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In this article, hierarchical hydrangea‐like MoS2/C composites are synthesized through a simple one‐pot solvothermal method followed by heat treatment for the first time. The morphology and electrochemical performance of MoS2/C are largely affected by the solvent composition and carbon content during the solvothermal process. The interlayer distance of few‐layer MoS2 is increased by the insertion of carbon layer for the unique hierarchical hydrangea‐like MoS2/C nanostructure. The cycling performance of MoS2/C is greatly improved because it takes advantage of both good conductivity and structural stability. When tested as an anode of a lithium‐ion battery, the results show that the reversible specific capacity of the MoS2/C electrode is 853.1 mAh g−1 after 80 cycles at a current density of 200 mA g−1 with capacity retention of 98.4%. Especially, when tested under 500 mA g−1, the reversible specific capacity can reach to 780.6 mAh g−1 after 200 cycles. [ABSTRACT FROM AUTHOR]

ZnMn2O4 electrode materials were prepared by directly roasting mixed liquid with sucrose as the soft template. The influences of the amounts of sucrose on the structure, morphology and lithium storage properties of the synthesized ZnMn2O4 electrode materials were studied by XRI). FESEM, and electrochemical performance tests. When the molar ratio of Zn2+ to sucrose in the raw materials was 1:1.5. the prepared ZnMn2O4 sample showed a mixed morphology of irregular particles and nano-sheets. and exhibited the best lithium storage performance. The reversible capacity could reach 575 mAh/g after 200 cycles at 0.5 A/g current density. E-ven at the high current density of 5 A/g. it still delivered a reversible capacity of 295 mAh/g. The electrochemical reaction kinetic analysis showed that the ZMO-1.5 electrode had the lowest electrochemical reaction resistance and the highest lithium ion diffusion coefficient. This study was expected to provide guidance and theoretical reference for the facile and low-cost preparation of high performance ZnMn2O4 electrode materials. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Multiple Sn-MnO nanocores embed in N-doped C 3D interconnected networks. • Enhanced special capacity, cyclic stability and rate capability as anode. • Enhanced properties are due to unique structure and in-depth nanocrystallization. • Unique structure of Sn-MnO nanocores and N-doped C coating yolk-shelled 3D networks. Abstract We develop a novel method combining co-precipitation and post thermal treatment to synthesize Sn-MnO@N-doped carbon yolk-shelled three-dimensional (3D) interconnected networks. In the novel nanostructures, Sn-MnO nanoparticles are wrapped by N-doped amorphous C with 3D interconnected networks to compensate the volume expansion of active substances during Li+ insertion. Owing to the prominent merits of these structural features, Sn-MnO@N-doped carbon composites exhibit high special capacity (1185.9 mAhg−1) and excellent cyclic stability (757.2 mAhg−1 at 0.1 Ag−1 after 200 cycles). Even after 500 cycles, a capacity of 535.8 mAhg−1 at 0.5 Ag−1 can still be maintained. The investigation confirms that the improved performances of the composite can be attributed to the synergistic effects of N-doped carbon coating yolk-shelled 3D interconnected networks, nano-sized Sn-MnO cores and the in-depth nanocrystallization process during intense cycles. This unique structure design of carbon coating Sn-based nanoparticles yolk-shelled 3D interconnected networks can be applied to other anode nanomaterials in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Layered lithium‐rich oxides are recognized as promising cathode materials for lithium‐ion batteries (LIBs), owing to their high‐energy density, high voltage, high specific capacity, and low cost. However, it remains a critical challenge to realize the high capacity of layered lithium‐rich oxides. Herein, we synthesize the Li‐rich Li(Li0.2Ni0.15Mn0.55Co0.1)O2 cathode material by using the sol‐gel method and induced a spinel phase on its surface through carbonization‐reduction engineering. The surface‐modified sample exhibited both improved capacity and rate capabilities. The initial discharge capacity of the treated sample reached 279.6 mAh g−1 at 0.1 C, which was 11 % higher when compared to the as‐prepared sample (252.6 mAh g−1). In addition, a discharge capacity of 239.4 and 235.9 mAh g−1 after 100 cycles at 0.5 C and 1 C (1 C=250 mAh g−1) could be still obtained for the modified sample, respectively. The enhanced properties were attributed to the increased ionic conductivity through the formation of 3D diffusion paths and reduced structural transformation, owing to the spinel structure decoration on the surface. Good soldiers need good armor: A spinel‐coated Li(Li0.2Ni0.15Mn0.55Co0.1)O2 (LNMC‐C) cathode material is synthesized by using a sol‐gel method combined with modification treatment; see picture (a). Benefiting from the 3D diffusion paths and protection function of surface spinel phase, this material exhibits excellent discharge capacity and cyclic stability; see picture (b, c). [ABSTRACT FROM AUTHOR]

