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Hard carbons are so far the most promising anode materials of sodium ion batteries, and fabricating hard carbons with various biomasses have been the research focus of many studies. In this work, instead of edible starch, longan kernel that is rich of starch is used as the precursor of hard carbon anodes. Taking advantage of the spherical morphology of starch in longan kernel, spherical hard carbons with low specific surface area and high closed micropore volume are prepared by optimizing the low-temperature pre-oxidation crosslinking conditions. In Na-ion half cells, the optimized hard carbon anode exhibits a high reversible capacity of 385 mAh g−1at 20 mA g−1and excellent rate capability (256 mAh g−1at 2000 mA g−1), which are higher than those of most edible starch-derived hard carbon anodes reported previously. Moreover, when the prepared hard carbon anode is paired with Na3V2(PO4)3cathode, the assembled Na-ion full cells preserve 83 % of its starting capacity after 500 cycles at 200 m A g−1, demonstrating a high prospect for practical applications.

[Display omitted] • N, O co-doped mesoporous carbon spheres were prepared MnO 2 -templated PPy. • The N, O co-doped carbon spheres exhibited outstanding Na storage performance. • N, O co-doping enhanced the rate capability and cycle stability of the carbon anode. • The SIC delivered a high energy density of 103.1 Wh kg−1 at 205.6 W kg−1. The poor rate capability of battery-type anode is usually the bottleneck of the power-energy outputs of a hybrid alkaline metal ion capacitor. In this work, nitrogen and oxygen co-doped mesoporous carbon spheres with excellent rate performance and cycle stability are used as anode materials of sodium ion capacitors (SICs). The high N and O element doping levels as well as the amorphous and mesoporous structure have enabled prominent capacitive Na ion storage behavior, which in turn match well with the capacitive cathode in the hybrid device. Under optimum conditions, the SIC delivers a high energy density of 103.1 Wh kg−1 at a power density of 205.6 W kg−1. Even at a high power density of 7520 W kg−1, an energy density of 23.5 Wh kg−1 is still maintained. Moreover, a robust cycle stability with capacity retention of 84.6 % after 2500 cycles at 1 A g-1 is maintained. Such excellent electrochemical performances convincingly demonstrate that the all-carbon based SICs with the highly capacitive N and O co-doped mesoporous carbon anode can be promising Na ion-based energy storage devices alternative to their Li ion-based counterparts. [ABSTRACT FROM AUTHOR]

The scalable application of SiO anode in lithium ion batteries is still limited by its low initial Coulombic efficiency and inferior cycle stability. Compositing SiO with other substances that own high structural stability, fast Li ion diffusion rate and good Li ion storage capacity has been proven of effectiveness to tackle the aforementioned problems. Herein, manganese niobate (MnNb2O6) that possesses 3-dimensional Li ion diffusion channels is used to modify SiO anode in conjunction with N-doped carbon coating to improve the Li-ion storage performance. Ex situXRD measurements reveal that the orthorhombic MnNb2O6is converted to amorphous LixMnNb2O6during lithiation and reversed back to MnNb2O6in the following delithiation process. The crystal structure of MnNb2O6is well preserved after a long-term cycle test, suggesting its high structural stability. With such stable structure and ultrafast Li ion diffusion kinetics, the optimized SiO@MnNb2O6@NC composite anode exhibits obviously improved rate performance and cycle stability as compared to SiO@NC. A reversible capacity of 835 mAh g−1is maintained at a relatively high current density of 3.0 A g−1, and a discharge capacity of 799 mAh g−1is preserved after 200 cycles at 1.0 A g−1. This work provides a facile and promising strategy to modify SiO-based anode with Columbite-type Nb-based metal oxides towards better Li-ion storage properties.

Silver nanowires (AgNWs)-based transparent electrode is one critical component for many modern electronic devices, however, preparation of high-performance AgNWs-based transparent electrode with appealing light transmittance and long-term stability is still challenging. Herein, by combining the size-optimized AgNWs with graphene oxide (GO), the composite AgNWs/GO film electrode with high light-transmittance and appealing stability is prepared. For the size-controlled preparation of AgNWs, well-defined one-dimensional structure (average diameter = 62 nm) is obtained by elaborately adjusting the Br−concentration (0.05 mM), Cl−concentration (1 mM), ratio of PVP/AgNO3(5:1) and PVP-type selection (PVP1300k: PVP58k= 2:1), contributing to a high light transmittance of 84% for the corresponding AgNWs-based electrode. After further introducing the GO, the film electrode presents much enhanced stability and increased film-substrate adhesive strength, namely only 3.6% increase in resistance after 1000 cycles of bending and being stable even under ultrasonic vibration. The results can provide new insights for designing electrode with ultrastability and high light transmittance.

