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Copper is well-known to be selective to primary amines via electrocatalytic nitriles hydrogenation. However, the correlation between the local fine structure and catalytic selectivity is still illusive. Herein, we find that residual lattice oxygen in oxide-derived Cu nanowires (OD-Cu NWs) plays vital roles in boosting the acetonitrile electroreduction efficiency. Especially at high current densities of more than 1.0 A cm−2, OD-Cu NWs exhibit relatively high Faradic efficiency. Meanwhile, a series of advanced in situ characterizations and theoretical calculations uncover that oxygen residues, in the form of Cu4-O configuration, act as electron acceptors to confine the free electron flow on the Cu surface, consequently improving the kinetics of nitriles hydrogenation catalysis. This work could provide new opportunities to further improve the hydrogenation performance of nitriles and beyond, by employing lattice oxygen-mediated electron tuning engineering. While copper is active for electrocatalytic nitriles hydrogenation, the correlation between the local structures and catalytic activity is still illusive. Here, the authors report that residual lattice oxygen in oxide-derived copper nanowires plays vital roles in boosting the hydrogenation activity. [ABSTRACT FROM AUTHOR]

Highlights: Proposing a one-step pyrolysis strategy to fabricate a novel bilayer-shelled N, O-doped hollow porous carbon microspheres (NOHPC) anode. The optimized NOHPC anode displays a high K-storage capacity of 325.9 mAh g−1 at 0.1 A g−1 and excellent rate performance (201.1 mAh g−1 at 5 A g−1 after 6000 cycles). The assembled NOHPC//hollow porous activated carbon microspheres (HPAC) potassium ion hybrid capacitors deliver a high energy density of 90.1 Wh kg−1 at a power density of 939.6 W kg−1 even over 6000 cycles. With the advantages of high energy/power density, long cycling life and low cost, dual-carbon potassium ion hybrid capacitors (PIHCs) have great potential in the field of energy storage. Here, a novel bilayer-shelled N, O-doped hollow porous carbon microspheres (NOHPC) anode has been prepared by a self-template method, which is consisted of a dense thin shell and a hollow porous spherical core. Excitingly, the NOHPC anode possesses a high K-storage capacity of 325.9 mA h g−1 at 0.1 A g−1 and a capacity of 201.1 mAh g−1 at 5 A g−1 after 6000 cycles. In combination with ex situ characterizations and density functional theory calculations, the high reversible capacity has been demonstrated to be attributed to the co-doping of N/O heteroatoms and porous structure improved K+ adsorption and intercalation capabilities, and the stable long-cycling performance originating from the bilayer-shelled hollow porous carbon sphere structure. Meanwhile, the hollow porous activated carbon microspheres (HPAC) cathode with a high specific surface area (1472.65 m2 g−1) deriving from etching NOHPC with KOH, contributing to a high electrochemical adsorption capacity of 71.2 mAh g−1 at 1 A g−1. Notably, the NOHPC//HPAC PIHC delivers a high energy density of 90.1 Wh kg−1 at a power density of 939.6 W kg−1 after 6000 consecutive charge–discharge cycles. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable zinc ion batteries have received widespread attention due to their high energy density and low cost. However, zinc metal anodes face fatal dendrite growth and detrimental side reactions, which affect the cycle stability and practical application of zinc ion batteries. Here, an in-situ formed hierarchical solid-electrolyte interphase composed of InF3, In, and ZnF2 layers with outside-in orientation on the Zn anode (denoted as Zn@InF3) is developed by a sample InF3 coating. The inner ultrathin ZnF2 interface between Zn anode and InF3 layer formed by the spontaneous galvanic replacement reaction between InF3 and Zn, is conductive to achieving uniform Zn deposition and inhibits the growth of Zinc dendrites due to the high electrical resistivity and Zn2+ conductivity. Meanwhile, the middle uniformly generated metallic In and outside InF3 layers functioning as corrosion inhibitor suppressing the side reaction due to the waterproof surfaces, good chemical inactivity, and high hydrogen evolution overpotential. Besides, the as-prepared zinc anode enables dendrite-free Zn plating/stripping for more than 6,000 h at nearly 100% coulombic efficiency (CE). Furthermore, coupled with the MnO2 cathode, the full battery exhibits the long cycle of up to 1,000 cycles with a low negative-to-positive electrode capacity (N/P) ratio of 2.8. [ABSTRACT FROM AUTHOR]