One-dimension mesoporous cobalt ferrite (CoFe2O4) nanofibers were prepared by a facile single-nozzle electrospinning technique followed by calcination. The lithium storage properties show that the CoFe2O4 nanofibers obtained at 800 °C deliver an initial discharge capacity of 1888 mAh g−1 and a reversible capacity as high as 942 mAh g−1 after 80 cycles, much higher than those of the samples obtained at 600 °C (1193 and 701 mAh g−1, respectively). The CoFe2O4 nanofibers obtained at 800 °C also demonstrate an excellent rate capability. The improved lithium storage properties of CoFe2O4 nanofibers obtained at 800 °C can be attributed to the unique mesoporous and fibrous structures, as well as the high crystallinity, which provide an easy Li+ diffusion path promote electron transfer, meanwhile preventing volume expansion/contraction during discharge/charge processes. [ABSTRACT FROM AUTHOR]

Multi-yolk-shell SnCo@N-doped carbon nanocages with controllable carbon shell thickness are well fabricated by a novel approach. The multi-yolk-shell SnCo@N-doped carbon nanocages form an enough void volume to compensate the volume expansion of SnCo nanoparticles during Li + insertion. To optimize the electrochemical properties, SnCo@N-doped carbon nanocages with controllable carbon shell thickness can be tailored by coating polydopamine (PDA) with various thicknesses on CoSn(OH) 6 hollow nanocubes in the second step of the synthesis process. Multi-yolk-shell SnCo@N-doped carbon nanocages with the optimized shell thickness exhibit a high initial discharge capacity (1025 mAhg −1 ) and remarkable cyclic stability (611 mAhg −1 after 100 cycles) as Li-ion batteries anode. This work may open a wonderful way for the rational design of alloy@carbon composites with tailorable structures for next-generation anode nanomaterials in Li-ion battery. [ABSTRACT FROM AUTHOR]

Full encapsulation of Sb/MoO x nanoparticles into porous N-doped carbon nanofibers (CNFs) ( denoted as Sb/MoO x @CNFs ) is realized via electrospinning and subsequent annealing and water-washing treatments. The in situ generated NaCl nanoparticles, arising from the reaction between the SbCl 3 and Na 2 MoO 4 precursors, sever as water-removable pore templates, which generate numerous pores within the CNFs after washing with water. When used as anode materials for lithium ion batteries (LIBs), the porous Sb/MoO x @CNFs deliver a high reversible capacity of ∼822 mA h/g at 200 mA/g after 140 cycles, and a stable capacity of ∼ 558 mA h/g even after 500 cycles at a high rate of 1 A/g. The excellent lithium storage performance is attributed to the novel structure characteristics of the hybrid Sb/MoO x @CNFs. The full encapsulation of Sb/MoO x nanoparticles as well as pores into CNFs efficiently buffers the volume changes and facilitates the maintenance of electrode integrity, while the N-doped one-dimensional CNFs not only improve the electronic conductivity but also facilitate the electronic and ionic transportation. Moreover, e x situ TEM measurements clearly support the advantages of such hybrid electrode in LIBs. [ABSTRACT FROM AUTHOR]

SnO 2 @C@MnO 2 hierarchical hollow hybrid nanospheres have been obtained by coating the MnO 2 nanosheet-based hierarchical shell on SnO 2 @C hollow nanospheres via a redox method. The hierarchical hollow hybrid nanospheres are composed of the SnO 2 internal layer with hollow nanostructures, the carbon interlayer and the MnO 2 hierarchical nanostructured external layer built from two dimensional nanosheets. SnO 2 @C@MnO 2 nanomaterials exhibit a large initial discharge capacity (1378 mAhg −1 ), extraordinary cyclic stability (644.5 mAhg −1 after 200 cycles) and rate capability as Li-ion battery anodes. The excellent properties may benefit from the rational design of hierarchical hollow hybrid nanostructures and the synergistic effects between the three layers of SnO 2 , carbon and MnO 2 . [ABSTRACT FROM AUTHOR]

A novel type of porous TiO 2 nanobelts anchored with Sn 3 O 4 nanosheets (TiO 2 nanobelts @Sn 3 O 4 nanosheets) core-shell composites were developed via two-step hydrothermal methods. The structure, morphology, formation mechanism and electrochemical performance of the porous TiO 2 nanobelts coated with mixed transition-metal oxides Sn 3 O 4 nanosheets core-shell composites were researched. The results illustrated that the Sn 3 O 4 nanosheets were uniformly anchored on the surface of the porous TiO 2 nanobelts, which were almost perpendicular to the porous TiO 2 nanobelts. The composites as anode materials exhibited more remarkable electrochemical performances than the Sn 3 O 4 nanosheet and the porous TiO 2 nanobelts, in terms of the cycling performance and rate capability. The initial discharge capacity was 1513.7 mAh/g and the reversible capacity was 659 mAh/g after 50 cycles. This study perhaps inspired the designing of other transition metal oxide-based anode materials with desirable electrochemical performance for applications of lithium ion batteries. [ABSTRACT FROM AUTHOR]

