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Highlights • A new hexagonal prisms CoO was assembled on reduced graphene oxide. • CoO in the composite is pure purity. • The composite performed high capacity as anode materials of lithium ion batteries. Abstract In this research, we use a modified sol-gel method to obtain a pure phase new hexagonal CoO on reduced graphene oxide by leading of polar solvent. In the electrochemical test, the CoO/rGO composite shows a remarkable performance of capacity as an anode of a lithium ion battery. The electrochemistry performance shows that the capacity of the composite can remain at 1300 mAh/g in 100 cycles without damping. The pure phase of CoO and its hexagonal morphology have been characterized by XRD, SEM and TEM. [ABSTRACT FROM AUTHOR]

The charge/discharge mechanism and electrochemical performance of Zn 3 V 3 O 8 as anode for Li-ion batteries are systematically studied. Theoretical calculation predicts that Zn 3 V 3 O 8 can act as a host for Li storage, and a possible diffusion way of Li-ions within the crystal structure is calculated via first principle methods. Experimentally, Zn 3 V 3 O 8 nanosheets with porous architecture are fabricated via a facile hydrothermal pretreatment and subsequent sintering. The Zn 3 V 3 O 8 shows superior electrochemical performance with graphite electric additive, exhibiting discharge/charge capacity of 541/537 mAh g −1 after 200 cycles at a specific current of 120 mA g −1 . The Li-storage mechanism is also studied via ex-situ XRD, and the maintenance of main diffraction peaks during lithiation/delithiation process suggests a possible intercalation/extraction mechanism of the Zn 3 V 3 O 8 . [ABSTRACT FROM AUTHOR]

Silicon (Si) is promising for high capacity anodes in lithium‐ion batteries due to its high theoretical capacity, low working potential, and natural abundance. However, there are two main drawbacks that impede its further practical applications. One is the huge volume expansion generating during lithiation and delithiation progresses, which leads to severe structural pulverization and subsequently rapid capacity fading of the electrode. The other is the relatively low intrinsic electronic conductivity, therefore, seriously impacting the rate performance. In the past decades, numerous efforts have been devoted for improving the cycling stability and rate capability by rational designs of different nanostructures of Si materials and incorporations with some conductive agents. In this review, the authors summarize the exciting recent research works and focus on not only the synthesis techniques, but also the composition strategies of silicon nanostructures. The advantages and disadvantages of the nanostructures as well as the perspective of this research field are also discussed. We aim to give some reference for engineering application on Si anodes in lithium ion batteries. [ABSTRACT FROM AUTHOR]

Chromium nitride (CrN) synthesized by heating at 550 °C under a continuous stream of ammonia has been investigated as anode material for lithium electrochemistry. Due to its low lithium insertion potential, Cr is an attractive material for lithium–ion battery application, but the usual volume variation effect obstructs its practical use. In this study, different concentrations of carbon nanotubes doped with nitrogen (NCNTs) are combined with CrN to attain high electrochemical performance. The synthesized CrN/0.08%–NCNTs nanocomposite demonstrates network structure with 30–40 nm CrN nanoparticles anchored to specific sites on 40–60 nm diameter NCNTs. Upon electrochemical testing, CrN/0.08%–NCNTs nanocomposite displays a discharge capacity of 1172 mAh g −1 after 200 cycles with high coulombic efficiency (∼100%) and rate capability. The electrode can deliver a reversible capacity of 1042.9 mAh g −1 at 20 C. The n-type concentration, along with the conductive CNTs framework, mesoporous channels, appropriate surface area and buffering capability of CNTs, are together responsible for the excellent electrochemical performance. The electrochemical reaction mechanism of CrN with lithium is explored by investigating the structural changes using ex situ X-ray photoelectron spectroscopy, X-ray diffraction, selected area electron diffraction, and high-resolution transmission electron microscopy. The reversible conversion reaction of CrN into Cr metal and Li 3 N is revealed. [ABSTRACT FROM AUTHOR]