Low discharge capacity and poor cycle stability are the major obstacles hindering the operation of Li-O2 batteries with high-energy-density. These obstacles are mainly caused by the cathode passivation behaviours and the accumulation of by-products. Promoting the discharge process in solution and accelerating the decomposition of discharge products and by-products are able to alleviate above problems to some extent. Herein, chiral salen-Co(II) complex, (1R,2R)-(-)-N,N-bis(3,5-di-t-butylsalicylidene)-1,2-cyclohexanediaminocobalt(II) (Co(II)) as a multi-functional redox mediator was introduced into electrolyte to induce solution phase formation of Li2O2 and catalyze the oxidation of Li2O2 and main by-products Li2CO3. Due to the Co(II) has the solvation effect towards Li+, it can drive solution phase formation of Li2O2, to prevent electrode from passivation and then increase the discharge capacity with a high Li2O2 yield of 96.09 %. Furthermore, the Co(II) possesses suitable redox couple potentials, and it does so while simultaneously boosting the oxidization of Li2O2 and the decomposition of Li2CO3, reducing charge overpotential, and promoting cycle lifespan. Thereby, a cell with Co(II) achieved a long cycling stability at low charge plateau (3.66 V) over 252 cycles with a specific capacity of 500 mAh·gcarbon−1. [ABSTRACT FROM AUTHOR]

Silicon-based materials has attracted attention as a promising candidate for lithium-ion batteries (LIBs) with high energy density. However, severe volume variation, pulverization, and poor conductivity hindered the development of Si based materials. In this study, porous Si microparticles supported by carbon nanotubes (p-Si/CNT) are fabricated through simple molten salt assisted dealloying process at low temperature followed by acid treatment. The ZnCl2 molten salt not only provides the liquid environment to enhance the reaction, but also participates the dealloying process and works as template for porous structure when removes by acid treatment. Additionally, distribution of defect sites in CNTs also increases after molten salt process. Density function theory (DFT) calculations further prove the defects could improve the adsorption of Li+. The participation of CNTs can also contribute to the reaction kinetics and retain the integrity of the electrode. As expected, the p-Si/CNT anode manifests enhanced lithium-storage performance in terms of superior cycling stability and good rate capability. The p-Si/CNT//LiCoO2 full cell assembly further demonstrates its potential as a prospective anode for high-performance LIBs. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable sodium ion batteries (ARSIBs), with intrinsic safety, low cost, and greenness, are attracting more and more attentions for large scale energy storage application. However, the low energy density hampers their practical application. Here, a battery architecture designed by bipolar electrode with graphite/amorphous carbon film as current collector shows high energy density and excellent rate-capability. The bipolar electrode architecture is designed to not only improve energy density of practical battery by minimizing inactive ingredient, such as tabs and cases, but also guarantee high rate-capability through a short electron transport distance in the through-plane direction instead of in-plane direction for traditional cell architecture. As a proof of concept, a prototype pouch cell of 8 V based on six Na2MnFe(CN)6∥NaTi2(PO4)3 bipolar electrodes stacking using a "water-in-polymer" gel electrolyte is demonstrated to cycle up to 4,000 times, with a high energy density of 86 Wh·kg−1 based on total mass of both cathode and anode. This result opens a new avenue to develop advance high-energy ARSIBs for grid-scale energy storage applications. [ABSTRACT FROM AUTHOR]

Sulfur-host material with abundant pore structure and high catalysis plays an important role in development of high-energy-density lithium—sulfur (Li—S) batteries. Herein, we implanted NiCoP nanoparticles into the N,S co-doped porous carbon derived from petroleum coke (PCPC) to fabricate the sulfur-host of PCPC/NiCoP composites. The high specific surface area of PCPC provides abundant adsorption sites for capturing LiPSs and the NiCoP nanoparticles to improve the polarity and boost the LiPSs conversion kinetics of PCPC. The Li—S cells fabricated with PCPC/NiCoP as sulfur-host deliver high discharge capacity of 1,462.7 mAh·g−1 under the current density of 0.1 C and exhibit ultralong lifespan over 800 cycles under the current density of 1, 2, and even 5 C. Additionally, the prepared composites cathodes deliver an outstanding discharge capacity of 932.5 and 826.4 mAh·g−1 at 0.5 and 1 C with a high sulfur loading of over 3.90 mg·cm−2, and remain stable about 60 cycles. Furthermore, the promoted adsorption-conversion process of polysulfides by introducing NiCoP nanoparticles into PCPC was investigated by experimental and theoretical calculation studies. This work offers a new light for tacking the obstacles of porous carbon-based sulfur-host and propelling the development of petroleum coke-based porous carbon for high performance Li—S batteries. [ABSTRACT FROM AUTHOR]