Structure and morphology of molybdenum disulfide (MoS2) play an important role in improving its reversible lithium storage and sodium storage as anodes. In this study, a facile method is developed to prepare C/C@SnO2/MoS2 nanofibers with MoS2 nanoflakes anchoring on the core-shell C/C@SnO2 nanofibers through hydrothermal reaction. By adjusting the concentration of MoS2 precursors, the synthesized MoS2 with different slabs dimensions, size, and morphologies are obtained, constituting budding and blooming wintersweet branch-like composite structure, respectively. Owing to scattered MoS2 nanoparticles and sporadic MoS2 nanoflakes, the budding wintersweet branch-like composite nanofibers processes less slabs of staking in number and large specific surface area. Benefiting from the exposed C@SnO2 shell layer, the synergistic effect among SnO2, carbon, and MoS2 is strengthened, which maximizes the advantage of each material to exhibit stable specific capacities of 650 and 230 mAh g−1 for Li-ion batteries and Na-ion batteries after 200 cycles. [ABSTRACT FROM AUTHOR]

A facile synthesis of porous graphitic carbon nanofibers (CNFs) with encapsulated Co nanoparticles (denote as Co@CNFs) via electrospinning and subsequent annealing is reported. The in situ generated Co nanoparticles (NPs) promote the CNF graphitization under a low temperature of 700 °C, which simultaneously results in the porous structure of the Co@CNFs with a large surface area (416 m2 g−1). Furthermore, urchin-like CoSe2 nanorods are epitaxially grown from the Co@CNFs via a facile hydrothermal selenation, in which the embedded Co NPs serve as directing seeds and sacrificial Co-source, and CoSe2 nanorods are rooted into the CNFs (denote as CoSe2@CNFs). When used as anode materials for lithium ion batteries, the CoSe2@CNFs demonstrate superior lithium storage properties, delivering a high reversible capacity of 1405 mA h g−1 after 300 cycles at a current density of 200 mA g−1. The enhanced lithium storage performance can be attributed to the novel hybrid structure, namely, the porous and graphitic CNFs can not only facilitate the charge/ion transfer but also buffer the volume changes of the electrode during lithiation/delithiation processes. More importantly, a general strategy is provided to graphitize amorphous carbon materials via the use of in situ generated transition metal nanoparticles as catalyst. [ABSTRACT FROM AUTHOR]

Hybrid hollow urchin-like cobalt and copper silicate constructed by nanotubes encapsulated in graphene nanosheets composites were successfully prepared using graphene oxide as carrier and silica spheres as template, which were done through a well-known Stȍber process and a hydrothermal method. In fact, the synthesis of hybrid urchin-like silicate constructed by nanotubes through onestep hydrothermal reaction has rarely been reported.The electrochemical performances of the composites as lithium-ion battery anode materials were studiedfor the first time. As novel anode materials of Li-ion batteries, the special hollow urchin-like structure not only could facilitate the Li + diffusion and electron transport but alsocouldaccommodate the volume variation during the conversion reactions. In addition, the introduction of graphene can make the electrical conductivity better. Graphene wrapped hollow urchin-like silicate compositespossesses superior electrochemical cycling properties. The first discharge capacity is1955.2mAh/g with a current density of 300 mA/g. The unique well-designed configuration presents a beneficial method to synthesize efficient and high performance electrode materials for advanced power applications. [ABSTRACT FROM AUTHOR]

Carbon-coated SnO 2 composite nanofibers has been considered as an efficient way to alleviate the enormous volume change problem of tin-based anodes for lithium ion batteries (LIBs). Herein, porous carbon/SnO 2 nanofibers were prepared via single-needle electrospinning which was followed by carbonization treatment. The procedure involved two categories of precursors of SnO 2, stannic chloride pentahydrate and stannic acetate, whereas former was fully dissolved while later was partially dissolved in solvent, leading to different pore distribution in cooperating with thermal decomposition of polymethyl methacrylate. The pores generated from stannic chloride pentahydrate/polymethyl methacrylate system were randomly distributed on the surface of nanofibers. In the case of stannic acetate/polymethyl methacrylate derived composites, the thermolysis of polymer left multichannels within the nanofibers coupled with SnO 2 nanoparticles. Galvanostatic charge/discharge was carried out to evaluate them as anode materials for LIBs. It was found that multichannel carbon/SnO 2 nanofibers with large specific surface area (34.97 m 2 /g) achieved better rate capability and stable capacity retention of 89.9% after 50 cycles. The longitudinally aligned pores facilitated lithium diffusion and transference, which avoided nonuniform deposition and separation of lithium ions, thereby further enhancing the stability during the discharge/charge process. [ABSTRACT FROM AUTHOR]