Commercialization of SiO/graphite (SiO/G) composite anode material has been partially conducted in modern-model Li-ion batteries but is still limited by its relatively high cost and inferior stability. Improving the Li-ion storage performance as well as lowering the manufacturing cost of SiO/G anode has been the ongoing target of many studies. Herein, a low cost SiO/G anode with good Li-ion storage performance is developed by facilely integrating SiO nanoparticles into spent graphite (SG) extracted from used LiFePO4batteries. The loose SG particles after repeated charge/discharge cycles can be easily exfoliated and combined with the SiO nanoparticles during the mechanical ball-milling treatment. Further processing the composite into spherical structure by spray-drying and pyrolysis results in practically applicable anode materials. The SiO/SG/C anode with a SiO mass ratio of 30 % exhibits the best overall performance including an excellent rate capability (385 mAh g−1at 3 A g−1) and encouraging cycle stability (442 mAh g−1after 300 cycles at 1 A g−1). The coin-type full cells coupling the pre-lithiated spherical SiO/SG anode and NCM811 cathode delivers a high energy density of 461 Wh kg−1(based on the active masses of both electrodes) and good cycle performance (74.4 % capacity retention at 0.5C after 100 cycles). This work not only provides a high performance yet low cost SiO/G anode material, but explores a high value added way for the reuse of SG, thus can practically push forward the development of LIBs.

Abstract A composite anode material consisting of a stable inner core of mesocarbon microbeads and a porous nitrogen-doped amorphous carbon shell active for lithium storage is prepared. The thin birnessite MnO 2 nanosheets hydrothermally deposited on mesocarbon microbeads are in situ replaced by polypyrrole, which is then transformed to nitrogen-doped amorphous carbon layer by calcination in nitrogen atmosphere. The surface modified mesocarbon microbeads exhibit average discharge capacities of 444 and 103 mA h g−1 at the current densities of 0.1 and 3 A g−1, respectively, obvious higher than the corresponding values of the bare sample, 371 and 60 mA h g−1. Moreover, the composite anode maintains a discharge capacity of 306 mA h g−1 after 500 cycles at 1 A g−1, suggesting an excellent cycle stability. It is believed that the nitrogen-doped amorphous carbon layer has provided additional lithium storage capacity and stabilized the structure integrity of mesocarbon microbeads. This work demonstrates that the capacity and rate performance of commercial graphitic carbons can be much improved by simply introducing a nitrogen-doped carbon coating layer active for Li storage, making them attractive for high power Li-ion batteries. [ABSTRACT FROM AUTHOR]

Porous LiMn 2 O 4 hollow microspheres were facilely prepared by incorporation of Li and Mn elements into a spherical polymeric precursor through copolymerization of lithium and manganese acetates with resorcinol and hexamethylenetetramine and then burning off the organic matrix at appropriate temperatures in air. The LiMn 2 O 4 inherited the spherical morphology of the polymeric precursor but showed hollow porous structure assembled by nanocrystals of about 50–100 nm in size. When tested as cathode of Li-ion batteries, the LiMn 2 O 4 hollow spheres exhibited excellent rate capability and cycle stability. A discharge capacity of above 90 mAh g −1 was maintained at 10 C (1 C = 120 mA g −1 ), and the cells can still deliver a discharge capacity over 100 mAh g −1 after another 115 cycles at 0.5 C. With such excellent electrochemical properties, the prepared LiMn 2 O 4 hollow microspheres could be promising cathode of Li-ion batteries for long term and high power applications. [ABSTRACT FROM AUTHOR]