The low initial Coulombic efficiency (ICE) of SiOx anode caused by the irreversible generation of LiySiOz and Li2O during lithiation process limits its application for high energy-density lithium-ion batteries. Herein, we report a molten-salt-induced thermochemical prelithiation strategy for regulating the electrochemically active Si/O ratio of SiOx and thus enhancing ICE through thermal treatment of pre-synthesized LiNH2-coated SiOx in molten LiCl at 700 °C. Bulk SiOx micro-particle was transformed into pomegranate-like prelithiated micro-cluster composite (M-Li-SiOx) with SiOx core and outer nano-sized agglomerates consisting of Li2Si2O5, SiO2, and Si. Through the analysis of the reaction intermediates, molten-LiCl could initiate reactions and promote mass transfer by the continuous extraction of oxygen component from SiOx particle inner in the form of inert Li2Si2O5 and SiO2 nanotubes to realize the prelithiation. The degree of prelithiation can be regulated by adjusting the coating amount of LiNH2 layer, and the resulted M-Li-SiOx displays a prominent improvement of ICE from 58.73% to 88.2%. The graphite/M-Li-SiOx (8:2) composite electrode delivers a discharge capacity of 497.29 mAh·g−1 with an ICE of 91.79%. By pairing graphite/M-Li-SiOx anode and LiFePO4 cathode in a full-cell, an enhancement of energy density of 37.25% is realized compared with the full-cell containing graphite/SiOx anode. Furthermore, ex-situ X-ray photoelectron spectroscopy (XPS)/Raman/X-ray diffraction (XRD) and related electrochemical measurements reveal the SiOx core and Si of M-Li-SiOx participate in the lithiation, and pre-generated Li2Si2O5 with Li+ diffusivity and pomegranate-like structure reduces the reaction resistance and interface impedance of the solid electrolyte interphase (SEI) film. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) have been considered as attractive alternatives for next-generation battery systems, which have promising application potential due to their earth abundance of potassium and sodium, high capacity and suitable working potential, however, the design and application of bi-functional high-performance anode still remain a great challenge up to date. Bismuth sulfide is suitable as anode owing to its unique laminar structure with relatively large interlayer distance to accommodate larger radius ions, high theoretical capacity and high volumetric capacity etc. In this study, dandelion-like Bi2S3/rGO hierarchical microspheres as anode material for PIBs displayed reversible capacity, and 206.91 mAh·g−1 could be remained after 1,200 cycles at a current density of 100 mA·g−1. When applied as anode materials for SIBs, 300 mAh·g−1 could be retained after 300 cycles at 2 A·g−1 and its initial Coulombic efficiency is as high as 97.43%. Even at high current density of 10 A·g−1, 120.3 mAh·g−1 could be preserved after 3,400 cycles. The Na3V2(PO4)3@rGO//Bi2S3/rGO sodium ion full cells were successfully assembled which displays stable performance after 60 cycles at 100 mA·g−1. The above results demonstrate that Bi2S3/rGO has application potential as high performance bi-functional anode for PIBs and SIBs. [ABSTRACT FROM AUTHOR]

Potassium-ion batteries (PIBs) are promising candidates for next-generation energy storage devices due to the earth abundance of potassium, low cost, and stable redox potentials. However, the lack of promising high-performance electrode materials for the intercalation/deintercalation of large potassium ions is a major challenge up to date. Herein, we report a novel uniform nickel selenide nanoparticles encapsulated in nitrogen-doped carbon (defined as "NiSe@NC") as an anode for PIBs, which exhibits superior rate performance and cyclic stability. Benefiting from the unique hierarchical core—shell like nanostructure, the intrinsic properties of metal—selenium bonds, synergetic effect of different components, and a remarkable pseudocapacitance effect, the anode exhibits a very high reversible capacity of 438 mA·h·g−1 at 50 mA·g−1, an excellent rate capability, and remarkable cycling performance over 2,000 cycles. The electrochemical mechanism were investigated by the in-situ X-ray diffraction, ex-situ high-resolution transmission electron microscopy, selected area electron diffraction, and first principle calculations. In addition, NiSe@NC anode also shows high reversible capacity of 512 mA·h·g−1 at 100 mA·g−1 with 84% initial Coulombic efficiency, remarkable rate performance, and excellent cycling life for sodium ion batteries. We believe the proposed simple approach will pave a new way to synthesize suitable anode materials for secondary ion batteries. [ABSTRACT FROM AUTHOR]