Novel hierarchical flower-like Sn 3 O 4 assembled by thin Sn 3 O 4 nanosheets , as a kind of mixed-valence tin oxide, decorated on two-dimensional graphene nanosheets has been synthesized via a hydrothermal route and a step solution deoxidization technique. More importantly, as the anode materials for lithium ion batteries, the flower-like Sn 3 O 4 /graphene composite has not been investigated in detail. Noticeably, the nanosheets stemming from flower-like Sn 3 O 4 and graphene have been linked together to form a specials three dimensional structure, possessing high active surface area and large enough inner spaces, which is benefit to the diffusion of liquid electrolyte into the electrode materials. In addition, the special structure could provide sufficient free volume to buffer the volume expansion appeared in the process of discharging and charging. The as-prepared flowers-like Sn 3 O 4 /graphene displayed excellent electrochemical performance with high capacity and good cycling stability as anode materials for lithium ion batteries. The discharge capacity is 1727 mAh/g in the first cycle at the current density of 60 mA/g. The obtained reversible capacity is 631mAh/g with a coulomb efficiency of 97.04% after 50 cycles. With its better electrochemical properties, the as-prepared flowers-like Sn 3 O 4 /graphene has the potential to be the next generation materials as an environmentally benign, abundant, cheap anode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

A novel ordered Co/CMK-3 nanocomposite was successfully synthesized via the sonochemical method followed by carbonization process. The ordered Co/CMK-3 nanocomposite were characterized by X-ray diffraction, transmission electron microscopy and N 2 adsorption–desorption analysis techniques. The lithium storage properties shows that the Co/CMK-3 nanocomposites exhibit a large reversible capacity and good cycle stability with the capacity of 720 mAh g −1 after 50 cycles at a current rate of 50 mA g −1 , much higher than that of original CMK-3 electrode. The Co/CMK-3 nanocomposites also demonstrates an excellent rate capability with capacity of 479 mAh g −1 even at a current density of 1000 mA g −1 after 50 cycles. The improved lithium storage properties of ordered Co/CMK-3 nanocomposites can be attributed to the CMK-3 could restrain the aggregation of Co nanoparticles, the large surface area of the mesopores in which the Co nanoparticles are formed, as well as presence of Co which played the role of catalyst could promote the lithium storage reaction. [ABSTRACT FROM AUTHOR]

Transition metal oxides are said to have the ability to enhance the gravimetric capacity of lithium-ion batteries by two or three times that of current state-of-the-art graphite anodes. Recent reports have demonstrated that the combined utilization of structural architecture and surface modification is an attractive strategy to improve lithium storage capability. In this study, novel CuO-ZnO@Al 2 O 3 submicroflakes were prepared by magnetron sputtering deposition of Cu-Zn alloy films on a removable sacrificial substrate, followed by a facile thermal oxidation treatment and Al 2 O 3 coating procedure by particle atomic layer deposition. They combine the advantages of CuO-ZnO submicroflakes, such as high lithium storage capability and fast lithium ion transportation, and Al 2 O 3 nano-coating with effective protection of the electrode interface during cycling. When utilized as anode materials for LIBs, the CuO-ZnO@Al 2 O 3 submicroflakes exhibit superior specific capacity, enhanced cycling stability, and outstanding rate capability compared with pristine CuO-ZnO submicroflakes, commercial CuO and ZnO powders. The CuO-ZnO@Al 2 O 3 submicroflakes electrodes deliver a high reversible capacity of 814 mAh g−1 at a current density of 50 mA g−1, and still maintain a moderate capacity of 447 mAh g−1 at a high current density of 1000 mA g−1. Pairing with a commercial LiFePO 4 cathode, full cell shows high capacity retention and stable cycling performance, suggesting the feasibility of the CuO-ZnO@Al 2 O 3 submicroflakes in practical energy storage applications. In addition, our findings also provide a clear proof-of-concept of the surface coating technique, which might be applied widely to other materials and devices where nano-coating produces desirable properties. [Display omitted] • CuO-ZnO submicroflakes with Al 2 O 3 nano-coatings are fabricated for lithium-ion batteries. • The unique structural features endow fast ion transportation kinetics for charge storage. • The anodes possess high reversible capacity and remarkable rate capability. • The anodes exhibit long lifetime and stable cyclability in full cell measurements. [ABSTRACT FROM AUTHOR]

In order to overcome the poor electrical conductivity of titania (TiO2) and silica (SiO2) anode materials for lithium ion batteries (LIBs), we herein report a facile preparation of integrated titania–silica–carbon (TSC) nanofibers via electrospinning and subsequent heat-treatment. Both titania and silica are successfully embedded into the conductive N-doped carbon nanofibers, and they synergistically reinforce the overall strength of the TSC nanofibers after annealing (Note that titania–carbon or silica–carbon nanofibers cannot be obtained under the same condition). When applied as an anode for LIBs, the TSC nanofiber electrode shows superior cycle stability (502 mAh/g at 100 mA/g after 300 cycles) and high rate capability (572, 518, 421, 334, and 232 mAh/g each after 10 cycles at 100, 200, 500, 1000 and 2000 mA/g, respectively). Our results demonstrate that integration of titania/silica into N-doped carbon nanofibers greatly enhances the electrode conductivity and the overall structural stability of the TSC nanofibers upon repeated lithiation/delithiation cycling.