A systematic study to reveal the relationship between the surface oxygen-containing functionalities of sub-10-nm GNRs and their electrochemical properties for lithium-ion batteries has been presented. Sub-10-nm GNRs with controlled oxygen-containing groups were synthesized by a green and scalable intercalation-assisted unzipping SWCNTs. Detailed materials characterizations including TEM, XRD, Raman and XPS indicate that KNO 3 could be an effective intercalation agent to facilitate the SWCNT unzipping by reducing the strong Van der Waals force attraction of bundled SWCNT. The levels of surface functionalities of sub-10-nm GNR were tuned by carefully controlling the KMnO 4 concentration during the unzipping process. The electrochemical analysis suggests that the as-produced sub-10-nm GNR with 31.4 atomic percent (atom %) oxygen-containing functional groups showed the highest capacity of 490.4 mAh g −1 after 100 cycles. This work proposed that sub-10-nm GNRs with appropriate oxygen-functional groups can be a promising electrode material for high performance lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Zero-dimensional quantum dots (QDs) are desired to enhance electrochemical response in energy storage. Here, we successfully synthesize well-dispersed and ultrafine TiO 2 -QDs, which are in situ embedded into the three-dimensional porous graphene-like networks (denoted as TiO 2 -QDs-3D GNs) via a simple low-temperature mixed solvothermal method, aiming at a fast electrochemistry with high-efficient electron and ion transport for lithium ion battery (LIB) anodes. By combining the advantages of the porous 3D GNs and ultrafine TiO 2 -QDs, the as-prepared TiO 2 -QDs-3D GNs hybrid electrode exhibits a high reversible capacity of 219 mA h g −1 after 100 cycles at 0.1 A g −1 , accompanied with an ultrahigh-rate capability of 121 mA h g −1 and a super-long lifespan of 3000 cycles with ∼82.0% capacity retention at 10 A g −1 . Detailed electrochemical analysis reveals that the superior rate capability and cycle performance are the main results of the integrated intercalation-based and interfacial lithium storage as well as the 3D fast electron/ion transfer of materials, which is attributed to the ultra-small size and high surface-to-volume ratio of TiO 2 -QDs as well as the 3D conducting networks of the integrated hybrid electrode. This study demonstrates the distinct advantages of our material design strategy, making it promising for the fast and ultralong-life anodes in LIBs. [ABSTRACT FROM AUTHOR]

The composite of Co 3 O 4 , Co and graphitized carbon is synthesized by carbonization and cobalt-catalyzed-graphitization of carboxymethyl chitosan, followed by low-temperature thermal oxidation. At the high temperature, the Co(+2) is reduced to metallic Co and the produced Co acts as a catalyst for the graphitization of the pyrolytic carbon. The low-temperature oxidation is conducted to selectively oxidize Co to Co 3 O 4 while the carbon remains unreacted. The structure analysis indicates that three crystal phases (graphite, metallic Co, Co 3 O 4 ) accompanied with amorphous carbon are co-existed in the composite. Morphological results demonstrate that a lot of graphite grains around the Co element are distributed in the carbon. The electrochemical testing results indicate that the composite shows good electrochemical performance. It delivers a reversible capacity of 843 mAh g −1 at low current density, and remains 88.9% after 60 cycles at 200 mA g −1 . Even performed at 1 A g −1 , it also exhibits 493 mAh g −1 . The performance improvement is mainly due to the high capacity of Co 3 O 4 , high conductivity of graphitic carbon and metallic cobalt, the porous structure offering enough ion transport pathways and relieving the strain during cycling. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide/Mn 3 O 4 (RGO/Mn 3 O 4 ) nanocomposites were synthesized via a cost-effective approach, and their microstructural and morphological features were investigated. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results revealed that the Mn 3 O 4 nanoparticles were crystallized with particle size 50–100 nm while the size of the Mn 3 O 4 particles in RGO/Mn 3 O 4 composites decreased to 30–50 nm, suggesting that RGO promoted the dispersion of Mn 3 O 4 particles. We tested the electrochemical behavior of the RGO/Mn 3 O 4 composites for supercapacitor and Li-ion battery. And it was found that they exhibited an excellent discharge specific capacitance of about 194.8 F/g at 1.0 A/g with 90% capacity retention even after 1000 cycles in supercapacitor, and an initial discharge capacity of about 1813 mAh/g at 0.1 A/g with outstanding cycling stability in Li-ion battery. [ABSTRACT FROM AUTHOR]