Herein, a two-dimensional (2D) interspace-confined synthetic strategy is developed for producing MoS2-intercalated graphite (G-MoS2) hetero-layers composite through sulfuring the pre-synthesized stage-1 MoCl5-graphite intercalation compound (MoCl5-GIC). The in situ grown MoS2 nanosheets (3–7 layers) are evenly encapsulated in graphite layers with intimate interface thus forming layer-by-layer MoS2-intercalated graphite composite. In this structure, the unique merits of MoS2 and graphite components are integrated, such as high capacity contribution of MoS2 and the flexibility of graphite layers. Besides, the tight interfacial interaction between hetero-layers optimizes the potential of conductive graphite layers as matrix for MoS2. As a result, the G-MoS2 exhibits a high reversible Li+ storage of 344 mAh·g−1 even at 10 A·g−1 and a capacity of 539.9 mAh·g−1 after 1,500 cycles at 5 A·g−1. As for potassium ion battery, G-MoS2 delivers a reversible capacity of 377.0 mAh·g−1 at 0.1 A·g−1 and 141.2 mAh·g−1 even at 2 A·g−1. Detailed experiments and density functional theory calculation demonstrate the existence of hetero-layers enhances the diffusion rates of Li+ and K+. This graphite interspace-confined synthetic methodology would provide new ideas for preparing function-integrated materials in energy storage and conversion, catalysis or other fields. [ABSTRACT FROM AUTHOR]

Ti-based anode materials in sodium ion batteries have attracted extensive interests due to its abundant resources, low toxicity, easy synthesis and long cycle life. However, low Coulombic efficiency and limited specific capacity affect their applications. Here, cubic-phase TiP2O7 is examined as anode materials, using in-situ/ex-situ characterization techniques. It is concluded that the redox reactions of Ti4+/Ti3+ and Ti3+/Ti0 consecutively occur during the discharge/charge processes, both of which are highly reversible. These reactions make the specific capacity of TiP2O7 even higher than the case of TiO2 that only contains a simple anion, O2−. Interestingly, Ti species participate only one of the redox reactions, due to the remarkable difference in local structures related to the sodiation process. The stable discharge/charge products in TiP2O7 reduce the side reactions and improve the Coulombic efficiency as compared to TiO2. These features make it a promising Ti-based anode for sodium ion batteries. Therefore, TiP2O7@C microflowers exhibit excellent electrochemical performances, ~ 109 mAh·g−1 after 10,000 cycles at 2 A·g−1, or 95.2 mAh·g−1 at 10 A·g−1. The results demonstrate new opportunities for advanced Ti-based anodes in sodium ion batteries. [ABSTRACT FROM AUTHOR]

Rationally designing sulfur hosts with the functions of confining lithium polysulfides (LiPSs) and promoting sulfur reaction kinetics is critically important to the real implementation of lithium-sulfur (Li-S) batteries. Herein, the defect-rich carbon black (CB) as sulfur host was successfully constructed through a rationally regulated defect engineering. Thus-obtained defect-rich CB can act as an active electrocatalyst to enable the sulfur redox reaction kinetics, which could be regarded as effective inhibitor to alleviate the LiPS shuttle. As expected, the cathode consisting of sulfur and defect-rich CB presents a high rate capacity of 783.8 mA·h·g−1 at 4 C and a low capacity decay of only 0.07% per cycle at 2 C over 500 cycles, showing favorable electrochemical performances. The strategy in this investigation paves a promising way to the design of active electrocatalysts for realizing commercially viable Li-S batteries. [ABSTRACT FROM AUTHOR]

The interstitial structure and weak Ni-N interaction of Ni3N lead to high unoccupied d orbital energy and unsuitable orbital orientation, which consequently results in weak orbital coupling with H2O and slow water dissociation kinetics for alkaline hydrogen evolution catalysis. Herein, we successfully lower the unoccupied d orbital energy of Ni3N to strengthen the interfacial electronic coupling by employing the strong electron pulling capability of oxygen dopants. The prepared O-Ni3N catalyst delivers an overpotential of 55 mV at 10 mA cm−2, very close to the commercial Pt/C. Refined structural characterization indicates the oxygen incorporation can decrease the electron densities around the Ni sites. Moreover, density functional theory calculation further proves the oxygen incorporation can create more unoccupied orbitals with lower energy and superior orientation for water adsorption and dissociation. The concept of orbital-regulated interfacial electronic coupling could offer a unique approach for the rational design of hydrogen evolution catalysts and beyond. [ABSTRACT FROM AUTHOR]

