shield the metallic Cu core from oxidation in the mixed solution of dilute hydrogen peroxide and nitric acid. [Copyright &y& Elsevier]

Abstract: Chain Fe3O4 nanoparticles encapsulated in worm-shaped carbon shell (defined as “WCCIOs”) were in situ synthesized by copyrolysis of polyethylene, malated-polypropylene and ferrocene in the presence of 10 ml H2O in an autoclave at 700 ∘C for 12 h. The shell thicknesses of these WCCIOs are about 180 nm and the lengths reach up to several micrometers. And the average size of the Fe3O4 nanoparticles inside the worm-shaped carbon shell is about 100 nm. The shapes and compositions of WCCIOs were simply controlled by adjusting the reaction temperatures and relative amounts of the precursors. On the basis of the experimental results, the formation process of the WCCIOs is discussed. The WCCIOs possess well acid resistance, which differs from those reported previously: the nanoparticles were embedded inside the thicker carbon shell. It is also found that the coercivity (Hc) value of the WCCIOs is much higher than that of bare Fe3O4 nanoparticles and bulk Fe3O4. [Copyright &y& Elsevier]

Abstract: Monodispersed Fe3O4 nanoplates between two carbon films were synthesized by pyrolyzing ferrocene and sodium oxalate in a stainless steel autoclave of 64mL capacity at 600°C. The Fe3O4 nanoplates are triangular single crystals, sometimes truncated, with edge lengths ranging from 50 to 100nm. In an experiment where the pressure of the reaction system was increased, carbon-encapsulated Fe3O4 nanorods were obtained. The inner Fe3O4 nanorods are also single crystal with a diameter ca. 100nm and lengths up to 1μm. A possible formation mechanism for the layered structure is proposed based on the experimental results. Magnetic property measurements show that the layered nanoplates display ferromagnetic properties at room temperature. [Copyright &y& Elsevier]

Abstract: Uniform submicron hydrogenated amorphous carbon “test tubes”, both empty and containing nickel particles, were synthesized via the self-catalysis-decomposition of Ni(Hdmg)2 (Hdmg=dimethylglyoxime anion) at 250°C. Since one end of the tubular carbon is always open but the other end is closed, they look like “test tubes”. Transmission electron microscopy images show they have an average inner (outer) diameter of 560nm (740nm) and an average length of around 5.4μm. They were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy, Raman spectroscopy and thermogravimetric analysis. The results indicated that the “test tubes” consist of amorphous hydrogenated carbon. The magnetic properties of the contained nickel reached a coercivity as high as H c ≈153Oe and showed a remarkable decrease of saturation magnetization. The reaction temperature and solvent are of great importance in determining the final structures. A possible formation mechanism was discussed. [Copyright &y& Elsevier]

Abstract: Amorphous carbon nanotubes and Fe/C coaxial nanocables were synthesized by a solvothermal treatment of ferrocene and sulfur. In this process, the amount of sulfur played an important role in the formation of products. When the molar ratio of ferrocene to sulfur was 1:1, the products were amorphous carbon nanotubes and Fe/C coaxial nanocables. And as the ratio was decreased to 1:2, amorphous carbon nanotubes were the main products. [Copyright &y& Elsevier]

Abstract: Coral-like accretion of hollow carbon microspheres with thin walls has been successfully synthesized through a carbon dissolution–precipitation process, where the decomposition of cyclohexane on nickel powder, at 550°C in a sealed system, and is followed by rapid cooling. The final product is tens of microns in size with smooth and uniformly thin shell thickness of approximately 3–4nm. XRD, FESEM, EDX, TEM, HRTEM and Raman spectra were used to characterize the products. The effects of reaction temperature, type of carbon source and cooling process on the formation of the final products have been studied, and a possible formation mechanism for the coral-like product has been proposed. This coral-like accretion of large capacity hollow carbon microspheres has potential applications as a catalyst carrier, in storage or protection of unstable organic materials and microreactors. [Copyright &y& Elsevier]

Abstract: Carbon nanofibers (CNFs) have been synthesized by co-catalyst deoxidization process by a reaction between C2H5OC2H5, Zn and Fe powder at 650°C for 10h. These nanofibers exhibit diameters of ∼80nm and lengths ranging from several micrometers to tens of micrometers. X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy indicate that as-prepared CNFs possess low graphitic crystallinity. The resultant CNFs as electrode shows capacity of ∼220mAh/g and high reversibility with little hysteresis in the insertion/deintercalation reactions of lithium-ion. In addition, the possible growth of CNFs is discussed. [Copyright &y& Elsevier]