Temperature dependent fabrication of NiCr 2 O 4 is studied and the application of the as-prepared NiCr 2 O 4 in both half-cell with Li metal anode and full-cell with LiFePO 4 cathode are assessed. When mixing with natural graphite (NG), the NiCr 2 O 4 obtained at 550 °C can deliver initial charge and discharge capacities of 795 and 1275.5 mAh g −1 at a specific current of 150 mA g −1 , maintaining of 939 and 955 mAh g −1 after 140 cycles. In contrast, after 140 cycles at the same specific current, the NiCr 2 O 4 obtained at 450 °C and 650 °C can maintain charge/discharge capacities of 800/814 and 523/528 mAh g −1 , respectively. When matching with a LiFePO 4 cathode, The NiCr 2 O 4 /NG (obtained at 550 °C) electrode delivers initial discharge capacity of 285 mAh g −1 , which maintains of 106 mAh g −1 after 50 cycles at a specific current of 100 mA g −1 . [ABSTRACT FROM AUTHOR]

Core-shell nano-ring α-Fe 2 O 3 @Carbon (CSNR) composites with different carbon content (CSNR-5%C and CSNR-13%C) are synthesized using a hydrothermal method by controlling different amounts of glucose and α-Fe 2 O 3 nano-rings with further annealing. The CSNR electrodes exhibit much improved specific capacity, cycling stability and rate capability compared with that of bare nano-ring α-Fe 2 O 3 (BNR), which is attributed to the core-shell nano-ring structure of CSNR. The carbon shell in the inner and outer surface of CSNR composite can increase electron conductivity of the electrode and inhibit the volume change of α-Fe 2 O 3 during discharge/charge processes, and the nano-ring structure of CSNR can buffer the volume change too. The CSNR-5%C electrode shows super high initial discharge/charge capacities of 1570/1220 mAh g −1 and retains 920/897 mAh g −1 after 200 cycles at 500 mA g −1 (0.5C). Even at 2000 mA g −1 (2C), the electrode delivers the initial capacities of 1400/900 mAh g −1 , and still maintains 630/610 mAh g −1 after 200 cycles. The core-shell nano-rings opened during cycling and rebuilt a new flower-like structure consisting of α-Fe 2 O 3 @Carbon nano-sheets. The space among the nano-sheet networks can further buffer the volume expansion of α-Fe 2 O 3 and facilitate the transportation of electrons and Li + ions during the charge/discharge processes, which increases the capacity and rate capability of the electrode. It is the first time that the evolution of core-shell α-Fe 2 O 3 @Carbon changing to flower-like networks during lithiation/de-lithiation has been reported. [ABSTRACT FROM AUTHOR]