Novel a - MoO 3 nanorods coated with SnS 2 nanosheets core-shell nanorod composite has been synthesized via two hydrothermal routes. More importantly, as the anode materials for lithium ion batteries, the MoO 3 @SnS 2 core-shell nanorod composite has not been investigated in detail. The one-dimensional core-shell nanorod composite has high surface area, which could offer larger contact area for material and electrolyte. In addition, there are large enough inner spaces between the SnS 2 nanosheets, which provides an efficient transport of electrons and ions. In addition, the core-shell nanostructure could accommodate the volume changes caused by the charge/discharge reaction and could avoid the agglomerations and pulverization of anode materials.As anode materials for LIBs, the as-prepared MoO 3 @SnS 2 core-shell nanorod composite displayed 1663.2mAh/g discharge capacity in the first cycle at the current of 60mA/g. After 100 cycles, the remained capacity is 568.2mAh/g, which is both higher than that of a-MoO 3 and SnS 2 . Considering the excellent electrochemical performance with high capacity and good cycling stability, the as-prepared the MoO 3 @SnS 2 core-shell nanorod composite has the potential to be the next generation anode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Colloidal SnO 2 quantum dots (QDs) have been successfully prepared via a facile aqueous wet-chemical synthetic approach using tin dichloride as tin source and thiourea as accelerating and stabilizing agent under magnetic stirring at room temperature. The SnO 2 QDs with average size of ∼3.5 nm are well-dispersed in the aqueous solution with high stability. A facile ex-situ deposition of SnO 2 QDs on carbon nanotubes (CNTs) is developed, allowing large loading amount of SnO 2 QDs on the CNTs with uniform distribution. When used as anode material for lithium ion batteries, the as-prepared SnO 2 -CNT nanocomposites exhibit superior lithium storage properties, delivering a stable discharge capacity of 845 mAh/g at 100 mA/g after 90 cycles. More importantly, the novel synthetic strategy is promising for the cost-effective and large-scale fabrication of SnO 2 -CNT nanocomposites as high-performance anodes for electrochemical energy-storage. [ABSTRACT FROM AUTHOR]

To alleviate the enormous volume change problem of tin-based anodes for lithium ion batteries (LIBs), carbon-coated tin dioxide (SnO 2 ) hollow nanofibers were prepared by means of single-spinneret electrospinning followed by calcination and hydrothermal treatment. By varying the concentration of glucose and the reaction time during the hydrothermal coating process, the final product with different carbon distribution and thickness could be obtained. Galvanostatic charge/discharge was carried out to evaluate them as potential anode materials for LIBs. It was shown that the main effect of carbon distribution was to control the capacity retention rate, and the carbon thickness played the important role in lithium insertion/extraction properties. The optimum composite nanofibers could be prepared with glucose concentration of 10 mg/ml and hydrothermal time of 20 h, the carbon content and the specific surface area of which were 26.15% and 29.4 m 2 /g, respectively. And this anode with both the carbon core and deposited thin carbon skin was able to deliver a high reversible capacity of 704.6 mAhg −1 and the capacity retention could retain 68.2% after 80 cycles. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) reduced graphene oxide (RGO) frameworks confined hollow spherical SnO 2 -Fe 2 O 3 @RGO nano-shells (3D h-SnO 2 -Fe 2 O 3 @RGO) are successfully obtained by hydrothermal reduction of h-SnO 2 -Fe 2 O 3 @GO in graphene oxide (GO) suspension. As anode materials for lithium-ion batteries (LIBs), the novel 3D h-SnO 2 -Fe 2 O 3 @RGO architectures demonstrate great improvement in cycling performance (∼830 mAh g −1 after 100 cycles at 200 mA g −1 ) and rate capability (∼550 mAh g −1 at 1000 mA g −1 for 10 cycles) over that of hollow SnO 2 spheres (h-SnO 2 ), h-SnO 2 -Fe 2 O 3 , and 3D RGO frameworks wrapped hollow spherical SnO 2 @RGO nano-shells (3D h-SnO 2 @RGO). The 3D porous frameworks and coating graphene nano-shells serve as efficient electron and ion conductive networks as well as buffer for the large volume variation of hollow SnO 2 -Fe 2 O 3 during cycling. Moreover, the hollow spherical metal oxide mesoporous nano-shells could enlarge the surface area, retard the volume change, prevent aggregation of nanosized active materials and graphene nanosheets. [ABSTRACT FROM AUTHOR]

Nanosilicon@nonstoichiometric silicon oxide where nanosilicon is embedded in SiO x matrix (abbreviated as nano-Si@SiOx), is a very attractive material structure to suppress the volume effect of silicon in Lithium-ion batteries. In this work, we demonstrate that the combination of electrolysis and peeling technique produce nano-Si@SiOx from bulk SiO 2 . X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) are employed to characterize the prepared materials. The average O/Si atomic ratio of the synthesized nano-Si@SiOx is about 0.91. The nano-Si@SiOx/graphite composite prepared using it as the precursor exhibits a stable discharge capacity of about 1560 mAh g −1 (calculated on the total mass of the composite) with good cyclic stability and rate capability. This work provides a new routine to prepare nano-Si@SiOx composite. [ABSTRACT FROM AUTHOR]