Abstract: Two kinds of new morphology of carbon nanomaterials, carbon nanocables and branched-nanobelts can been produced by pyrolyzing ethylene glycol monvethyl ether (CH3CH2OCH2CH2OH) with Fe as catalyst at 650–700°C. The carbon nanocables are made of two parts, the interior carbon nanowires encapsulated in the outer carbon nanotubes. For the nanocables, HRTEM images reveal that the crystallinity of the outer carbon nanotubes is better than that of the interior carbon nanowires. HRTEM image shows that the junctions of the branched-nanobelts are composed of graphitic layers that are almost perpendicular to the respective axis of the branched-nanobelts. The catalysts, temperature and reaction time were investigated. The possible growth mechanism for the as-synthesized carbon structures is discussed. [Copyright &y& Elsevier]

Abstract: Helically coiled carbon nanotubes (HCNTs) with diameter of 50–100nm were obtained on a large scale by reducing ethyl ether with metallic zinc at 700°C. As the temperature was raised to 750°C, most of the products were solid carbon spheres besides HCNTs. X-ray diffraction pattern and the Raman spectroscopy indicate that the product is graphite phase. HCNTs with diameter of 50–100nm in large quantity were found in the products. [Copyright &y& Elsevier]

Carbon nanotubes were synthesized via a single-source precursor route at 500 °C, using iron carbonyl both as carbon source and catalyst. The X-ray power diffraction pattern indicates that the products are hexagonal graphite. Transmission electron microscope (TEM) images of the sample reveal carbon nanotubes with an average inner (outer) diameter of 30 nm (60 nm). High-resolution TEM indicates that fabrication of the carbon nanotube walls was composed of ca. 40 graphene layers. The Raman spectrum shows two strong peaks at 1587 and 1346 cm−1, corresponding to the typical Raman peaks of graphitized carbon nanotubes. This method avoids the separation of raw material from solvent and simplifies the operation process. At the same time, the research provides a new route to large-scale synthesis of carbon nanotubes. [Copyright &y& Elsevier]

Molybdenum carbide (Mo2C) has been synthesized via a sodium co-reduction of molybdenum pentachloride (MoCl5) and carbon tetrabromide (CBr4) in benzene at 350 °C for 12 h. X-ray diffraction (XRD) pattern indicated that the product was mainly hexagonal Mo2C with a small amount of cubic Mo2C. The lattice constants of the hexagonal Mo2C were a=3.009 and c=4.736 A˚. Transmission electron microscopy (TEM) study showed that the product consisted of slightly conglomerated particles of about 30 nm in size. [Copyright &y& Elsevier]

• Freestanding carbon paper confined with ultrafine lithiophilic TiO 2 is in-situ synthesized from MXene and CO 2. • Freestanding C/TiO 2 paper is firstly employed as dendrite-free Li metal anodic host. • The growth behaviors of metallic Li on C/TiO 2 is systematically probed. • Lithiophilic TiO 2 seeds and conductive 3D carbon synergistically induce dendrite-free Li deposition. • C/TiO 2 @Li paper enables full cell with improved electrochemical performance. Lithium (Li) metal anode is deemed as one of the most fascinating anodes due to its high energy density. Nonetheless, low Coulombic efficiency and safety issues caused by detrimental Li dendrites growth severely hamper its practical application. Herein, we construct an ultrafine TiO 2 confined in 3D freestanding carbon paper by one-step green in-situ oxidation of Ti 3 C 2 T x MXene film with greenhouse gas CO 2. The lithiophilic TiO 2 seeds and freestanding 3D carbon matrix can synergistically induce uniform Li deposition and buffer the volume changes during lithium striping and deposition, which ensure improved electrochemical performance with high Coulombic efficiency and low overpotential, etc. The growth process of metallic Li on C/TiO 2 is also systematically investigated. Moreover, the C/TiO 2 @Li||LiFePO 4 full batteries present a stable cycling performance over 250cycles at 1.0C and superior rate performance. Additionally, this work proposes an alternative way to utilize CO 2 , which may alleviate greenhouse effect and boost sustainable development. These results may be useful for both the design of dendrite-free lithium metal batteries and the sustainable utilizing of CO 2. [ABSTRACT FROM AUTHOR]

