Search

A novel nanocomposite based on mesoporous single-crystalline TiO 2 particles (TiO 2 mesocages) threaded with carbon nanotubes (CNTs) has been successfully synthesized via a facile solvothermal method. The unique hybrid architecture endows the nanocomposite with facile ion and electron transport pathways, abundant active surface sites and high structure robustness. As a result, remarkable electrochemical lithium storage properties in terms of high capacity, excellent rate capability and ultra-stable long-term cycling performance have been achieved by the CNTs-threaded TiO 2 mesocages.

Sodium-ion capacitors can potentially combine the virtues of high power capability of conventional electrochemical capacitors and high energy density of batteries. However, the lack of high-performance electrode materials has been the major challenge of sodium-based energy storage devices. In this work, we report a microwave-assisted synthesis of single-crystal-like anatase TiO2 mesocages anchored on graphene as a sodium storage material. The architecture of the nanocomposite results in pseudocapacitive charge storage behavior with fast kinetics, high reversibility, and negligible degradation to the micro/nanostructure. The nanocomposite delivers a high capacity of 268 mAh g–1 at 0.2 C, which remains 126 mAh g–1 at 10 C for over 18 000 cycles. Coupling with a carbon-based cathode, a full cell of sodium-ion capacitor successfully demonstrates a high energy density of 64.2 Wh kg–1 at 56.3 W kg–1 and 25.8 Wh kg–1 at 1357 W kg–1, as well as an ultralong lifespan of 10 000 cycles with over 90% of capacity rete...

Commercialization of ZnO-based anodes remains hampered by their rapid capacity fading upon cyclical charge and discharge. Design and synthesis of suitable carbon scaffolds for coating ZnO active materials has been regarded as the most effective strategy to overcome this problem. We herein report a confined growth strategy for the synthesis of a novel ZnO/carbon mesoporous composite that consists of small ZnO nanoparticles whose growth is confined in rationally designed N-rich carbon spheres (referred to as ZnO-NMPCS). Such a mesoporous nanocomposite has several structural merits such as small ZnO nanoparticles, a homogeneous distribution, an interconnected spherical framework with a large surface area, and a N-rich carbon lattice; these merits not only provide a robust scaffold for stable lithiation/delithiation of ZnO active materials but also ensure sufficient Li+ storage space/sites and fast ions/electrons transport. As a result, the developed nanocomposite exhibits excellent Li+ storage properties in terms of high capacity, fast rate capability, and long cycling lifespan (425 mAh g−1 after 1800 cycles at 5 A g−1). This work offers an effective confined growth strategy to overcome the long-term roadblock to ZnO-based anodes; the carbon scaffold also provides a general platform for the confined growth of other metal oxide nanocrystals.

Electrochemical water splitting is considered as a promising approach to produce clean and sustainable hydrogen fuel. As a new class of nanomaterials with high ratio of surface atoms and tunable composition and electronic structure, metal clusters are promising candidates as catalysts. Here, a new strategy is demonstrated to synthesize active and stable Pt-based electrocatalysts for hydrogen evolution by confining Pt clusters in hollow mesoporous carbon spheres (Pt5 /HMCS). Such a structure would effectively stabilize the Pt clusters during the ligand removal process, leading to remarkable electrocatalytic performance for hydrogen production in both acidic and alkaline solutions. Particularly, the optimal Pt5 /HMCS electrocatalyst exhibits 12 times the mass activity of Pt in commercial Pt/C catalyst with similar Pt loading. This study exemplifies a simple yet effective approach to improve the cost effectiveness of precious-metal-based catalysts with stabilized metal clusters. NRF (Natl Research Foundation, S’pore) Accepted version

Building nanocomposite architectures based on carbon nanotubes (CNTs) and active nanoparticles (NPs) with an engineered interface is of great interest for developing the ability to store electrochemical energy. The use of cellulose to direct hetero-assembly was achieved by in situ regenerating an ionic liquid mixture (CNTs, NPs, cellulose) in water, and was applied to the fabrication of flexible anodes consisting of CNTs and NPs. These anodes showed CNTs threading through their structures and exhibited strong interfacial contacts, which provided a relatively short lithium-ion diffusion length and continuous electron conduction pathway as well as high mechanical stability. When evaluated as an anode material for a lithium-ion battery, the flexible nanocomposites showed high reversible capacity and good rate performance compared to traditionally made electrodes, demonstrating a simple and green strategy for the industrial-scale production of energy-storage devices.