The ultrasmall CoFe 2 O 4 nanoparticles in situ encapsulated in porous N-doped carbon nanofibers membranes (CFO@PNCFM) with different pore structures have been prepared by electrospinning and subsequent carbonization. When immediately used as self-standing anodes for lithium-ion batteries (LIBs), the optimized CFO@PNCFM exhibits superior lithium storage properties with high rate capability (476.5 mAh g−1 at 2 A g−1) and long stable cycle life (755.8 mAh g−1 at 100 mA g−1 after 200 cycles). The outstanding electrochemical performance may be mainly ascribed to the synergistic effect of special 3D conductive porous carbon nanofibers (PCNFs) network and ultrafine CoFe 2 O 4 nanoparticles in energy storage, which can significantly enhance the utilization efficiency of electroactive materials and improve the charge-transport kinetics. Moreover, the CoFe 2 O 4 nanoparticles bonded closely to PCNFs through strong metal-oxygen bridges, which promote the electron capture and transfer from PCNFs to CoFe 2 O 4 , and thus achieving fast electrochemical reaction kinetics. Meanwhile, the porous structure can not only alleviate the volume change during charge/discharge cycles, but also supply numerous active sites for lithium storage, resulting in a high reversible capacity as well as good cycle stability and rate performance. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) zinc vanadate (α-Zn 2 V 2 O 7 ) nanofibers have been synthesized through electrospinning combined with an annealing process. When used as anode material for lithium-ion batteries (LIBs), electrospun 1D α-Zn 2 V 2 O 7 nanofibers exhibit a reversible capacity of ∼708 mAh g −1 after 100 cycles at a current density of 50 mA g −1 . A good rate capability is also achieved even at higher current densities. When cycled at a current density of 2000 mA g −1 , the electrode can still show a reversible capacity of ∼311 mAh g −1 . The excellent cycle performance and rate capability may be due to the 1D nanofiber architectures, mesoporous structures, and relatively large specific surface area, which can provide a short ion diffusion path and continuous electron transportation. Therefore, this work presents a simple and efficient approach for fabrication of 1D α-Zn 2 V 2 O 7 nanofibers, which are promising high-performance anode materials for LIBs. [ABSTRACT FROM AUTHOR]

In this work, we successfully synthesize ordered Sn/CMK-3 nanocomposites by sonochemical method and carbonization process. XRD results verify that SnO 2 has been completely reduced to metal Sn for the samples obtained at 800 °C. Sn nanoparticles are good dispersed into the pore channels of ordered CMK-3 for Sn/CMK-3 nanocomposites according to the nitrogen adsorption–desorption isotherms. The lithium storage properties shows that the Sn/CMK-3 nanocomposites obtained at 800 °C delivers an initial discharge capacity of 1450 mAh g −1 , and a reversible capacity as high as 674 mAh g −1 after 50 cycles at a current density of 100 mA g −1 , much higher than those of the samples obtained at 600 °C (1352 and 411 mAh g −1 , respectively). The Sn/CMK-3 nanocomposites obtained at 800 °C also demonstrates an excellent rate capability with capacity of 546 mAh g −1 even at a current density of 1000 mA g −1 after 50 cycles. The improved lithium storage properties of Sn/CMK-3 nanocomposites obtained at 800 °C can be attributed to a synergistic reaction between Sn nanoparticles and CMK-3 matrix, as well as the high crystallinity. [ABSTRACT FROM AUTHOR]

In this study, we successfully synthesized magnesium ferrite (MgFe 2 O 4 ) nanofibers by a facile electrospinning technique followed by calcining at 800 °C. The lithium storage properties of MgFe 2 O 4 nanofibers as anode materials for lithium-ion batteries have been discussed for the first time. It is demonstrated that MgFe 2 O 4 nanofibers electrode not only deliver a high initial discharge capacity of around 1304 mAh g −1 , but also maintain a reversible capacity of 714 mAh g −1 after 100 cycles. Moreover, the MgFe 2 O 4 nanofibers electrode also exhibits high capacity at higher charge/discharge rate. Even at a current density of 2000 mA g −1 , the reversible capacity can attain 409 mAh g −1 after 100 cycles, suggesting its excellent rate capability. The superior lithium storage properties of the MgFe 2 O 4 nanofibers electrode may be related to the unique continuous fibrous morphologies, nanostructured architectures, porous structures, and large specific surface area, which provide an easily Li + diffusion path and promote electron transfer. In addition, the formation of MgO appears to act as a buffer layer that prevents agglomeration of nanocrystalline, accommodate the large volume change and reduces polarization during cycling. [ABSTRACT FROM AUTHOR]

