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Ingenious morphology design and doping engineering have remarkable effects on enhancing conductivity and reducing volume expansion, which need to be improved by transition metal oxides serving as anode materials for lithium-ion batteries. Herein, S0.15–Fe2O3@C nano-spindles with a hierarchical porous structure are obtained by carbonizing MIL-88B@PDA and subsequent high-temperature S-doping. Kinetic analysis showed that S-doping increases capacitive contribution, enhances charge transfer capability and accelerates Li+ diffusion rate. Therefore, the S0.15–Fe2O3@C electrode exhibits superior lithium storage performance with a remarkable specific capacity of 1014.4 mA h g−1 at 200 mA g−1, ultrahigh rate capability of 513.1 mA h g−1 at 5.0 A g−1, and excellent cycling stability of 842.3 mA h g−1 at 1.0 A g−1 after 500 cycles. Moreover, the size of S0.15–Fe2O3@C particles barely changed after 50 cycles, indicating an extremely low volume expansion, related to the carbon shell, fine Fe2O3 nanoparticles, abundant voids inside, and improved kinetics. This strategy can be applied to other metal oxides for synthesizing anodes with high-rate capability and low volume expansion. [ABSTRACT FROM AUTHOR]

All-solid-state Li-ion batteries, have become increasingly important because of their highly reliable solid electrolyte materials. Flexible solid polyethylene oxide (PEO) based electrolytes have been widely studied. Nevertheless, this material exhibits low lithium-ion conductivity. Herein, we report the optimisation of the composition of PEO/polyvinylidene fluoride (PVDF)-based electrolytes to enhance ionic conductivity. When the weight ratio of lithium bis(trifluoromethane sulphonyl)imide and PEO/PVDF is 1:5 (LiTFSI:PEO/PVDF = 1:5), maximum conductivities are 2.98 × 10−5 S cm−1 at 30°C and 5.56 × 10−4 S cm−1 at 60°C. Furthermore, the all-solid-state battery using this solid electrolyte film, a Li metal anode, and a LiFePO4 cathode delivers initial discharge capacities of 149.6 mAhg−1 (0.1 C, 60°C) and 130.2 mAh g−1 (0.5 C, 60°C). Meanwhile, the solid-state lithium battery also presents good cycling performance and excellent rate capability at 60°C. [ABSTRACT FROM AUTHOR]

In this study, we adopt a facile two-step annealing strategy to synthesize different structural 3D Fe2O3 micro-cubes and 3D Fe3O4 micro-cubes using Prussian blue (PB) as a precursor. Importantly, the effect of the annealing temperature on the structural evolution of the products is systematically investigated. In the first step, the 3D Fe2O3 cubes are synthesized by annealing PB in air. With the increasing temperature, the morphology of 3D Fe2O3 changes from the cube with pores on surface to the hollow cube assembled by nanosheets (HCNSs), which is caused by the higher gas generation and overflow. In the second step, 3D Fe3O4 cubes are obtained by annealing 3D Fe2O3-HCNSs in the atmosphere of Ar/H2. With the increasing temperature, the morphology of 3D Fe3O4 changes from the hollow cube assembled by nanosheets to the hierarchical porous hollow cube assembled by fine nano-particles (denoted as HCNPs), an interesting micro/nano-structure that is obtained by recrystallization and reduction. When the temperature is excessive, the building blocks become larger and the 3D structures collapse. Furthermore, we evaluate the electrochemical performance of 3D hierarchical porous Fe3O4-HCNPs as the anode materials for Li-ion batteries. They exhibit enhanced electrochemical performance, characterized by a large reversible capacity of 1193.6 mA h g−1 at a current density of 100 mA g−1 and a high rate capacity of 942.1 mA h g−1 at 1000 mA g−1. This superior performance is due to the unique structural advantages of 3D hierarchical porous Fe3O4-HCNPs, including abundant meso/micro-pores, hollow structure and robust structural stability. [ABSTRACT FROM AUTHOR]