A novel air-stable titanium hexacyanoferrate (Ti 0.75 Fe 0.25 [Fe(CN) 6 ] 0.96 ·1.9H 2 O) with a cubic structure is synthesized simply by a solution precipitation method, which is first demonstrated to be a scalable, low-cost anode material for lithium-ion batteries exhibiting high capacity, long cycle life and good rate capability. Nevertheless, it has a low capacity of about 100 mAh g −1 as an anode material for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Manganese dioxide/cabon nanotubes (MnO 2 /CNTs) composites with tunable density of MnO 2 nanosheets on the surface of CNTs were synthesized by a facile room temperature solution method. When applied in lithium-ion batteries (LIBs) as anode materials, the spacial density of MnO 2 nanosheets in the MnO 2 /CNT composite was verified to be crucial for the lithium storage performance. The optimized composite with moderate spatial density of MnO 2 nanosheets delivered a reversible capacity of 903 mA h g −1 at the current rate of 0.24 A g −1 . Moreover, this composite exhibited a high stable capacity of 540 mA h g −1 even at a high current density of 2.4 A g −1 after 1500 cycles, demonstrating its potential for applications in LIBs with long cycling life and high power density. The enhanced electrochemical performance of the optimized composite was ascribed to sufficient space between the MnO 2 nanosheets on the CNTs, which not only allows the effective electrical contact between the CNT backbones and the conductive carbon but also accommodates the large volume changes upon repeated lithiation/delithiation. [ABSTRACT FROM AUTHOR]

Customized hierarchical porous metal oxide arrays is of great importance for construction of high-performance electrochemical devices. In this work, we report hierarchical porous (HP)-NiO sheets arrays by a facile hydrothermal method. Interestingly, the obtained NiO sheets arrays show HP systems, and are composed of cat-ear-like sheets main structure and interconnected nanosheets secondary structure. Moreover, the secondary nanosheets are highly porous and consist of cross-linked nanoparticles of 30–100 nm. The electrochemical performances of the HP-NiO sheets arrays are evaluated as anode for Li ion batteries. Compared with the normal NiO sheets arrays, enhanced electrochemical performances are achieved for the HP-NiO sheets, including higher capacity, better cycling life and high-rate capability. The HP-NiO sheets can deliver a specific capacity of 511 mAh g −1 at 3 A g −1 , higher than the normal NiO sheets arrays (374 mAh g −1 at 3 A g −1 ), due to the hierarchical porous array configuration with large surface area, fast ion diffusion path and better accommodation of volume change. [ABSTRACT FROM AUTHOR]

NiCr 2 O 4 is successfully prepared via hydrothermal pretreatment and subsequent sintering, which shows excellent electrochemical performance as a new anode material for lithium ion batteries with natural graphite adding and sodium alginate binder. At a specific current of 70 mA g −1 , it delivers charge and discharge capacities of 465.5 and 919.8 mAh g −1 in the initial cycle, which gradually increases along with cycle number owing to an electrochemical reconstruction in cycling. After 100 cycles, the charge and discharge capacities are 582.9 and 592.5 mAh g −1 , respectively. Furthermore, it is testified that natural graphite adding can effectively improve the electronic conductivity of the NiCr 2 O 4 electrode, and an appropriate amount of natural graphite is beneficial to improve the specific capacity and cycle stability of the electrode owing to a coordinated electrochemical reconstruction between NiCr 2 O 4 and natural graphite in cycling. [ABSTRACT FROM AUTHOR]

We report a simple microwave-assisted method to fabricate high-quality two-dimensional (2D) ultrathin NiCo 2 O 4 nanosheets with a geometrically graphene-like architecture. The unique large-area nanostructures represent an ultrahigh surface atomic ratio with almost all active elements exposed outside for surface-dependent electrochemical reaction processes. Experimental results reveal that the as-synthesized ultrathin NiCo 2 O 4 nanosheets show excellent electrochemical performances for lithium storage application. The ultrathin NiCo 2 O 4 nanosheets could deliver a high first discharge capacity (1287.1 mAh g −1 ) with initial Coulombic efficiency of 80.0% at 200 mA g −1 current density. The reversible lithium storage capacity still retains at 804.8 mAh g −1 in the 100th cycle, suggesting a good cycling stability. The excellent electrochemical properties of the as-synthesized NiCo 2 O 4 nanosheets could be ascribed to the unique ultrathin 2D architecture, which could offer large exposed active surface with more lithium-insertion channels and significantly reduce lithium ion diffusion distance. The cost-efficient synthesis and excellent lithium storage properties make the 2D NiCo 2 O 4 nanosheets as a promising anode material for high-performance lithium ion batteries. [ABSTRACT FROM AUTHOR]