Aqueous Ni-Fe battery with high safety and low cost is a promising candidate for large-scale electrical energy storage; their performance, however, has been limited by the poor performance of the Fe electrodes. We reported herein a facile synthesis of Fe particles coated with graphitic shell for high-performance Fe anodes. The anodes exhibit a high capacity of 224 mAh g−1 at a high current density of 32 A g−1, and a high capacity retention of 90% after 1000 cycles. When coupled with a cathode made from the composites of Ni(OH)2 and nitrogen-doped graphene, the battery delivers a high energy density of 136.7 Wh kg−1 at power density of 0.7 kW kg−1 or 71.4 Wh kg−1 at 11.7 kW kg−1 (based on the total mass of active materials). This work provides highly promising materials towards better Ni-Fe batteries.

Supercapacitors have high power densities, high efficiencies, and long cycling lifetimes; however, to enable their wider use, their energy densities must be significantly improved. The design and synthesis of improved carbon materials with better capacitance, rate performance, and cycling stability has emerged as the main theme of supercapacitor research. Herein, we report a facile synthetic method to prepare nitrogen-rich carbon particles based on a continuous aerosol-spraying process. The method yields particles that have high surface areas, a uniform microporous structure, and are highly N-doped, resulting in a synergism that enables the construction of supercapacitors with high energy and power density for use in both aqueous and commercial organic electrolytes. Furthermore, we have used density functional theory calculations to show that the improved performance is due to the enhanced wettability and ion adsorption interactions at the carbon/electrolyte interface that result from nitrogen doping. These findings provide new insights into the role of heteroatom doping in the capacitance enhancement of carbon materials; in addition, our method offers an efficient route for large-scale production of doped carbon.

Fluorine-rich nanoporous carbons with tunable porosity and F content have been successfully synthesized from a silane precursor using a solution-based F doping method. The F-rich carbon surface with higher polarity provides stronger affinity and wettability for the organic electrolyte, which is for the first time demonstrated though Gauss computational calculation between F-carbon surface and organic electrolytes. The optimized F-rich nanoporous carbon manifests a high specific capacitance of 168 F g −1 in a symmetric cell with excellent retention at high rates and upon prolonged 10,000 cycles.

NiFe layered double hydroxides (LDHs) have been intensively investigated as promising electrocatalysts for oxygen evolution reaction. However, their hydrogen evolution reaction (HER) and overall water splitting performance are not satisfactory. Herein, we report a facile cation doping combined with plasma reduction strategy to generate heterostructured Ni nanoparticles/V-doped NiFe LDH nanosheet array with multiple vacancies, exhibiting excellent HER performance with a small overpotential of 19 mV at 10 mA cm−2. Moreover, when evaluated as bi-functional electrocatalyst for overall water splitting, a small cell voltage (1.43 V at 10 mA cm−2) and ultralong stability (over 1000 h) are achieved. Density functional theory (DFT) calculations reveal that V-doping, oxygen vacancy (Ov), Ni vacancy (Niv), and Ni nanoparticles can effectively improve the conductivity and optimize the hydrogen adsorption, Ov, Niv, and Ni nanoparticles help to facilitate H2O adsorption and dissociation progress in HER, the V-doping and Ov can efficiently reduce the energy barrier of O* in OER, and Ni/NiFe LDH heterostructure ameliorates the electronic structure and tunes electron transfer route.

Proton exchange membrane fuel cells have been regarded as the most promising candidate for fuel cell vehicles and tools. Their broader adaption, however, has been impeded by cost and lifetime. By integrating a thin layer of tungsten oxide within the anode, which serves as a rapid-response hydrogen reservoir, oxygen scavenger, sensor for power demand, and regulator for hydrogen-disassociation reaction, we herein report proton exchange membrane fuel cells with significantly enhanced power performance for transient operation and low humidified conditions, as well as improved durability against adverse operating conditions. Meanwhile, the enhanced power performance minimizes the use of auxiliary energy-storage systems and reduces costs. Scale fabrication of such devices can be readily achieved based on the current fabrication techniques with negligible extra expense. This work provides proton exchange membrane fuel cells with enhanced power performance, improved durability, prolonged lifetime, and reduced cost for automotive and other applications., Proton exchange membrane fuel cells often suffer from low lifetimes and high cost. Here, the authors enhance the transient power performance and durability of these fuel cells by integrating a thin layer of tungsten oxide within the anode, which acts as a hydrogen reservoir, oxygen scavenger, and a regulator for the hydrogen-disassociation reaction.

