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Constructing Two-dimensional (2D) nanostructures into 3D architecture towards specific applications is desirable but challenging. In this work, we construct 2D Cu 3 V 2 O 7 (OH) 2 ·2H 2 O nanoplates into 3D nanoflowers via Cu 2 O sacrificial template method. The employed Cu 2 O nanocubes not only serve as template but also supply the Cu resource during the synthesis strategy. The morphology and structure of Cu 3 V 2 O 7 (OH) 2 ·2H 2 O are characterized by XRD, SEM, and TEM techniques. The Cu 3 V 2 O 7 (OH) 2 ·2H 2 O nanoflowers show combined structural benefits for electrochemical performance, such as high surface area and short migration path for lithium storage, as well as tunnels for electrolyte filtration. Therefore, high capacity, stable cyclability, and especially high initial coulombic efficiency of 91.3% are obtained from Cu 3 V 2 O 7 (OH) 2 ·2H 2 O nanoflowers, making it a promising anode material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: In this manuscript, we present a facile and friendly wet chemical method to prepare monodisperse SnO2 nanocrystals assembled on reduced graphene oxide (RGO). Aided with sodium dodecyl sulfonate, small SnO2 nanoparticles (∼5 nm) are deposited onto the flexible support evenly and tightly. A cheap compound, urea, is used for the controlled precipitation of SnO2 and the reduction of graphene oxide. When tested as the anode material, the hybrid composite electrode delivers excellent cyclability at high current density, such as high reversible capacity over 1000mAhg−1 after 400 cycles at 0.5Ag−1 and ∼560mAhg−1 after 400 cycles at 1Ag−1. The composites also exhibit superior rate capability varying from 0.1 to 4Ag−1, and possess capacity of 423mAhg−1 at 4Ag−1. This synthesis strategy seems to be suitable for industrial production and can also be extended to produce a variety of metal oxide/RGO composites. [Copyright &y& Elsevier]

Highlights: [•] Mesoporous Co3O4 octahedra have been prepared with simple sol-gel method. [•] Porous structure buffers the volume change and shortens the diffusion path of Li+. [•] Anisotropy octahedral morphology guarantees structural stability. [•] It exhibits high capacity, superior capacity retention and excellent rate capability. [Copyright &y& Elsevier]

Abstract: In this manuscript, porous Co3O4 nanorods are prepared through a two-step approach which is composed of hydrothermal process and heating treatment as high performance anode for lithium-ion battery. Benefiting from the porous structure and 1-dimensional features, the product becomes robust and exhibits high reversible capability, good cycling performance, and excellent rate performance. [Copyright &y& Elsevier]

Abstract: Novel porous spherical CuO xerogels constructed by crystalline nanorods (100–200nm in length and 20–40nm in diameter) are synthesized as anode materials in lithium-ion batteries. Aided with the soft-template of P123, the product possesses abundant mesopores centered at ~7.3nm and high surface area of 63.1m2 g−1. Benefiting from its structural features, including porous structure, one-dimensional structure, and oriented growth along (111) plane, the presented sample delivers high reversible capacity (646.7mAhg−1 at 0.2C after 150 cycles), excellent cyclic performance (88% capacity retention after 150 cycles), and superior rate capability (510mAhg−1 at 0.5C). [Copyright &y& Elsevier]

Abstract: We report a two-step approach to synthesize SnO2–Fe2O3@C nanocomposite as a good candidate for high-performance lithium-ion batteries (LIBs) anodes. In this route, the SnO2–Fe2O3@polyaniline is first prepared with in situ polymerization in sol, followed by a carbonized transformation process. The growth of metal oxides particles is firstly suppressed by the polyaniline (PANI) on their outer surface in the in-situ polymerization route and secondly restricted by fully coating of carbon shell in thermal treatment, which forms by in situ carbonization of the polymer. Due to the unique structure and a so-called synergistic effect between SnO2 and Fe2O3, an excellent capacity over 1000 mAh g−1 is maintained after 380 cycles at current density of 400 mA g−1. The key insight is that the composite anode presented here achieves fully reversible Li insertion/extraction reaction and maintains high capacity for a long cycling life at high current density, and is realized as promising high-performance LIBs anode materials. [Copyright &y& Elsevier]