Abstract As cathode materials for Li-ion batteries (LIBs), V 2 O 5 , possessing a large-spaced and open layered crystal structure, have attracted considerable attention due to their distinct advantages of high specific capacity, abundant raw materials and low cost. Although low-dimensional nanostructured V 2 O 5 can increase the discharge capacity of LIBs, it still suffers from poor cycling and rate performance due to serious self-aggregation and pulverization. Building micro/nano-structures is a highly promising method to address the above issues. Herein, we propose a facile oxidation strategy to successfully synthesize the unique 3D hierarchical porous sponge-like V 2 O 5 micro/nano-structures (V 2 O 5 -SLMNSs) by using the structure-similar sponge-like VO 2 (B)@C micro/nano-structures as a precursor. Importantly, as-synthesized V 2 O 5 -SLMNSs possess the distinct structural advantages of a robust structure with large surface area and abundant meso/micropores, which are beneficial for achieving a better electrochemical performance. Specific capacity during the second discharge for V 2 O 5 -SLMNSs is 232 mAh/g at 100 mA/g, with 87% of the capacity being maintained after 50 cycles, which is considerably higher than the discharge capacity (190 mAh/g) in the second cycle and the value for the capacity retention (69%) of 1D V 2 O 5 nanoribbons. Thus, as-synthesized V 2 O 5 -SLMNSs are promising cathode materials for the next-generation LIBs. Graphical abstract Image 1 Highlights • Unique 3D sponge-like V 2 O 5 micro/nano-structures (V 2 O 5 -SLMNSs) are synthesized. • V 2 O 5 -SLMNSs possess robust structure, large surface area and conductive frameworks. • V 2 O 5 -SLMNSs exhibit the greatly improved electrochemical performance. [ABSTRACT FROM AUTHOR]

The increasing demand for high-energy-density portable electronics and electric vehicles is sparking an intensive research interest in lithium-ion batteries. Transition metal oxides/carbonaceous matrix hybrids have attracted tremendous attention to produce the next-generation lithium-ion batteries (LIBs). This paper initially reports that the tree-like Li 2 MnO 3 @carbon nanotube (CNT) hierarchical architecture can achieve the long-life lithium storage performance. Li 2 MnO 3 nanoparticles of the hybrid with lattice Li + , as the anode material for LIBs, exhibits a reversible capacity of over 740 mAh/g at a current density of 0.5 A/g after 350 cycles, indicative of superior cyclic stability and excellent rate performance. XPS and XRD patterns reveal that LiOH in the anode material, which originates from the conversion reaction, is further discovered to be available and reversible for surface-enhanced lithium storage. Surface-enhanced lithium storage contributes to the over-compensation and increased capacity. [ABSTRACT FROM AUTHOR]

As intercalation-type anode materials for Li-ion batteries (LIBs), the commercially used graphite and Li4Ti5O12 exhibit good cycling and rate properties, but their theoretical specific capacities are too low to meet the ever-growing demands of high-energy applications such as electric vehicles. Therefore, the development of new intercalation-type anode materials with larger capacity is very desirable. Herein, we design and synthesize novel 3 D hierarchical porous V2O3@C micro/nanostructures consisting of crumpled nanosheets, through self-reduction under annealing from the structurally similar VO2 (B)@C precursors without the addition of any other reducing reagent or gas. Excitingly, it is found for the first time through ex situ XRD technology that V2O3 is a new, promising intercalation-type anode material for LIBs with a high capacity. V2O3@C micro/nanostructures can deliver a large capacity of 732 mAh g−1 without capacity loss at 100 mA g−1 even after 136 cycles, as well as exhibiting excellent cycling and rate performances. The application of V2O3 for Na-ion batteries (NIBs) is elaborated for the first time, and excitingly, it is found that V2O3@C micro/nanostructures may be promising anode materials for NIBs. [ABSTRACT FROM AUTHOR]

• ZnS-MoS 2 /rGO composites were synthesized by using a one-step high-temperature mixing method (HTMM) under hydrothermal conditions. • The synthesis approach is implemented by using the self-designed dual-chamber Teflon lined reactor and ingenious rotation process. • The synergistic effect in the hybrid enhances electronic conductivity and structural stability. • The ZnS-MoS 2 /rGO@C composites with large proportion of pseudocapacitive contribution exhibits excellent rate capability. Hybrid-structured coupling metal dichalcogenides with carbon materials serve as prospective anode materials for lithium-ion batteries (LIBs) due to their high electrical conductivity, rich active sites, and Li+ diffusion path for Li+ storage. In the present work, graphene-wrapped ZnS−MoS 2 @carbon composites (ZnS−MoS 2 /rGO@C) are synthesized via high-temperature mixing during the hydrothermal and carbonation processes. The as-prepared ZnS−MoS 2 /rGO@C composites display alleviated volume change in the electrochemical process, increased Li+ diffusion speed, and improved conductivity, which are caused by the synergic effect of phase boundaries and hierarchical construction. Therefore, the ZnS−MoS 2 /rGO@C composites show superior lithium storage capacity and structure stability, and possess ultrastable cycle (581.0 mAh g−1 after 500 cycles at 1 A g−1) and good rate performance (310.7 mAh g−1 at 5 A g−1). This work confirms that anode materials with a hybrid structure can be rationally engineered for high-performance LIBs with superior cycle durability and good rate capability. [Display omitted] [ABSTRACT FROM AUTHOR]