A low-cost and scalable method has been developed to synthesize Fe-decorated N-rich carbon electrocatalysts for the oxygen reduction reaction (ORR) based on pyrolysis of metal carbonyls containing metal–organic frameworks (MOFs). Such a method simultaneously optimizes the Fe-related active sites and the porous structure of the catalysts. Accordingly, the best-performing Fe-NC-900-M catalyst shows excellent ORR activity with a half-wave potential of 0.91 V vs. RHE, exceeding that of the 40% Pt/C catalyst in alkaline media. Furthermore, the zinc–air batteries constructed with Fe-NC-900-M as the cathode catalyst exhibit high open-circuit voltage (1.5 V) and peak power density (271 mW cm−2), and outperform most zinc–air batteries with noble-metal free ORR catalysts.

Transition metal oxides are promising candidates for the high-capacity anode material in lithium-ion batteries. The electrochemical performance of transition metal oxides can be improved by constructing suitable composite architectures. Herein, we demonstrate a metal–organic framework (MOF)-assisted strategy for the synthesis of a hierarchical hybrid nanostructure composed of Fe2O3 nanotubes assembled in Co3O4 host. Starting from MOF composite precursors (Fe-based MOF encapsulated in a Co-based host matrix), a complex structure of Co3O4 host and engulfed Fe2O3 nanotubes was prepared by a simple annealing treatment in air. By virtue of their structural and compositional features, these hierarchical composite particles reveal enhanced lithium storage properties when employed as anodes for lithium-ion batteries. Electronic supplementary material The online version of this article (10.1007/s40820-018-0197-1) contains supplementary material, which is available to authorized users.

Silicon holds great promise as an anode material for lithium-ion batteries with higher energy density; its implication, however, is limited by rapid capacity fading. A catalytic growth of graphene cages on composite particles of magnesium oxide and silicon, which are made by magnesiothermic reduction reaction of silica particles, is reported herein. Catalyzed by the magnesium oxide, graphene cages can be conformally grown onto the composite particles, leading to the formation of hollow graphene-encapsulated Si particles. Such materials exhibit excellent lithium storage properties in terms of high specific capacity, remarkable rate capability (890 mAh g-1 at 5 A g-1 ), and good cycling retention over 200 cycles with consistently high coulombic efficiency at a current density of 1 A g-1 . A full battery test using LiCoO2 as the cathode demonstrates a high energy density of 329 Wh kg-1 .

A simple and scalable melt infiltration method has been developed to encapsulate SnO2 nanocrystals into a hierarchically porous carbon matrix as a high-capacity lithium storage material. SnO2 nanocrystals in a three-dimensional carbonaceous network are obtained via melt infiltration of SnCl2 and subsequent in situ conversion. The SnO2–carbon composite delivers high capacity with a long lifespan of over 800 cycles. Such a method provides an efficient strategy to encapsulate active materials into porous carbons with superior electrochemical performance.

Lithium–sulfur (Li–S) batteries have attracted much attention in the field of electrochemical energy storage and conversion. As a vital part of the cathode electrode, the host materials of sulfur usually have a strong impact on the capacity, energy density, cycle life and Coulombic efficiency of Li–S batteries. With their unique physical and chemical properties, the rationally designed hollow nanostructures show conspicuous advantages as sulfur hosts, and have significantly improved the overall performance of Li–S cells. The scope of this review considers the unique structural advantages of hollow host materials for high-performance Li–S batteries, together with a summary of recent advances in the design and synthesis of various hollow micro-/nanostructures with controlled shapes, tailored shell structures and designed chemical compositions. Finally, we propose some emerging requirements of sulfur hosts which we hope will shed some light on the future development trend of hollow structures for advanced Li–S batteries.

Hollow structures of rutile TiO2 , and especially with non-spherical shape, have rarely been reported. Herein, high-quality rutile TiO2 submicroboxes have been synthesized by a facile templating method using Fe2 O3 submicrocubes as removable templates. Compared to other rutile TiO2 nanomaterials, the as-prepared rutile TiO2 submicroboxes manifest superior lithium storage properties in terms of high specific capacity, long-term cycling stability, and excellent rate capability.

Three-dimensional (3D) Pt-based alloy nanostructures composed of one-dimensional (1D) nanowires/nanorods have recently attracted significant interest as electrocatalysts. In this work, we report an effective solvothermal method for the direct preparation of 3D Pt–Co nanowire assemblies (NWAs) with tunable composition. The composition- and structure-dependent electrocatalytic performance is thoroughly investigated. Because of the bimetallic synergetic effect and unique structural advantage, the as-prepared 3D Pt3Co NWA outperforms commercial Pt/carbon and Pt black catalysts and even 3D Pt NWA. The electrochemical results demonstrate that the 3D Pt3Co NWA is indeed a promising electrocatalyst with enhanced catalytic activity and improved durability for practical electrocatalytic applications.