Vanadium oxides are potential anode materials for sodium-ion batteries, however, their application is limited for their rate capability and cycle life. Herein, hollow spheres of Co-doped V 2 O 3 enveloped in N-doped carbon (Co-V 2 O 3 @NC) are prepared through a hydrothermal step with the following sintering process. The hollow spherical structure supplies short distance and large area for fast ion transfer kinetics, which also provides voids to ease the volume expansion. The strong coupling between Co-V 2 O 3 nanoparticles and carbon layer constitutes a solid structure that enhances the conductivity and keeps electrode integrity. Co-doping introduces plenty of active sites for surface capacitance behavior and accelerates charge transfer. On account of the benefits, Co-V 2 O 3 @NC exhibits excellent Na+ storage properties as anode, including high capacity of 338.5 mAh g−1 at 0.1 A g−1, stable cycling capability of 240 mAh g−1 after 1000 cycles at 1 A g−1, and excellent rate performance. This work describes the importance of constructing specific structured materials for advanced anodes. [Display omitted] • Hollow spheres of Co-doped V 2 O 3 enveloped in N-doped carbon are prepared. • Hollow structure accelerates ion transfer kinetics and buffers volume expansion. • Co-doping provides sites for surface-controlled sodium storage. • Carbon coating improves conductivity and benefits electrode integrity. • High-performance sodium storage performances are acquired. [ABSTRACT FROM AUTHOR]

Heterostructure fabrication is believed to acquire promoted charge transfer and improved surface storage contribution, thus obtaining high-performance anodes for sodium-ion batteries. Herein, the simultaneous phosphatization and selenization of polydopamine functionalized ZIF-67 is adopted to engineer N-doped carbon coated Co(PO 3) 2 /CoSe 2 heterostructure. The hetero-interface with plenty of surface sites is activated with large surface reaction and fast sodium ion transport dynamics. The multiphase synergism and carbon coating layer assure high conductivity and structural stability. The designed sample delivers impressive anode performance, exhibiting a high sodium storage capacity of 333.4 mAh g−1 at 0.1 A g−1 and 192.7 mAh g−1 after 1000 cycles at 2 A g−1. This simple and reasonable method can be utilized to construct other transition metal based heterostructures with multiphase synergism for the application of advanced anodes. [Display omitted] • N-doped carbon coated Co(PO 3) 2 /CoSe 2 heterostructure is prepared. • Heterostrucrue favors surface-controlled pseudocapacitive sodium storage. • N-doped carbon shell enhances conductivity and keeps electrode integrity. • Multiphase synergism benefits electrochemical kinetics and structure stability • Large/fast sodium storage properties with excellent stability are obtained. [ABSTRACT FROM AUTHOR]

How to well retain the specific structures during the thermal transformation from metal hydroxide, carbonate, or acetate precursors to metal oxides is a challenging mission. A novel SiO 2 scaffold method has been developed for the first time to synthesize 1D porous Fe 2 O 3 nanostructures. The coated SiO 2 shell supplies additional mechanical support to prevent the collapse of nanorod precursors during the heat-treatment. The obtained 1D porous nanostructures possess great benefits for electrochemical lithium storage, including high contact surface area between active materials and electrolyte, pores for easily electrolyte penetration, and shortened migration path for Li + and electron. When tested as anode materials for lithium-ion batteries, the sample delivers high capacity and improved cyclic stability. [ABSTRACT FROM AUTHOR]

Exploration of mixed transition metal oxides with specific nanostuctures for high-performance lithium storages is an urgent but still challenging desire. Mesoporous FeCo 2 O 4 octahedra are synthesized for the first time with evaporation-induced self-assembly method as advanced anode materials for lithium-ion batteries. Endowed with the combined benefits of multicomponent effect, octahedral structure stability, and mesoporous features, the sample delivers excellent electrochemical performance, including large, fast, and stable cyclic performance (1101 mAh g −1 at 1 A g −1 after 200 cycles), as well as the best high-rate performance ever reported for FeCo 2 O 4 (518 mAh g −1 at 10 A g −1 ). [ABSTRACT FROM AUTHOR]