• 2D V 6 O 13 nanosheets were one-step synthesized using URH for the first time. • URH is a simple, low–energy consumption, time-saving, and efficient synthesis technology. • The as-synthesized material has a superior rate/cycle performance and enhanced reversible capacity. The ever-growing demands of Lithium-ion batteries (LIBs) for high-energy and long-life applications, such as smart grids and electrical vehicles, have drawn great research interest. Herein, 2D V 6 O 13 nanosheets with good crystallinity and robust configuration are in situ synthesized by applying an interesting one-step uniform rotate hydrothermal method. X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy were carried out to characterize the crystal structure and micromorphology of the samples. In addition, the lithium storage performance of the sample was investigated through cyclic voltammetry, electrochemical impedance spectroscopy, and charge/discharge tests. Their capacity is up to 240 mAh g-1 at a current density of 100 mA g-1, corresponding to an initial Coulombic efficiency as high as 98.41%. Moreover, the capacity of 199 mAh g-1 can be delivered at a large current density of 500 mA g-1, and 87% of the capacity can be retained after 100 cycles. Even at a larger current density of 1000 mA g-1, they can still deliver a high capacity of 155.7 mAh g-1, and nearly 80% of the initial capacity can be kept after 300 cycles. This result is much higher than that of V 6 O 13 prepared by traditional hydrothermal method under the same test conditions. These results demonstrate that the as-synthesized 2D V 6 O 13 nanosheets by uniform rotate hydrothermal method have a promising future for high-rate and long-life cathode materials of next-generation LIBs. [ABSTRACT FROM AUTHOR]

High‐capacity vanadium‐based oxides are one kind of promising energy storage materials, especially for electric vehicles. It has become a hot research issue to synthesize vanadium‐based oxides from low‐dimensional nanostructures to 3D micro/nano‐structures and free‐standing‐electrodes. It will become a very attractive and practical strategy in the future to fabricate the “vanadium oxides‐based cathode/solid electrolyte/Li metal anode‐type” all solid‐state secondary‐ion batteries. This is reported by Pengcheng Liu, Kongjun Zhu, and co‐workers in article number 1700547. [ABSTRACT FROM AUTHOR]

Rapid developments in revolutionary electric vehicles have led to an increase in the energy-density and cycling-life requirements for Li-ion batteries (LIBs). The binary transition metal oxide NiCo 2 O 4 is attracting considerable attention due to its much larger specific capacity than graphite. However, NiCo 2 O 4 suffers from poor cycling performance owing to a large volume change during cycling. To address this problem, we proposed an easy strategy to fabricate in situ carbon-coated NiCo 2 O 4 bilayered hybrid nanostructural arrays supported on Ni foam (denoted as NiCo 2 O 4 @C BHNAs–NF) as free-standing anodes for LIBs through a sucrose-assisted hydrothermal method. The in situ-synthesized uniform carbon shell can simultaneously buffer the volume change during cycling and increase the conductivity. The micro/nano-structure also possessed outstanding structural advantages, such as large surface area and hierarchical porous characters, enabling NiCo 2 O 4 @C BHNAs–NF to have excellent electrochemical performance. Its capacity can reach 1298 mAh/g at a current density of 100 mA/g, and 86% of the initial capacity can be retained after 100 cycles. All these results revealed that NiCo 2 O 4 @C BHNAs–NF was a promising candidate anode for next-generation LIBs. [ABSTRACT FROM AUTHOR]

As one of binary transition metal oxides, NiCo 2 O 4 (NCO) suffers from several problems like self–agglomeration and drastic volume change when used as an anode for lithium–ion batteries (LIBs). Herein, we propose a facile one–step hydrothermal method combined with heat treatment to prepare a hierarchical micro–nano hydrangea–like NiCo 2 O 4 /V 2 O 3 composite array (denoted as NCO/VO) on a nickel foam substrate as a free–standing anode for LIBs. The V 2 O 3 is introduced to form a composite structure with NCO, improving the electronic and ionic conductivity of the electrode. The synergistic effect of porosity, composite structure and micro–nano architecture offers the electrode excellent electrochemical performance. The specific capacity of the as–prepared electrode is 1155.6 mA h g−1 after 200 cycles under the current density of 100 mA g−1, with a retention ratio of 91.02 %. When the current density rises to 1000 mA g−1, it delivers a specific capacity of 750 mA h g−1, showing excellent rate performance. This work demonstrates that NCO/VO–NF is a promising candidate anode for next–generation LIBs. [Display omitted] • A first–time synthesis of NiCo 2 O 4 –V 2 O 3 composite arrays on nickel foam by a facile method. • The unique hierarchical micro–nano hydrangea–like morphology. • Improved electrochemical performances as an anode for LIBs by introducing V 2 O 3. [ABSTRACT FROM AUTHOR]