Nitrogen and oxygen co-doped micro-foam like mesoporous carbons are prepared from gelatin, an abundant hydrolyzed product of animal collagen with high carbon content and fruitful heteroatoms. Benefiting from the swelled structure of gelatin after pre‑carbonization at 300 °C, the following moderate chemical activation with KOH results in highly mesoporous carbons with specific surface area over 3000 m2g−1and total pore volume larger than 1.96 cm3 g−1while preserving the micro-foam structure. As cathode materials of zinc ion capacitors (ZICs), the carbon micro-foams display very encouraging energy storage performance in both organic and aqueous electrolytes. A high energy density of 90 Wh kg−1is obtained at a power density of 445 W kg−1in 1 M Zn(CF3SO3)2/DMF (N, N-dimethylformamide) electrolyte, whereas in 1 M ZnSO4aqueous electrolyte the ZIC exhibits much better rate capability (54 Wh kg−1at 14650 W kg−1) possibly due to the better wettability and higher ionic conductivity. These excellent electrochemical properties suggest that the N and O co-doped mesoporous carbon micro-foams derived from gelatin can be potential cathode materials of high-performance Zn-ion capacitors.

Enhancing the rate and cycle performance of anode materials is the key in developing high performance Li/Na/K-ion capacitors. Molybdenum selenide (MoSe2) has been well studied as a potential high rate anode material for Na-ion capacitors based on its lamellar structure and large interlayer space. However, the MoSe2anode usually suffers from inferior cycling stability especially when directly exposing to electrolyte. Herein, a composite anode material with MoSe2nanosheets confined in N-doped carbon fibers is prepared by electrospinning and post-selenization process, which exhibits highly capacitive Na ion storage behavior and stable cycle performance in Na-metal half cells. When it is coupled with a pomelo peel-derived porous carbon cathode that is pre-mixed with sodium oxalate as the pre-sodiation additive, the assembled Na-ion capacitors display outstanding energy-power performance, including ultrahigh energy densities of 116 and 79 Wh kg−1achieved at 197 and 8318 W kg−1, respectively, and a quite good stability in a long term cycle test. These results convincingly demonstrate that the composite with MoSe2nanosheets confined in N-doped carbon fibers can be promising high capacitive and stable anode material for high performance Na-ion capacitors.

•Highly porous carbons were produced from sunflower seed hull by ZnCl2activation.•The SSH-derived porous carbons exhibited high yield and controllable pore size.•The SSH-derived porous carbons were efficient Cr(VI) adsorbents.•The optimum pH for Cr(VI) adsorption varied with initial Cr(VI) concentration.

AuCl3 loaded structured catalysts were prepared on SiC foam supported with pre-coated activated carbon layers. The catalytic properties of the structured catalysts towards hydrochlorination of acetylene were tested in a fixed-bed reactor with the AuCl3 loaded on activated carbon pellets as a reference. For isopyknic catalysts, the structured catalyst with only one fifth of the Au amount as that was used on the reference catalyst exhibited even a little higher acetylene conversion and much better stability than the latter no matter what the gas hourly space velocities of acetylene were used. The results indicated that the more homogeneous distribution of AuCl3 particles and better heat transfer along the fixed-bed reactor originated from the low pressure drop and high thermal conductivity of the SiC foam supported structured catalysts might be able to account for their improved efficiency and stability. It is believed that these novel structured C/Au catalysts can be potentially applied in VCM industrialization in view of their greatly reduced cost and much prolonged life. [ABSTRACT FROM AUTHOR]

Different semiconductive SiC foam supports were prepared by varying the sintering temperature and atmosphere, and with or without alkaline solution treatment and high temperature oxidation following a macromolecule pyrogenation combined with reaction bonding method. Nano-TiO2 particles were immobilized onto these SiC foam supports by a composite sol–gel method. The phase, surface morphology, the type of conduction and the photocatalytic activity of the TiO2–SiC composite photocatalysts were studied. The TiO2 coated on p-type Si-free SiC support showed the highest photocatalytic efficiency in degradation of 4-aminobenzenesulfonic acid (4-ABS) in aqueous solution as compared to that coated on n-type SiC support and p-type SiC supports with residual Si or SiO2 on the surface. The result showed that the TiO2 coatings immobilized on p-type semiconductive SiC foam supports exhibited obviously higher photocatalytic activity in comparison to that coated on n-type SiC foam support. The p–n heterojunctions formed between the p-type SiC supports and n-type TiO2 coatings might be able to account for the better charge separation and transfer as well as the photocatalytic activity of the TiO2–SiC composite photocatalyst. [ABSTRACT FROM AUTHOR]