Functional nanomaterials with three-dimensional hierarchical structures are of high interest for many practical applications including lithium-ion batteries (LIBs). In this work, self-organized sheaf-like Fe3O4/C microrods constructed by porous nanowires have been synthesized by a facile solvothermal method combined with a subsequent annealing treatment. The morphology of the building blocks could be easily tuned by varying the synthesis parameters. When applied as an anode material for LIBs, these sheaf-like Fe3O4/C porous microrods manifest superior electrochemical lithium storage properties in terms of high reversible capacity, stable cycling capacity retention and good rate capability.

Solid-state electrolytes are the key to the development of lithium-based batteries with dramatically improved energy density and safety. Inspired by ionic channels in biological systems, a novel class of pseudo solid-state electrolytes with biomimetic ionic channels is reported herein. This is achieved by complexing the anions of an electrolyte to the open metal sites of metal-organic frameworks (MOFs), which transforms the MOF scaffolds into ionic-channel analogs with lithium-ion conduction and low activation energy. This work suggests the emergence of a new class of pseudo solid-state lithium-ion conducting electrolytes.

Metal-organic frameworks and their derived materials are highly interesting for electrochemical energy storage and conversion., In addition to their conventional uses, metal-organic frameworks (MOFs) have recently emerged as an interesting class of functional materials and precursors of inorganic materials for electrochemical energy storage and conversion technologies. This class of MOF-related materials can be broadly categorized into two groups: pristine MOF-based materials and MOF-derived functional materials. Although the diversity in composition and structure leads to diverse and tunable functionalities of MOF-based materials, it appears that much more effort in this emerging field is devoted to synthesizing MOF-derived materials for electrochemical applications. This is in view of two main drawbacks of MOF-based materials: the low conductivity nature and the stability issue. On the contrary, MOF-derived synthesis strategies have substantial advantages in controlling the composition and structure of MOF-derived materials. From this perspective, we review some emerging applications of both groups of MOF-related materials as electrode materials for rechargeable batteries and electrochemical capacitors, efficient electrocatalysts, and even electrolytes for electrochemical devices. By highlighting the advantages and challenges of each class of materials for different applications, we hope to shed some light on the future development of this highly exciting area.

Sodium-ion capacitors can potentially combine the virtues of high power capability of conventional electrochemical capacitors and high energy density of batteries. However, the lack of high-performance electrode materials has been the major challenge of sodium-based energy storage devices. In this work, we report a microwave-assisted synthesis of single-crystal-like anatase TiO

Lithium–sulfur batteries, notable for high theoretical energy density, environmental benignity, and low cost, hold great potential for next-generation energy storage. Polysulfides, the intermediates generated during cycling, may shuttle between electrodes, compromising the energy density and cycling life. We report herein a class of regenerative polysulfide-scavenging layers (RSL), which effectively immobilize and regenerate polysulfides, especially for electrodes with high sulfur loadings (e.g., 6 mg cm–2). The resulting cells exhibit high gravimetric energy density of 365 Wh kg–1, initial areal capacity of 7.94 mAh cm–2, low self-discharge rate of 2.45% after resting for 3 days, and dramatically prolonged cycling life. Such blocking effects have been thoroughly investigated and correlated with the work functions of the oxides as well as their bond energies with polysulfides. This work offers not only a class of RSL to mitigate shuttling effect but also a quantified design framework for advanced lithium–...

Despite the great advantages of hollow structures as electrodes for lithium-ion batteries, one apparent common drawback which is often criticized is their compromised volumetric energy density due to the introduced hollow interior. Here, we design and synthesize bowl-like SnO2 @carbon hollow particles to reduce the excessive hollow interior space while retaining the general advantages of hollow structures. As a result, the tap density can be increased about 30 %. The as-prepared bowl-like SnO2 @carbon hollow particles with conformal carbon support exhibit excellent lithium storage properties in terms of high capacity, stable cyclability and excellent rate capability.

Hierarchical MoS2 microboxes constructed by ultrathin nanosheets are synthesized by a facile template-assisted strategy. The first step involves the L-cysteine assisted uniform growth of hierarchical MoS2 nanosheets on MnCO3 microcube templates which are at the same time converted to MnS. Hierarchical MoS2 microboxes can be obtained by selectively dissolving MnS through acid washing. When evaluated as an anode material for lithium-ion batteries, the hierarchical MoS2 microboxes manifest high specific capacity and excellent cycling performance. The hierarchical MoS2 microboxes also show enhanced electrocatalytic activity for electrochemical hydrogen evolution from water.