Carbon-coated mesoporous Co9S8 nanoparticles supported on reduced graphene oxide (rGO) are successfully synthesized by a simple process. This composite makes full use of the protection of the carbon layer on the surface, the good conductivity and three-dimensional (3D) structure of rGO, the mesoporous structure and nanoscale size of Co9S8, thereby presenting the excellent electrochemical performances in potassium-ion batteries, 407.9 mAh·g−1 after 100 cycles at 0.2 A·g−1 and 215.1 mAh·g−1 at 5 A·g−1 in rate performances. After 1,200 cycles at 1.0 A·g−1, this composite still remains a capacity of 210.8 mAh·g−1. The redox reactions for potassium storage are revealed by ex-situ transmission electron microscope (TEM)/high-resolution TEM (HRTEM) images, selected area electron diffraction (SAED) patterns and X-ray photoelectron spectroscopy (XPS) spectra. The application of this composite as the host of sulfur for Li-S batteries is also explored. It sustains a capacity of 431.8 mAh·g−1 after 800 cycles at 3 C, leading to a degradation of 0.052% per cycle. These results confirm the wide applications of this composite for electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Hollow spheres of Co0.85Se constructed by two-dimensional (2D) mesoporous ultrathin nanosheets were synthesized via simple and cost effective approach. Their bifunctional electrocatalytic-supercapacitive properties were obtained simultaneously due to synergistic effects between macroscopic morphological features and microscopic atomic/electronic structure of Co0.85Se. The as-synthesized hollow spheres of Co0.85Se that are constructed by 2D mesoporous ultrathin nanosheets exhibit inspiring electrochemical performance for supercapacitor, presenting maximum energy density at high power density (54.66 Wh·kg−1 at 1.6 kW·kg−1) and long cycle stability (88% retention after 8,000 cycles). At the same time, the hollow spheres of Co0.85Se constructed by 2D mesoporous ultrathin nanosheets display excellent catalytic performance for oxygen evolution reaction (OER) due to special structure, high surface area and mesoporous nature of sheets, which achieve low overpotential (290 mV at 10 mA·g−1) and low Tafel slope (81 mV·dec−1) for long-term operation (only 7.8% decay in current density after 9 h). It could be envisioned that the proposed simple approach will pave a new way to synthesize other metal chalcogenides for energy conversion and storage technology. [ABSTRACT FROM AUTHOR]

Crystalline Ge is a highly active anode material for Li storage but inactive for Na storage because of high diffusion barrier. By in-situ Raman spectrum, we explore that the Na could reversibly alloy/dealloy with the amorphous Ge, but does not with the crystalline Ge. Herein, the amorphous Ge is fabricated by an acid-etching Zintl phase Mg2Ge route at room temperature, which shows a mesoporous architecture with a Brunauer–Emmett–Teller (BET) surface area of 29.9 m2·g−1 and a Barrett–Joyner–Halenda (BJH) average pore diameter of 7.6 nm. This mesoporous architecture would enhance the Na-ion/electron diffusion rate and buffer the volume expansion. As a result, the as-prepared amorphous Ge shows superior Na-ion storage performance including high reversible capacity over 550 mA·h·g−1 at 0.2 C after 50 cycles, good rate capability with a capacity of 273 mA·h·g−1 maintained at 5.0 C, and long-term cycling stability with capacities of 450 mA·h·g−1 at 0.4 C after 200 cycles. For the K-ion storage, the amorphous Ge is also more active than the crystalline counter and maintains a capacity of 210 mA·h·g−1 after 100 cycles at 0.2 C. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) battery as one of the most attractive candidates for energy storage systems has attracted extensive interests. Herein, for the first time, hierarchical flower-like cobalt phosphosulfide architectures (defined as "CoSP") derived from Prussian blue analogue (PBA) was fabricated through the conversion of Co-based PBA in PxSy atmosphere. The as-prepared polar CoSP could effectively trap polysulfides through the formation of strong chemical bonds. In addition, after the combination of CoSP with high conductive rGO, the obtained CoSP/rGO as sulfur host material exhibits ultralow capacity decay rate of 0.046% per cycle over 900 cycles at a current density of 1 C. The excellent performance could be attributed to the shortened lithium diffusion pathways, fastened electron transport ability during polysulfide conversion, and increased much more anchor active sites to polysulfides, which is expected to be a promising material for Li-S batteries. It is believed that the as-prepared CoSP/rGO architectures will shed light on the development of novel promising materials for Li-S batteries with high cycle stability. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials have attracted enormous attention due to their functional applications in energy storage. In this work, a low-temperature molten-salt chemical exfoliation methodology is developed for producing free-standing 2D mesoporous Si through deintercalation of CaSi2 in excess molten AlCl3 at 195 °C. The average dimension of these sheets is 1.5 μm, and the thickness of a single sheet is approximately 10 nm. The as-prepared 2D Si has a Brunauer-Emmett-Teller surface area of 154 m2·g−1 and an average pore size of 5.87 nm. With this unique structure, the 2D Si exhibits superior Li-storage performance, including a reversible capacity of 2,974 mA·h·g−1 at 0.2 C, reversible capacities of 2,162, 1,947, and 1,527 mA·h·g−1 at 0.8, 2, and 5 C after 200 cycles, and a capacity retention of 357 mA·h·g−1 even at 30 C (90 A·g−1). [ABSTRACT FROM AUTHOR]