A new kind of open cellular foam material with three dimensionally interconnected TiC/Ti struts was prepared by a two-step sponge-coating and high frequency induction heating process. The microstructure, composition and compression strength of the prepared TiC/Ti foam materials were characterized. It was confirmed that the incorporation of Ti into TiC resulted in an inter-bonded Ti–TiC–Ti layered structure in the struts, which enhanced the plasticity of the composite foam materials. [Copyright &y& Elsevier]

Nanostructured titania have been intensively investigated as anode materials of Li-ion batteries for their excellent high rate performance. The size effects of TiO2 polymorphs (mainly rutile, anatase and TiO2-B) on their electrochemical performance and the latest efforts in nanoengineering titania anodes through enhancing their ionic or electronic transportation or both are reviewed in this work. We suppose that micron- or submicron-sized porous structures assembled by TiO2 nanoparticles, nanowires/nanotubes or nanosheets with a high percentage of exposing high reactive facets together with a conductive percolating network are ideal anodes not only for high rate lithium storage but also for high packing densities of the active materials. [ABSTRACT FROM AUTHOR]

•Highly mesoporous carbons were prepared from corn silks.•High surface area over 2400 m2g-1and pore volume >1.89 cm3g-1were achieved.•A high energy density of 25 Wh kg-1was maintained at 23,070 W kg-1for EDLCs.•A high energy density of 38.5 Wh kg-1was achieved at 14, 741 W kg-1for ZICs.

A remarkably high lithium storage capability, high rate performance, and cyclability were observed in nanometer-sized rutile electrode at room temperature. The Li insertion ratio, , can be well above 1 in rutile nano-electrode at the first discharge cycled at , and about 0.6-0.7 Li can be reversibly cycled. After the discharge capacities of an ultrafine rutile electrode are still of 132 and when being cycled at 5 and , respectively. Our results suggest that nanometer-sized rutile can be a promising anode material for lithium-ion batteries, especially for high power and high energy density use.

We investigated the surface alloying of Au atoms on a Ni (110) surface using a molecular dynamics (MD) method. It is found that the concentration of deposited Au atoms and the depositing temperature determine the topological surface structures, which can be ascribed to the variation in Gibbs free energy of the system. Dimer formation on the over layer is used to explain the surface alloying of the miscible system and in good agreement with the experimental results.

Wurtzite Zinc-gallium oxynitrides (Ga1-xZnxN1-xOx) has attracted a great deal of interest these years as photocatalysts capable of overall water splitting and contamination degradation under visible light irradiation. Ga1-xZnxN1-xOx particles were synthesized by nitridation of Zn/Ga/CO3 layered double hydroxides (LDHs) using a coprecipitation method with constant pH of 8. Single-phase Ga1-xZnxN1-xOx with Zn: Ga mole ratios of 2:1, 3:1, 4:1 and 5:1 were obtained, as characterized by X-ray diffraction and scanning electron microscope. Photocatalytic activities of the obtained particles were evaluated under visible-light irradiation against the photodegradation of methylene blue (MB). The oxynitrde with a Zn:Ga mole ratio of 2:1 showed the highest photoactivity among all the samples.

Here, we report a chemical process for the preparation of nanosized Li4Ti5O12anode material for Li-ion batteries. Anatase TiO2nanopowders were first lithiated in LiOH solution at low temperature and then formed an intermediate Li–Ti–O precursor by oriented attachment, which was subsequently converted to Li4Ti5O12by a short postannealing. The obtained Li4Ti5O12powders were 30 nm in size on average and showed a high phase purity and crystallinity. The electrochemical tests indicated that the synthesized nanosized Li4Ti5O12exhibited a good lithium storage capacity and high cycle stability as well, even at high charge/discharge current rates.

A remarkably high lithium storage capability, high rate performance, and cyclability were observed in nanometer-sized rutile TiO2electrode at room temperature. The Li insertion ratio, Li∕Ti, can be well above 1 in rutile nano-electrode at the first discharge cycled at 0.05A∕g, and about 0.6–0.7 Li can be reversibly cycled. After 100cyclesthe discharge capacities of an ultrafine rutile electrode are still of 132 and 118mAh∕gwhen being cycled at 5 and 10A∕g, respectively. Our results suggest that nanometer-sized rutile can be a promising anode material for lithium-ion batteries, especially for high power and high energy density use.