Semiconductor heterostructures are of great interest in a wide range of applications. In this work, we design and synthesize a novel heteronanostructure with controlled relative composition, i.e., BiVO4/Bi2S3 hollow discoid-like particles with mesoporous shell. The synthesis involves a facile anion exchange process by reacting pre-synthesized BiVO4 discoid-like particles with Na2S in an aqueous solution. Benefiting from the unique structural features and the formation of heterostructure, the as-prepared BiVO4/Bi2S3 hollow discoids exhibit significantly enhanced photoelectrochemical current response and photocatalytic activity for reduction of Cr(VI) under visible-light illumination.

Hollow nanostructures are of great interest for a wide variety of applications. Despite the great advances, synthesis of anisotropic hollow structures is still very challenging. In this work, we have developed a simple sacrificial template method to synthesize uniform Ni(x)Co(3-x)S4 hollow nanoprisms with tunable composition. Tetragonal nanoprisms of nickel-cobalt acetate hydroxide precursors with controllable Ni/Co molar ratios are first synthesized and used as the sacrificial templates. After a sulfidation process with thioacetamide (TAA) in ethanol, the solid precursor prisms can be transformed into the corresponding Ni(x)Co(3-x)S4 hollow nanoprisms with a well-defined hollow interior. The intriguing structural and compositional features are beneficial for electrochemical applications. Impressively, the resultant Ni(x)Co(3-x)S4 hollow prisms manifest a high specific capacitance with enhanced cycling stability, making them potential electrode materials for supercapacitors.

CoSe2 is a potential anode material for sodium-ion batteries in terms of their high sodium storage capacity and tunable properties. However, structural degradation and unstable interphase during the reversible sodiation and de-sodiation lead to fast capacity decay. In this work, we develop a nanocomposite architecture based on CoSe2 nanoparticles embedded in N-doped carbon matrix with conformal TiO2 coating (CoSe2@NC@TiO2) by using a metal-organic framework-assisted strategy. The small CoSe2 nanoparticles and N-doped carbon matrix facilitate charge transport and suppress the structural degradation, while the redox-active TiO2 shell further strengthens the structural and interfacial stability without decreasing the capacity. The as-prepared CoSe2@NC@TiO2 nanocomposite particles deliver a reversible sodium storage capacity of 520 mAh g−1 at 0.1 A g−1 with a capacity retention of 78% after 200 cycles, in contrast to the rapid capacity fading after 50 cycles of the pristine CoSe2@NC particles without TiO2 shell.

Seit kurzem findet eine Familie gemischter Ubergangsmetalloxide (mixed transition-metal oxides, MTMOs; beschrieben durch AxB3−xO4; A, B=Co, Ni, Zn, Mn, Fe usw.) mit stochiometrischen oder gar nichtstochiometrischen Zusammensetzungen (typischerweise in Spinellstruktur) weltweit Interesse. Diese MTMOs durften dank ihrer ausgezeichneten elektrochemischen Eigenschaften grose Bedeutung fur kostengunstige und umweltfreundliche Technologien zur Energiespeicherung/-umwandlung erlangen. In diesem Aufsatz fassen wir die jungsten Fortschritte beim rationalen Design von MTMOs mit steuerbaren Formen, Grosen, Zusammensetzungen und Mikro-/Nanostrukturen sowie ihren Anwendungsmoglichkeiten zusammen, z. B. als Elektrodenmaterialien fur Lithium-Ionen-Batterien und elektrochemische Kondensatoren oder als effiziente Elektrokatalysatoren bei der Sauerstoffreduktionsreaktion in Sauerstoff/Luft-Batterien und Brennstoffzellen. Zum Schluss diskutieren wir die weitere mogliche Entwicklung von MTMOs fur die nachste Technologiegeneration der elektrochemischen Energiespeicherung/-umwandlung.

A facile two-step strategy involving a polyol method and subsequent thermal annealing treatment is successfully developed for the general synthesis of metal oxide/carbon coaxial nanocables. Benefitting from the strong coupling effect, these hybrid nanocables exhibit remarkable lithium storage properties with high capacity, long cycle life and excellent rate capability.

Increasing the complexity of hollow structures, in terms of chemical composition and shell architecture, is highly desirable for both fundamental studies and realization of various functionalities. Starting with metal-organic frameworks (MOFs), we demonstrate a general approach toward the large-scale and facile synthesis of complex hollow microboxes via manipulation of the template-engaged reactions between the Prussian blue (PB) template and different alkaline substances. The reaction between PB microcubes with NaOH solution leads to the formation of Fe(OH)3 microboxes with controllable multishelled structure. In addition, PB microcubes will react with the conjugate bases of metal oxide based weak acids, generating multicompositional microboxes (Fe2O3/SnO2, Fe2O3/SiO2, Fe2O3/GeO2, Fe2O3/Al2O3, and Fe2O3/B2O3), which consist of uniformly dispersed oxides/hydroxides of iron and another designed element. Such complex hollow structures and atomically integrated multiple compositions might bring the usual physiochemical properties. As an example, we demonstrate that these complex hollow microboxes, especially the Fe2O3/SnO2 composite microboxes, exhibit remarkable electrochemical performance as anode materials for lithium ion batteries.