High-capacity anode materials are highly desirable for sodium ion batteries. Here, a porous Sb/SbO nanocomposite is successfully synthesized by the mild oxidization of Sb nanocrystals in air. In the composite, Sb contributes good conductivity and SbO improves cycling stability, particularly within the voltage window of 0.02-1.5 V. It remains at a reversible capacity of 540 mAh·g after 180 cycles at 0.66 A·g. Even at 10 A·g, the reversible capacity is still preserved at 412 mAh·g, equivalent to 71.6% of that at 0.066 A·g. These results are much better than Sb nanocrystals with a similar size and structure. Expanding the voltage window to 0.02-2.5 V includes the conversion reaction between SbO and Sb into the discharge/charge profiles. This would induce a large volume change and high structure strain/stress, deteriorating the cycling stability. The identification of a proper voltage window for Sb/SbO paves the way for its development in sodium ion batteries. [ABSTRACT FROM AUTHOR]

Tin dioxide (SnO) aggregation nanostructures with uniform pores were synthesized through a gas-liquid interfacial reaction driven by solvothermal means. The aggregated particle sizes of this structure can be rationally controlled via adjusting the volume ratios of ethylene glycol and distilled water. Investigation reveals that the more the water was in the mixed solvent the bigger the particles formed in the same reaction time duration, but with the porous distribution unchanged, which may be attributed to the coordination between F and Sn to orderly adjust the hydrolysis rate of Sn. This architecture exhibits excellent cycling stability as an electrode for supercapacitors (97 % capacity retention over 1000 cycles at 1 A g after the first 80 cycles decay). [ABSTRACT FROM AUTHOR]

There have been few reports concerning the hydrothermal synthesis of silicon anode materials. In this manuscript, starting from the very cheap silica sol, we hydrothermally prepared porous silicon nanospheres in an autoclave at 180 °C. As anode materials for lithium-ion batteries (LIBs), the as-prepared nano-silicon anode without any carbon coating delivers a high reversible specific capacity of 2,650 mAh·g at 0.36 A·g and a significant cycling stability of about 950 mAh·g at 3.6 A·g during 500 cycles. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Urchin-like Sn-ZnO-C composite have been successfully prepared by thermal annealing of ZnSn(OH) precursor in acetylene/argon gas (1/9; v/v). The phase of the urchin-like Sn-ZnO-C has been characterized by X-ray diffraction (XRD) and Raman spectrum. The images of scanning electron microscopy (SEM) and transmission electron microscope (TEM) demonstrate that the Sn-ZnO-C composite with an average of 3 μm in diameter is composed of many core-shell nanowires and carbon nanotubes emanated from the center. The thermal annealing temperature and time have crucial effects on the formation of urchin-like structure and carbon content of the Sn-ZnO-C composites. As an anode for lithium-ion batteries, the urchin-like Sn-ZnO-C composite delivers a discharge capacity of 1,034.5 mAh/g in initial cycle and 571.9 mAh/g reversible discharge capacity after 25 cycles at a current density of 50 mA/g. The superior energy storage properties highlight the urchin-like Sn-ZnO-C composite as a potential alternative anode material in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Binary transition metal oxides are considered as promising anode materials for lithium-ion batteries (LIB), because they can effectively overcome the drawbacks of simple oxides. Here, a one-step hydrothermal method is described for the synthesis of regular ZnFeO octahedrons about 200 nm in size at a low temperature without further annealing being required. The ZnFeO octahedrons were characterized by powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The electrochemical performance of the ZnFeO octahedrons was examined in terms of cyclic voltammetry and discharge/charge profiles. The ZnFeO octahedrons exhibit a high capacity of 910 mA·h/g at 60 mA/g between 0.01 and 3.0 V after 80 cycles. They also deliver a reversible specific capacity of 730 mA·h/g even after 300 cycles at 1000 mA/g, a much better performance than those in previous reports. A set of reactions involved in the discharge/charge processes are proposed on the basis of ex situ high-resolution transmission electron microscopy (HRTEM) images and selected area electron diffraction (SAED) patterns of the electrode materials. The insights obtained will be of benefit in the design of future anode materials for lithium ion batteries. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