A SnSb nanocrystal/graphene hybrid nanocomposite was synthesized by a facile one-step solvothermal route using graphite oxide, SnCl2.2H2O and SbCl3 as the starting materials, absolute ethanol as the solvent, and NaBH4 as the reductant. The formation of SnSb alloy and the reduction of the graphene oxide occur simultaneously. SnSb nanoparticles with a size of 30–40 nm were uniformly anchored and confined by the graphene sheets, forming a unique SnSb/graphene hybrid nanostructure. The electrostatic attraction between the positively charged ions (Sn2+ and Sb3+) and the negatively charged graphene oxide plays an important role in the uniform distribution of the SnSb particles on the graphene sheets. The electrochemical Li-storage properties of the nanocomposite were investigated as a potential high-capacity anode material for Li-ion batteries. The results show that the nanocomposite exhibits an obvious enhanced Li-storage performance compared with bare SnSb. The improvement of the electrochemical performance could be attributed to the formation of two-dimensional conductive networks, homogeneous dispersion and confinement of SnSb nanoparticles and the enhanced wetting of active material with the electrolyte for increased specific surface area by the introduction of graphene into SnSb nanoparticles. Li-ion chemical diffusion coefficient and ac impedance were measured to understand the underlying mechanism for the improved electrochemical performance. [ABSTRACT FROM AUTHOR]

• CNTs and N-doped carbon decoration can enhance electronic conductivity of Si-based anode. • CoSi 2 can improve the structural stability of Si-based anode. • The introduced Co can catalyze the graphitization of carbon shell. • The designed Si-based anode delivers enhanced electrochemical properties. [Display omitted] Silicon is evaluated as a competitive lithium-ion batteries anode material by virtue of its ultrahigh specific capacity and relatively low discharge potential. However, the large volume change during lithiation/delithiation processes, and the low intrinsic electric conductivity have seriously impeded its widespread practical application. Herein, silicon nanoparticles (SiNPs) coated with CNTs-intertwined N-doped porous carbon (NPC) are prepared via a facile solution-phase method, followed by thermal annealing treatment. In this hierarchical structure, the bimetallic ZIF-derived porous carbon can shorten the migration channels of Li+ and electrons. Moreover, the formed Co nanoparticles can not only catalyze the graphitization of carbon, but also propel in-situ growth of CNTs to constitute a 3D interconnected conductive network, thereby improving the electrochemical performance. Benefiting from the unique structure, the as-prepared Si@CoSi 2 /Co-NPC@CNTs electrode exhibits superior electrochemical performance of 1191 mAh g−1 at 0.5 A g−1 after 200 cycles. Meanwhile, the electrode also shows excellent rate capability of 930 mAh g−1 even at a high current density of 6 A g−1. This work provides a new strategy to design exceptionally high electrical conductivity and structure stability of Si-based anode materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • High specific surface area (SSA) (241.1 m2 g−1) with robust pores conductive composite nanofibers are prepared. • Superior capacity performance of 2048 and 1712 mAh g−1 for the 1st and after 500th cycles were achieved. • Stable structure with low volume expansion even after long cycling (500th) was presented. Volume expansion is one of the challenges of hindering the implementation of lithium-ion batteries (LIBs). In this respect, the RGO/NiCo 2 O 4 @carbon composite nanofibers (RGO/NCO@C) derived from metal-organic frameworks are developed by an effective in-situ growth, electrospinning and assisted procedure of calcination. The NiCo 2 O 4 particles anchor on the carbon nanofibers that decorated with the graphene sheets to form a bead-like structure, which endows the anode material with large specific surface area (SSA), massive pore structures and desirable mechanical strength. Benefiting from above excellent physical properties, the composite nanofibers greatly relief the volume expansion and efficiently shorten the Li-ion diffusion path. As a result, superior cyclability and great rate capability are obtained upon using as anode material for lithium-ion batteries. An extremely high reversible charge capacity of 2048 mAh g−1 is achieved in the first cycle, and capacity retention of 1712 mAh g−1 is retained after 500 cycles at 0.3 A g−1. Under various current densities ranging from 0.3 to 2 A g−1, the reversible capacity of 1783 mAh g−1 at 0.3 A g−1 is sustained. The proposed method and developed materials herein offer an effective strategy to overcoming the volume expansion and preparing electrode materials for high performance LIBs. [ABSTRACT FROM AUTHOR]

Si has been regarded as one of the most promising anodes for next-generation lithium ion batteries for its high theoretical capacity (3579 mA h g−1) and low operating potential of 0.4 V vs Li/Li+. However, the huge volume change during (de)lithiation and low electronic conductivity impede its further commercial applications. In this work, Zn/Si porous multi-layer films with controllable layer number (from 1 to 6 layers) are constructed firstly, and then a ZnO thin layer is sputtered on the top surface of the Zn/Si films to fabricate the Zn/Si/ZnO porous multi-layer films. When used as binder-free anodes, the designed 4 layers Zn/Si/ZnO thin film anode delivers the highest specific capacity, best cycling and rate performance than other multi-layer film anodes and the bulk Zn/Si/ZnO film anode with the same overall thickness. The excellent electrochemical properties of the prepared 4 layers Zn/Si/ZnO porous composite film anode can be attributed to its porous and multilayer structure, which can moderate the volume change, decrease the internal stress and benefit to the penetration of electrolyte. Moreover, the 3D electron and Li+ ion conductive channels resulted from the formed Li–Zn alloy during cycling can help to increase the electrochemical reaction kinetics. • Porous multilayer structure helps moderate the volume change of Si film anode. • Ion and electron conductive alloy framework increase the reaction kinetics. • The introduced Li 2 O layer helps to stabilize the electrode interface. [ABSTRACT FROM AUTHOR]