In this work, rattle-type ball-in-ball V2O5 hollow microspheres are controllably synthesized with the assistance of carbon colloidal spheres as hard templates. Carbon spheres@vanadium-precursor (CS@V) core–shell composite microspheres are first prepared through a one-step solvothermal method. The composition of solvent for the solvothermal synthesis has great influence on the morphology and structure of the vanadium-precursor shells. V2O5 hollow microspheres with various shell architectures can be obtained after removing the carbon microspheres by calcination in air. Moreover, the interior hollow shell can be tailored by varying the temperature ramping rate and calcination temperature. The rattle-type V2O5 hollow microspheres are evaluated as a cathode material for lithium-ion batteries, which manifest high specific discharge capacity, good cycling stability and rate capability.

As alike as two peas in a pod: Hollow iron-containing microspheres composed of nanoplate-like building blocks were synthesized by a straightforward strategy and readily converted into magnetic Fe3O4 hollow microspheres (see images) without noticeable structural deformation. These Fe3O4 microspheres exhibited high reversible capacity and excellent cycling performance when evaluated as an anode material for lithium-ion batteries.

Owing to their unique structural features, hollow micro-/ nanostructures have aroused intense research interest in a wide range of areas such as energy storage, catalysis, chemical sensors, and biomedical applications. [ 1–10 ] The templating method is considered the most representative and straightforward route to fabricate hollow structures with well-defi ned morphologies and high uniformity. [ 11 ] This versatile method generally involves the growth of a shell of designed materials against various templates (e.g., monodisperse colloidal polymer/silica spheres) to form a core–shell structure, and the subsequent removal of the interior materials, which conceptually facilitates the manipulation of the size, shape, and local chemical environment of the resultant hollow structures. [ 2 , 12 , 13 ] Nevertheless, practically, templating methods face quite a few challenges, such as the diffi culty to achieve uniform coating due to compatibility issues between the template and desired shell materials. [ 14 ] Moreover, removal of the interior templates, which is usually through tedious etching/calcination treatments and likely causes collapse and deformation of the exterior shell, holds another key to obtain well-defi ned hollow structures. Very recently, a few works have reported the syntheses of hollow structures by modifi ed templating strategies, which simultaneously realize the functionalization of the exterior shell and the elimination of the internal template. Zhao and coworkers reported the fabrication of Fe 3 O 4 @titanate yolk–shell microspheres from TiO 2 @SiO 2 @ Fe 3 O 4 core–shell structures. [ 15 ] The outmost TiO 2 shell was converted into titanate nanosheets during the removal of the SiO 2 layer through a facile hydrothermal approach in a NaOH solution. Our group has previously reported the synthesis of NiS hollow spheres from SiO 2 @nickel silicate core–shell structures by a one-step hydrothermal reaction in a Na 2 S solution, during which the sulfi dation of nickel silicate and dissolution of silica take place at the same time. [ 16 ] However, such modifi ed templating strategies have not been widely practiced yet. Spinel Li 4 Ti 5 O 12 has been extensively investigated as one of the most promising anode materials for high-rate lithium-ion batteries (LIBs) because of the zero volume change during lithiation and improved safety in operation. [ 17–19 ] Typically, Li 4 Ti 5 O 12 can accommodate three Li + ions during the intercalation process to form Li 7 Ti 5 O 12 , resulting in a theoretical specifi c capacity of 175 mA h g − 1 . [ 18 , 20 ] It has been demonstrated that Li 4 Ti 5 O 12 anodes with high performance can be achieved by proper nanostructuring. [ 19 , 21–25 ] Inspired by the successful use of many