High purity FeO/helical carbon nanofiber composites were obtained on a large scale by the catalytic pyrolysis of ferrocene in the presence of tin powder at 500°C over 12 h. The sizes of FeO nanoparticles are 35-65 nm in size, and the diameters of the helical carbon nanofibers range from 40-70 nm. The shapes and compositions of the nanocomposites are simply controlled by adjusting the reaction temperatures. On the basis of the obtained experimental results the formation of the helical FeO/carbon nanofiber composites was investigated and discussed. The magnetic hysteresis loop of the products shows ferromagnetic behavior with saturation magnetization ( M), remanent magnetization ( M) and coercivity ( H) values of ca. 29.8 emu/g, 9.6 emu/g and 306.6 Oe, respectively. [ABSTRACT FROM AUTHOR]

We report a new morphology of wurzite cadmium sulfide with nanoparticles decorated on rod-bundle structures, which were synthesized via calcinations of an inorganic/organic composite at 400 °C in air. The composite was hydrothermally synthesized at 180 °C using thioglycolic acid (TGA) and cadmium acetate as starting materials. The structure, composition, and morphology of the prepared material were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope, FT-IR spectrometry, photoluminescence spectrometry, and UV-visible spectrometry. Results indicated that the composite could be defined as CdS /Cd-TGA. X-ray diffraction revealed that the annealed product is CdS with wurtizite phase. The diameter of the rod is about 150-400 nm and the length from the top to the bottom of the decorated nanoparticle is about 100 nm. The composite showed high intensity of photoluminescence with similar peak position, compared to that of wurtzite CdS, because of the structure defects. [ABSTRACT FROM AUTHOR]

This paper reviews the solution-phase synthesis of nanoparticles via some routes at low temperatures, such as room temperature route, wave-assisted synthesis (γ-irradiation route and sonochemical route), directly heating at low temperatures, and hydrothermal/solvothermal methods. A number of strategies were developed to control the shape, the size, as well as the dispersion of nanostructures. Using diethylamine or n-butylamine as solvent, semiconductor nanorods were yielded. By the hydrothermal treatment of amorphous colloids, Bi2S3 nanorods and Se nanowires were obtained. CdS nanowires were prepared in the presence of polyacrylamide. ZnS nanowires were obtained using liquid crystal. The polymer poly (vinyl acetate) tubule acted as both nanoreactor and template for the CdSe nanowire growth. Assisted by the surfactant of sodium dodecyl benzenesulfonate (SDBS), nickel nanobelts were synthesized. In addition, Ag nanowires, Te nanotubes and ZnO nanorod arrays could be prepared without adding any additives or templates. [ABSTRACT FROM AUTHOR]

β-Mn2V2O7 microtubes with a length of 15–25 μm, 2.5–3.5 μm external diameter, and ∼0.4 μm wall thickness, as well as β-Mn2V2O7 hollow microspheres with an average outer diameter of 2 μm, were successfully synthesized in a suitable molar ratio of NH4VO3 and MnCO3 powders via a hydrothermal process. X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM) were used to characterize the products, and the magnetic susceptibility curve was also measured. In the whole process, the concentration of Mn2+ cations derived from MnCO3 dissolution plays a crucial role in the formation of β-Mn2V2O7 microtubes and hollow microspheres. [ABSTRACT FROM AUTHOR]