• C PVP+C2H2 /Bi/rGO is fabricated by a solvothermal and subsequent chemical vapor deposition strategy. • The dual carbon can improve the conductivity and suppress the huge volume changes of Bi. • The C PVP+C2H2 /Bi/rGO exhibits excellent cycling performance and rate capability for Na-ion batteries. • The electrochemical performance of C PVP+C2H2 /Bi/rGO is better than C PVP /Bi/rGO. • The assembled full battery with C PVP+C2H2 /Bi/rGO as anode presents good electrochemical performance. Bismuth as alloy-based anode material has a high theoretical specific capacity (385 mAh g −1) and volumetric capacity (3800 mAh cm−3). However, its severe volume expansion during the alloying process will cause structural collapse and capacity degradation. In this work, dual carbon materials containing outmost thin carbon layer and graphene are employed to modify bismuth nanospheres to form a sandwich-like carbon/bismuth/reduced graphene oxide composite (C PVP+C2H2 /Bi/rGO), which is fabricated via a facile solvothermal method and subsequent chemical vapor deposition (CVD) strategy. The thin carbon layer coated on the surface of Bi nanoparticles can effectively suppress the huge volume changes of Bi. The graphene oxide as a conductive matrix favors the successful loading of Bi nanospheres, which limits the particle aggregation of Bi upon cycling. The dual carbon also can improve the conductivity of the overall electrode. As anode materials for sodium-ion batteries, the C PVP+C2H2 /Bi/rGO shows excellent sodium storage performance, better than C PVP /Bi/rGO. At a high current density of 5 A g −1, this electrode can retain a capacity of up to 327.6 mAh g −1 after 1200 cycles. The assembled full battery with C PVP+C2H2 /Bi/rGO as anode and Na 3 V 2 (PO 4) 3 /rGO as cathode also presents good electrochemical performance. The outstanding electrochemical performance of C PVP+C2H2 /Bi/rGO is attributed to the well-designed sandwich-like composite structure and synergistic effect of dual carbon and Bi nanospheres. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract: Graphene nanosheets (GS) had been solvothermally synthesized through reducing hexachloro-1,3-butadiene (C4Cl6) by metallic sodium (Na) in polyethylene glycol-600 (PEG-600) at 300°C. Atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM) investigations indicated that 1–3 graphite layers could be observed. The Raman spectrum showed that the peak of 2D band at 2693cm−1 of GS had a smaller wave number and stronger intensity compared to the 2717cm−1 of commercial graphitic flakes. Meanwhile, the ID/IG value of GS was 0.40 indicating a lower density of defects of GS. The possible reaction process was that C4Cl6 was dechlorinated by Na in the presence of PEG-600 to produce carbon framework, then these newly produced carbon framework would connect to each other to form the hexagonal network of graphene. [Copyright &y& Elsevier]

Abstract: Urchin-like Fe3BO5@carbon core–shell structures (defined as “FBOC”) have been fabricated by a one-step co-pyrolysis method using boric acid and ferrocene as raw materials. This complex architecture is composed of high-density Fe3BO5@carbon nanocables that stand on Fe3BO5@carbon structure. After removing the Fe3BO5, hollow urchin-like carbon material was obtained. In the reaction process, B2O3 and H2O that decomposed from H3BO3 have synergistic effect on the formation of urchin-like structures. It is found that urchin-like structures can also be obtained when other materials that can release H2O and B2O3 react with ferrocene. The influences of the reaction conditions on the preparation of FBOC have been discussed in detail. [Copyright &y& Elsevier]

Lithium–sulfur (Li–S) batteries are promising energy-storage technology, but a major technical issue is the shuttling of soluble polysulfides between electrodes, resulting in rapid capacity fading. In such case, phosphorus doped porous carbon spheres (P–C) material are designed and applied as both sulfur host material and separator modifier to mitigate the shuttling problem in Li–S batteries. The porous structure can physically intake polysulfides, and the same time, the phosphorus element can chemically interact with polysulfides. Based on the favourable combination of both physical adsorption and chemical anchoring, the assembled battery with as-prepared P–C materials acting as both sulfur host and separator modifier can achieve high utilization of active species and realize good cycling stability. Specifically, an initial capacity of 1430 mAh g−1 at 0.1 C and 650 mAh g−1 at 5 C is achieved, with outstanding cyclability and negligible capacity fading rate of 0.06% per cycle at 2 C even for 1000 cycles. Image 1 [ABSTRACT FROM AUTHOR]

Graphite sheets have been synthesized by using hexachlorobutadiene (C4Cl6) and Na as reactants at 500 °C in an autoclave. Transmission electron microscopy images show that the average dimension of graphite sheets is about 8 × 15 μm and the thickness ranges 20–50 nm. The possible reaction mechanism is discussed. [Copyright &y& Elsevier]

Carbon nanotubes were synthesized via a novel route using an iron catalyst at the extremely low temperature of 180 °C. In this process, carbon suboxide was used as carbon source, which changed to freshly formed free carbon clusters through disproportionation. The carbon clusters can grow into nanotubes in the presence of Fe catalyst, which was obtained by the decomposition of iron carbonyl Fe2(CO)9 at 250 °C under nitrogen atmosphere. The products were characterized with XRD, TEM, HRTEM and Raman spectroscopy. [Copyright &y& Elsevier]