CoV 2 O 6 /natural graphite electrode with sodium alginate binder is prepared, which shows excellent electrochemical performance as anode for Li-ion batteries. It exhibits initial discharge and charge capacity of 902 and 638 mAh g −1 at a specific current of 110 mA g −1 . After 100 cycles, the discharge and charge capacity maintain of 669 and 665 mAh g −1 , respectively. The charge/discharge mechanism of CoV 2 O 6 is also studied, suggesting a structure variation in discharging, which involves the initial formation of LiV 2 O 5 and Co 3 V 2 O 8 , the subsequent transition from Co 3 V 2 O 8 to Li x V 2 O 5 and CoO, and the later reduction of CoO into Co. The structure variation of Co 3 V 2 O 8 accompanies by an amorphization process, which maintains in the subsequent discharging and charging process. [ABSTRACT FROM AUTHOR]

Li 3 VO 4 nanoparticles with mean size about 100 nm are uniformly deposited on the surface of natural graphite via a quasi sol gel method. The electrochemical performance of the Li 3 VO 4 /natural graphite composite as anode for lithium ion batteries is studied via galvanostatic battery testing, which shows excellent cycle stability and rate capability. At a specific current of 156 mA g −1 , it delivers discharge and charge capacity of 579 and 427 mAh g −1 in the initial cycle, which maintain of 469 and 468 mAh g −1 after 100 cycles. After 60 cycles at various specific currents from 234 to 11,719 mA g −1 , the discharge capacity can restore to 450 mAh g −1 when reverting the discharge/charge current to 234 mA g −1 . It is demonstrated that natural graphite has important effect on the electrochemcial performance of the composite electrode, and an appropriate amount of natural graphite is beneficial to reduce the charge transfer resistance and maintain stable charge transfer process in cycling. [ABSTRACT FROM AUTHOR]

Abstract: Fe2O3-graphite (Fe2O3-G) composites have been facilely and effectively synthesized via ball milling. Structural features and electrochemical properties of the Fe2O3-G composites as anodes for lithium-ion batteries are investigated. The Fe2O3-G composites benefit from the close contact of nanocrystalline Fe2O3 with the graphite matrix, which improves the electronic conductivity and restrains the volume variation during cycling. The composite with 20% graphite shows the highest reversible capacity up to 491.1 mAh g−1 after 55 cycles with good rate capability. Due to the superior electrochemical performance, the Fe2O3-G composites prepared via ball milling could be promising as anode materials with high capacity, low-cost for lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: Uniform Fe3O4/PPy composite nanospheres (FPCNs) with Fe3O4 nanoparticles embedded in PPy nanospheres (∼200nm) were prepared by a hydrothermal process followed by an ultrasonication assisted polymerization. For the first time, FPCNs were used as anode for lithium ion batteries, demonstrating enhanced electrochemical performance with high reversible capacity (544mAhg−1 after 300 cycles), remarkable capacity retention (98% of the initial capacity after 300 cycles), as well as good rate capability (332 mAh g−1 at 2000mAg−1). The spherical PPy matrix in FPCNs possesses three functions: 1) buffering the structural variation of Fe3O4 nanoparticles during charging/discharging process; 2) preventing the aggregation of Fe3O4 nanoparticles; 3) avoiding the direct contact between Fe3O4 nanoparticles and the electrolyte. The results observed in this study may shed some light on the investigation of MOx/polymer composite electrode materials. [Copyright &y& Elsevier]