With the wearable electronics progressing rapidly, the demand for flexible, long-life and low-cost electrodes of Li-ion batteries (LIBs) becomes more and more urgent. Due to the abundant resources and low cost, silica (SiO 2 ), especially the amorphous one, has attracted a lot of interests on the application of anode materials for LIBs. However, SiO 2 still suffer from the poor cycling performance mainly caused by the huge volume change during cycling like other alloy-type materials. Furthermore, it remains a challenge to fabricate the SiO 2 –based flexible electrode. Herein, we propose a facile in situ strategy to fabricate the electrospun robust free-standing SiO 2 /carbon nanofibers (denoted as in-SCNFs) film constructed by N-doped carbon nanofibers encapsulating uniformly amorphous SiO 2 nanoparticles. The in situ synthesized finer SiO 2 nanoparticles in the in-SCNFs are uniformly encapsulated in flexible carbon nanofibers, which can effectively buffer the volume change. Furthermore, the robust in-SCNFs film possesses the excellent mechanical flexibility and strength. So, when served as the free-standing anode of LIBs, the in-SCNFs film exhibits superior cycling performance. A discharge specific capacity of 405 mAh/g can be delivered even after a long-term 1000 cycles at a large current density of 500 mA/g, and the retention is up to 115%. It is an exciting finding that the in-SCNFs film is also a long-life anode of Na-ion batteries (NIBs). The 99% of initial capacity can be kept after 250 cycles at 500 mA/g. To our best knowledge, this is the first report on the application of SiO 2 /C composite for NIBs. These results suggest that the as-fabricated in-SCNFs film can become one promising free-standing long-life anode for LIBs and NIBs. [ABSTRACT FROM AUTHOR]

The sluggish Li‐ion diffusivity in LiFePO4, a famous cathode material, relies heavily on the employment of a broad spectrum of modifications to accelerate the slow kinetics, including size and orientation control, coating with electron‐conducting layer, aliovalent ion doping, and defect control. These strategies are generally implemented by employing the hydrothermal/solvothermal synthesis, as reflected by the hundreds of publications on hydrothermal/solvothermal synthesis in recent years. However, LiFePO4 is far from the level of controllable preparation, due to the lack of the understanding of the relations between the synthesis condition and the nucleation‐and‐growth of LiFePO4. In this paper, the recent progress in controlled hydrothermal/solvothermal synthesis of LiFePO4 is first summarized, before an insight into the relations between the synthesis condition and the nucleation‐and‐growth of LiFePO4 is obtained. Thereafter, a review over surface decoration, lattice substitution, and defect control is provided. Moreover, new research directions and future trends are also discussed. [ABSTRACT FROM AUTHOR]

Hydrothermal synthesis of high-performance LiFePO4 nanocrystals in pure water represents a green and sustainable approach to fabricate model cathode materials for lithium ion batteries. However, fundamental and technological hurdles in terms of yield and cost remain to be overcome, though strenuous efforts have been devoted to this challenging approach. Herein, we report a microwave-assisted hydrothermal strategy that enables scalable green synthesis of high-performance LiFePO4 nanocrystals using inexpensive chemical reagents, namely, lithium hydroxide, ferrous sulfate and phosphoric acid in pure water without involving any organic solvents or surfactants. Three critical issues regarding the hurdles are simultaneously addressed. First, the dream of recycling the lithium source, the most valued reagent, in the hydrothermal synthesis comes true, which substantially reduces synthesis cost; second, to the best of our knowledge, a record high volume specific yield of more than 1.3 mol L−1 is achieved. Third, the as-synthesized phase-pure LiFePO4 nanocrystals exhibit excellent electrochemical properties including high capacity and long cyclability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon coating layer enhances structural stability of WS 2 /MoS 2 @C/rGO composites. • Hollow WS 2 /MoS 2 @C/rGO microspheres contribute to the infiltration of electrolyte. • WS 2 /MoS 2 @C/rGO composites show notable electrochemical properties in LIB and SIB. In this work, the hollow WS 2 /MoS 2 @carbon microspheres anchored on graphene were successfully fabricated via the versatile solvothermal and hydrothermal methods. The WS 2 /MoS 2 heterostructure can offer a great charge transport driving force by forming a built-in electric field. Moreover, the incorporation of conductive carbon materials from carbon layer and graphene can mitigate the enormous volume variation and pulverization of electrode materials in the cycle process and ensure fast electronic/ionic transfer kinetics. Thus, the hollow WS 2 /MoS 2 @carbon/rGO displays superior rate performance and cycling durability in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). It achieves a excellent capacity of 701.8 mAh g−1 at 1 A g−1 after 550 cycles for LIBs. The WS 2 /MoS 2 @carbon/rGO composite displays superior rate capability (320.5 mAh g−1 at 5 A g−1) and cycling durability (411.8 mAh g−1 at 500 mA g−1 after 250 cycles) for SIBs. This work shows a effective strategy for constructing the bimetallic sulfide for energy storage. [ABSTRACT FROM AUTHOR]