To pursue anode materials with large and fast lithium storage properties, the carbon entrapped Fe 3 O 4 nanoparticles are directly grown on Ni foam as binder-free integrated electrode for the first time. The synthesis strategy includes an in situ polymerization method and the following thermal annealing process. The charge transfer is dramatically improved due to the advantageous features of high electric conductivity of carbon layer and Ni substrate, nanosized Fe 3 O 4 particles, close contact between active materials and current collector. The carbon shell can also buffer the volume changes of Fe 3 O 4 during the lithiation/delithiation. Therefore, the integrated electrode exhibits high capacity, superior rate capability, and good cycling stability. [ABSTRACT FROM AUTHOR]

• S, N co-doped carbon nanosheets are prepared as SIBs anode. • S, N co-doping endows enlarged interlamellar spacing and defective active sites for improved sodium storage. • S, N co-doping improves Na+ diffusion coefficient. • High capacity of 270 mAh g−1 is obtained at 0.1 A g−1 after 100 cycles. • Capacity of 100 mAh g−1 is achieved at high rate of 1 A g−1 after long-term 1000 cycles. Heteroatom doping into specific nanostructure is believed as the leading solution for developing the advanced carbon materials for sodium ion batteries (SIBs), however, the preparation and understanding of heteroatoms co-doped carbon anodes are still challenging. Herein, the sulfur and nitrogen co-doped (weight content of 15.64% for N and 3.1% for S) carbon nanosheets (SNC) are prepared by treating nitrogen-rich carbon nanosheets with sublimation sulfur. The S, N co-doping is responsible for the enlarged interlamellar spacing of 0.38 nm and abundant defect-introduced active sites. These structure features combined with the advantage of nanosheet are significant for activating sodium ion storage properties, endowing SNC with high Na+ storage capacity of 270 mAh g−1 at 0.1 A g−1 and 100 mAh g−1 at 1 A g−1 after 1000 cycles. More importantly, the kinetic analysis is carried out to illustrate that S, N co-doping can improve the Na+ diffusion coefficient in carbon anode and enhance the ion storage. This work deepens the understanding on the boosting effect of heteroatoms dual-doping for the sodium ion storage of carbon materials, which conduces to development of advanced heteroatom doped carbon anodes for SIBs. [ABSTRACT FROM AUTHOR]

Developing advanced electrode materials for sodium storage is hindered by the sluggish Na+ diffusion kinetics and terrible structure damage. Pseudocapacitance is believed as a promising solution to supply fast, large and stable sodium storage via surface-controlled behavior. Herein, a hybrid material approach is implemented to pursue pseudocapacitance contributed sodium storage by constructing nitrogen-doped graphene nanosheets packed SnP 2 O 7 particles. The rationally selected components and specific structure also provide advantages for electrolyte penetration and Na+ diffusion, fast charge transfer, and structure stability. Hence, the developed composite delivers anode performances for sodium storage with high capacity of 423 mAh g−1 at 0.1 A g−1, good rate performance of 206 mAh g−1 at 2 A g−1, and stable cyclic property (retention rate of ∼95% after 1000 cycles at 1 A g−1). Pseudocapacitance contribution is vital for the composite electrode, especially at high rate, dedicating a percentage as high as 89% to the total capacity at a sweep rate of 1 mV s−1. This work demonstrates the promising potential of compositing graphene and conversion reaction material as pseudocapacitive electrode for sodium ion batteries. • N-doped graphene wrapped SnP 2 O 7 particles is prepared as SIBs anode. • Composition and structure characteristics benefit sodium storage. • Pseudocapacitive dominated sodium storage is acquired. • Large/fast sodium storage with excellent stability is obtained. [ABSTRACT FROM AUTHOR]