The rational design and synthesis of hollow structured functional materials are of great significance as both fundamental challenges in materials science and practical solutions for efficient energy utilization in modern society. The unique structural features of hollow functional materials bring outstanding electrochemical properties for both energy storage and electrocatalysis. However, conventional templating methods are normally less efficient in constructing hollow structures with desirable compositions and architectures. In the past decade, many novel synthetic approaches directly converting templates into hollow structures have been developed. Collectively termed as the "self-templated" strategy, it makes use of various physical/chemical processes to transform solid templates into hollow structures of target materials. Of particular note is the outstanding capability to construct complex hollow architectures of a wide variety of inorganic or hybrid functional materials, thus providing effective solutions for various electrochemical energy applications. In this Account, we present the recent progress in self-templated formation of hollow structures especially with complex architectures, and their remarkable performance in electrochemical energy-related technologies. These advanced self-templated methods are summarized as three categories. "Selective etching" creates hollow structures from solid templates of same materials by removing some of the internal parts, forming multishelled or unusual hollow architectures. "Outward diffusion" utilizes the relocation of mass in templates from inner region to outer region driven by various mechanisms, to construct hollow structures with multiple or hierarchical shells. "Heterogeneous contraction" typically applies to thermally decomposable templates and generates various hollow structures under nonequilibrium heating conditions. We further demonstrate some remarkable electrochemical properties of such hollow structures in virtue of their exceptional composition-/structure-induced merits. As electrode materials for lithium-ion batteries, hybrid or multishelled metal oxides exhibit high cyclability because of their capability to well accommodate the lithium insertion strain. Also the rate capability is effectively improved by the fast lithium insertion/deinsertion in multishelled or hierarchical hollow structures. These exceptional structural merits also significantly enhance the reaction kinetics and prolong the cycling lifetime of metal-sulfides-based electrodes, which enables the assembly of hybrid supercapacitors with high energy and power densities. On the other hand, multicompositional hollow structures with large exposed surface area and rich open pore channels offer abundant robust active sites and fast charge/mass transport for electrocatalytic reactions. These studies demonstrate that the versatility and superiority of self-templated methods for hollow structured functional materials have greatly promoted their applications for electrochemical energy storage and conversion. With continued research efforts, we are expecting greater and broader impacts brought by the rapidly growing family of hollow structures formed by self-templated methods.

The one-step synthesis method of nitrogen doped microporous carbon monoliths derived from biomass with high-efficiency is developed using a novel ammonia (NH3)-assisted activation process, where NH3 serves as both activating agent and nitrogen source. Both pore forming and nitrogen doping simultaneously proceed during the process, obviously superior to conventional chemical activation. The as-prepared nitrogen-doped active carbons exhibit rich micropores with high surface area and high nitrogen content. Synergetic effects of its high surface area, microporous structure and high nitrogen content, especially rich nitrogen-containing groups for effective CO2 capture (i.e., phenyl amine and pyridine-nitrogen) lead to superior CO2/N2 selectivity up to 82, which is the highest among known nanoporous carbons. In addition, the resulting nitrogen-doped active carbons can be easily regenerated under mild conditions. Considering the outstanding CO2 capture performance, low production cost, simple synthesis procedure and easy scalability, the resulting nitrogen-doped microporous carbon monoliths are promising candidates for selective capture of CO2 in industrial applications.

Brought to light: Ag2S–Ag hybrid nanotubes were synthesized by rapid microwave-assisted sulfidation of Ag2CO3 nanorods. The relative amounts of Ag2S and Ag in the hybrid structure can be controlled easily by varying the concentration of the sulfur precursor. The optimized Ag2S–Ag hybrid structure has superior photocatalytic activity (yellow) for both degradation of methyl orange (see graph) and reduction of aqueous CrVI under visible-light irradiation.

One-dimensional (1D) hierarchical structures composed of Ni3S2 nanosheets grown on carbon nanotube (CNT) backbone (denoted as CNT@Ni3S2) are fabricated by a rational multi-step transformation route. The first step involves coating the CNT backbone with a layer of silica to form CNT@SiO2, which serves as the substrate for the growth of nickel silicate (NiSilicate) nanosheets in the second step to form CNT@SiO2@NiSilicate core-double shell 1D structures. Finally the as-formed CNT@SiO2@NiSilicate 1D structures are converted into CNT-supported Ni3S2 nanosheets via hydrothermal treatment in the presence of Na2S. Simultaneously the intermediate silica layer is eliminated during the hydrothermal treatment, leading to the formation of CNT@Ni3S2 nanostructures. Because of the unique hybrid nano-architecture, the as-prepared 1D hierarchical structure is shown to exhibit excellent performance in both supercapacitors and photocatalytic H2 production.