A single phase of monoclinic MnV2O6 nanoflakes was prepared by a hydrothermal process at 180°C for 18 h, using Mn (CH3COO)2·4H2O and NH4VO3 as starting materials and using acetic acid to adjust the pH value of the reaction solution. The as-prepared samples were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). X-ray photoelectron spectrum (XPS) measurements further confirm the component of MnV2O6. Results indicated that the products consisted of a large quantity of compact accumulated nanoflakes, with average width of 0.85 μm, thickness of 100 nm and lengths up to 1.7 μm. [ABSTRACT FROM AUTHOR]

Molybdenum nitride (MoN) nanoparticles with high BET surface area (SBET = 351.0352 m2/g) have been successfully obtained from ammonium polymolybdate, (NH4)6Mo7O24. Differential thermal analysis (DTA), thermogravimetric analysis (TGA) and X-ray powder diffraction (XRD) analysis were used to investigate the effect of water in the precursor. X-ray photoelectron spectroscopy (XPS) was used to determine the empirical formula of the product. Also, MoN nanorods with high aspect ratio have been prepared using Al2O3 template. XRD, transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) were used to characterize the structure of the nanorods. [ABSTRACT FROM AUTHOR]

Graphene-wrapped FeO nanorings (RGO/FeO) were synthesized by a facile approach, which assembled with graphene and the FeO nanorings precursor through the colloidal coagulation effect at room temperature. The uniform FeO nanorings prepared by hydrothermal routes were homogeneously distributed and well wrapped by graphene. When tested as anode for lithium ion batteries, RGO/FeO exhibits a high capacity and good cycling stability. This could be attributed to the interaction of ring-shaped structure and graphene sheets, which inherit the good kinetic property of FeO nanorings and enhance the structural integrity with graphene sheets' support. [ABSTRACT FROM AUTHOR]

Discusses the importance of nanocrystalline nickel in magnetic materials and the development of the ...-radiation method to prepare nanocrystalline materials. How to prepare nanocrystalline nickel powder; Increase of nickel particles and radiation-chemistry yield of nickel in irradiated solutions; Process of reducing Ni2+ ions in solution.

Presents information on nanocrystalline semiconductors, while focusing on its synthesization using the hydrothermal process in the non-aqueous system. Reasons given for the difficulty in the synthesization of nanocrystalline; Preparation of nanocrystalline InP through a non-aqueous thermal process; Detailed information on the process; Information on the experiment; Examination of the results and discussion.

Molybdenum disulfide is naturally inert for alkaline hydrogen evolution catalysis, due to its unfavorable water adsorption and dissociation feature originated from the unsuitable orbital orientation. Herein, we successfully endow molybdenum disulfide with exceptional alkaline hydrogen evolution capability by carbon-induced orbital modulation. The prepared carbon doped molybdenum disulfide displays an unprecedented overpotential of 45 mV at 10 mA cm−2, which is substantially lower than 228 mV of the molybdenum disulfide and also represents the best alkaline hydrogen evolution catalytic activity among the ever-reported molybdenum disulfide catalysts. Fine structural analysis indicates the electronic and coordination structures of molybdenum disulfide have been significantly changed with carbon incorporation. Moreover, theoretical calculation further reveals carbon doping could create empty 2p orbitals perpendicular to the basal plane, enabling energetically favorable water adsorption and dissociation. The concept of orbital modulation could offer a unique approach for the rational design of hydrogen evolution catalysts and beyond. Technologies allowing for sustainable hydrogen production will contribute to the decarbonization of the future energy supply. Here the authors report that carbon induced orbital modulation can facilitate the otherwise inert MoS2 electrocatalyst superior alkaline hydrogen evolution reactivity. [ABSTRACT FROM AUTHOR]

Presents information on solvothermal synthesis of titanium phosphides. Group IV transition metal phosphides have a number of phases with different stoichiometries. Among these, titanium phosphide has a high thermal stability, inertness to chemical attack, high thermal and electrical conductivity, high hardness and strength. In the solvothermal process, nascent phosphorus and titanium were generated by reducing titanium chloride and combined forming titanium phosphides.

Presents information on solvothermal synthesis of titanium phosphides. Group IV transition metal phosphides have a number of phases with different stoichiometries. Among these, titanium phosphide has a high thermal stability, inertness to chemical attack, high thermal and electrical conductivity, high hardness and strength. In the solvothermal process, nascent phosphorus and titanium were generated by reducing titanium chloride and combined forming titanium phosphides.