Transition metal oxide/reduced graphene oxide (TMO/RGO) composites have been explored for development as anode materials for lithium-ion batteries (LIBs); TMOs have high theoretical capacities, and the oxidation degrees of RGO sheets can directly affect the lithium storage performance of TMO/RGO composites. In this work, several NiO/reduced graphene oxide composites (NiO/RGO) are prepared based on oxidation degrees of graphite oxide sheets (GOs) through an ultrasonic agitation method. These composites are then explored as anodes for LIBs. Results show that the reversible capacity of NiO/RGO composites increases gradually to 1046 mA h/g and then declines to 956 mA h/g after 50 cycles at 100 mA/g. The variation rule of lithium storage properties of NiO/RGO samples can be attributed to the surface functional groups of RGO sheets, which can affect interfacial interaction between NiO and RGO sheets due to the different oxidation degrees of GO. Different RGO sheets also show distinct abilities to hinder NiO pulverisation and promote lithium-ion/electron diffusion during repeated charge and discharge processes. • Several NiO/RGO composites were produced using GO with different degrees of oxidation. • The lithium storage performances of the NiO/RGO electrodes first increased and then degraded due to functional group differences of different RGO sheets. • The NiO/RGO-5.5 composite delivered the highest reversible capacity of 402 mA h/g after 210 cycles at 3000 mA/g. [ABSTRACT FROM AUTHOR]

In order to overcome the poor electrical conductivity of titania (TiO2) and silica (SiO2) anode materials for lithium ion batteries (LIBs), we herein report a facile preparation of integrated titania–silica–carbon (TSC) nanofibers via electrospinning and subsequent heat-treatment. Both titania and silica are successfully embedded into the conductive N-doped carbon nanofibers, and they synergistically reinforce the overall strength of the TSC nanofibers after annealing (Note that titania–carbon or silica–carbon nanofibers cannot be obtained under the same condition). When applied as an anode for LIBs, the TSC nanofiber electrode shows superior cycle stability (502 mAh/g at 100 mA/g after 300 cycles) and high rate capability (572, 518, 421, 334, and 232 mAh/g each after 10 cycles at 100, 200, 500, 1000 and 2000 mA/g, respectively). Our results demonstrate that integration of titania/silica into N-doped carbon nanofibers greatly enhances the electrode conductivity and the overall structural stability of the TSC nanofibers upon repeated lithiation/delithiation cycling. [ABSTRACT FROM AUTHOR]

"Welcome-mat"-like porous Si/Cu composite amorphous films are fabricated by applying the predeposited Cu-nanoparticle-assembled film as the growth direction template for the subsequent deposition of a Si active layer with the cluster beam deposition technique. When used as the binder-free anodes for lithium ion batteries, the acquired single-layer porous Si/Cu composite film exhibits a large reversible capacity of 3124 mA h g -1 after 1000 cycles at 1 A g -1 . Even when cycled at 20 A g -1 for 450 cycles, the porous Si/Cu composite film still delivers a decent reversible capacity of 2086 mA h g -1 . Also, multilayer porous Si/Cu composite films are synthesized through layer-by-layer sputtering and exhibit outstanding cyclability and relatively high specific capacity and initial Coulombic efficiency irrespective of increasing the layer number from two to four layers. The reasons for the excellent electrochemical properties of single-layer and multilayer porous Si/Cu composite films are discussed in detail.

Herein, we introduce a facile electrostatic attraction approach to produce zinc-silver citrate hollow microspheres, followed by thermal heating treatment in argon to ingeniously synthesize sandwich-like Ag-C@ZnO-C@Ag-C hybrid hollow microspheres. The 3D carbon conductive framework in the hybrids derives from the in situ carbonation of carboxylate acid groups in zinc-silver citrate hollow microspheres during heating treatment, and the continuous and homogeneous Ag nanoparticles on the outer and inner surfaces of hybrid hollow microspheres endow the shells with the sandwiched configuration (Ag-C@ZnO-C@Ag-C). When applied as the anode materials for lithium ion batteries, the fabricated hybrid hollow microspheres with sandwich-like shells reveal a very large reversible capacity of 1670 mAh g(-1) after 200 cycles at a current density of 0.2 A g(-1). Even at the very large current densities of 1.6 and 10.0 A g(-1), the high specific capacities of about 1063 and 526 mAh g(-1) can be retained, respectively. The greatly enhanced electrochemical properties of Ag-C@ZnO-C@Ag-C hybrid microspheres are attributed to their special structural features such as the hollow structures, the sandwich-like shells, and the nanometer-sized building blocks.