Hierarchical three-dimensional (3D) vanadium oxide microstructures, including urchin-like microflowers, nanohorn-structured microspheres, nanosheet-assembled microflowers, and nanosheets bundles, are successfully synthesized by a versatile template-free solvothermal method. It is found that the concentration of the precursor (VOC(2)O(4)) solution has a significant effect on the morphologies of the products. As an example, the time-dependent phase and morphology evolution for the urchin-like vanadium oxide microflowers has been investigated in detail. Urchin-like VO(2) microflowers can be self-assembled within 2 h without using any surfactants. After calcination, the VO(2) microflowers can be easily transformed to urchin-like V(2)O(5) microstructures. The as-obtained V(2)O(5) microflowers are highly porous with a specific surface area of 33.64 m(2) g(-1). When evaluated as a cathode material for lithium-ion batteries, the V(2)O(5) sample delivers very high specific discharge capacity of 267 mA h g(-1) at a current density of 300 mA g(-1). Further, it also exhibits improved cycling stability. The excellent electrochemical performance is attributed to multiple advantageous structural features, including the nanosized building blocks, high porosity, and the 3D hierarchical microstructures.

In this work, we report a facile approach to mass produce carbon-coated MoS2 (C-MoS2) nanorods with high uniformity. The C-MoS2 nanorods are prepared using MoO3 nanorods as the precursor via a sulfidation and subsequent chemical vapor deposition (CVD) of an amorphous carbon layer. When evaluated as an anode material for lithium-ion batteries, the C-MoS2 nanorods exhibit improved reversibility and cycling performance compared with the bare MoS2 nanorods. A high capacity of 621 mA h g−1 can be retained after 80 cycles at a current density of 200 mA g−1. The rate capability of the C-MoS2 nanorods is also improved. The carbon layer is believed to better retain the structure upon prolonged cycling and to improve the conductivity of the material. This simple strategy using gas-phase sulfidation and CVD carbon coating could also be applied to prepare other nanostructured carbon-coated metal sulfides. Keywords: MoS2, Nanorods, Carbon coating, Lithium-ion batteries, Anode

Unionicola (Wolcottatax) arcuata (Wolcott, 1898) (Acari: Hydrachnidia: Unionicolidae) commonly occurs in parasitic association with Cristaria plicata (Leach), Anodonta woodiana elliptica (Heude) or Anodonta woodiana pacifica (Heude) during one or more stages of its life cycle. The mitochondrial 12S rRNA gene was sequenced and analysed from U. arcuata obtained from nine populations of these freshwater mussels from six large lakes in the middle and lower reaches of the Yangtze River, China. The 382 base sequence alignments for these nine populations of U. arcuata had two gaps and contained 51 (13.4%) variable nucleotides. The pairwise divergences among U. arcuata sequence data ranged from 0 to 10.9%, with the lowest intraspecific divergences (0–0.5%) observed among U. arcuata obtained from the same host species and the highest intraspecific divergences (6.7–10.9%) found among U. arcuata from different species of hosts. The results of sequence alignment and divergence were consistent with the heterogeneity i...

IO N Nanostructured materials with controlled shapes and structures have drawn considerable attention for both fundamental research and practical applications. [ 1–5 ] Particularly, onedimensional (1D) nanostructures such as nanowires, nanorods, and nanotubes are of great importance owing to their unique physicochemical properties and anisotropic structures. [ 6–9 ] 1D nanostructures of a wide variety of materials have been successfully synthesized, including carbons (e.g., carbon nanotubes [ 10 ]

Layered protonated titanates (LPTs), a class of interesting inorganic layered materials, have been widely studied because of their many unique properties and their use as precursors to many important TiO(2)-based functional materials. In this work, we have developed a facile solvothermal method to synthesize hierarchical spheres (HSs) assembled from ultrathin LPT nanosheets. These LPT hierarchical spheres possess a porous structure with a large specific surface area and high stability. Importantly, the size and morphology of the LPT hierarchical spheres are easily tunable by varying the synthesis conditions. These LPT HSs can be easily converted to anatase TiO(2) HSs without significant structural alteration. Depending on the calcination atmosphere of air or N(2), pure anatase TiO(2) HSs or carbon-supported TiO(2) HSs, respectively, can be obtained. Remarkably, both types of TiO(2) HSs manifest excellent cyclability and rate capability when evaluated as anode materials for high-power lithium-ion batteries.

High-stability Pt electrocatalysts have been prepared using hierarchical CNT@TiO2 structures composed of TiO2 nanosheets grafted on the CNT backbone as the support. The as-prepared Pt/CNT@TiO2 electrocatalysts manifest high electrocatalytic activity with greatly improved stability compared to conventional CNT or carbon black supported Pt electrocatalysts.

TiO2 nanoparticles-decorated graphene nanosheets have been prepared by a facile hydrothermal method. After depositing Pt nanoparticles exclusively around the interface between TiO2 and rGO, the obtained Pt/TiO2@rGO electrocatalyst exhibits remarkably enhanced electrocatalytic performance, which could be attributed to the unique structure and some possible synergetic effect from the 3-phase Pt–TiO2–rGO junctions.