Abstract: Undoped and 2 wt% vanadium (V5+) doped TiO2 samples are prepared in polyol medium by low-temperature solvothermal method. The as-prepared samples are annealed at 400 °C for 5 h in an air atmosphere to increase the crystallinity. The XRD pattern shows that pure anatase TiO2 is formed in both the doped and undoped samples. The maximum sizes of nanoparticles are found to be 300 nm and 15 nm with spherical shaped morphology for undoped TiO2 and V5+ doped TiO2 samples respectively. In addition, 2 wt% V5+ doped sample exhibits excellent electrochemical performance with high reversible specific capacity and excellent rate capability compared to the undoped case. This improvement can be attributed to the substitution of the Ti4+ ions by V5+ ions in the TiO2 lattice and create more Ti4+ vacancies in the lattice. This action may lead to the generation of apparently more number of free holes in the doped p-type semiconductor. Therefore, the increased hole concentration in the valence band can contribute to the electrical conductivity of the doped sample. Vanadium doping also influences the sample crystallinity and reduces the particle size, which provides a larger active surface area than that of undoped TiO2. [Copyright &y& Elsevier]

Highlights: [•] Facile, fast and low-cost urea synthesis of porous SnO2 anode for lithium ion battery. [•] Porous SnO2 anode delivers excellent electrochemical performances. [•] High surface area, good electric contact and easier Li+ diffusion give high performances. [•] Finer the sizes of the SnO2 nanoparticles better the cycling stability. [ABSTRACT FROM AUTHOR]

Highlights: [•] Polymer-derived SiCN and SiOC ceramics are studied as anode for Li-ion batteries. [•] Ceramic precursors are modified in order to increase the carbon content. [•] Ceramic matrix stabilizes free carbon phase. [•] Stabilizing role is lost once the amount of carbon exceeds a threshold value. [Copyright &y& Elsevier]

Abstract: A novel C/Co composite with Co nanoparticles embedded in carbon matrix is synthesized firstly by pyrolysis of polymeric cobalt phthalocyanine (PcCo) at 700°C in argon atmosphere. This composite is investigated as an anode material for lithium ion batteries, indicating high tap density and excellent electrochemical performance. The C/Co electrode can retain a higher reversible capacity of over 600mAhg−1 at a current of 50mAg−1 after 40cycles and shows better rate capability and less hysteresis in comparison to carbon not containing Co. The significant improvement is attributed to the Co nanoparticles grown in-situ reaction with catalytic activity and high electrical conductivity. [Copyright &y& Elsevier]

Abstract: We report here a polymer-templated hydrothermal growth method and subsequent calcination to achieve carbon coated hollow CuFe2O4 spheres (H–CuFe2O4@C). This material, when used as anode for Li-ion battery, retains a high specific capacity of 550mAhg−1 even after the 70th cycle, which is much higher than those of both CuFe2O4@C (∼300mAhg−1) and H–CuFe2O4 (∼120mAhg−1). And galvanostatic cycling at different current densities reveals that a capacity of 480mAhg−1, 91% recovery of the specific capacity cycling at 100mAg−1, can be obtained even after 50 cycles running from 100 to 1600mAg−1. The significantly enhanced electrochemical performances of H–CuFe2O4@C with regard to Li-ion storage are ascribed to the following factors: (1) the hollow void, which could mitigate the pulverization of electrode and facilitate the lithium-ion, electron and electrolyte transport; (2) the conductive carbon coating, which could enhance the conductivity, alleviate the agglomeration problem, prevent the formation of an overly thick SEI film and buffer the electrode. Such a structural motif of H–CuFe2O4@C is promising, for electrode materials of LIBs, and points out a general strategy for creating other hollow-shell electrode materials with improved electrochemical performances. [Copyright &y& Elsevier]

Abstract: A unique ordered mesoporous Sn–C composite with Sn nanoparticles confined in carbon nanorods was prepared using SBA-15 as the template. This composite was employed as the anode material of Li-ion batteries, delivering excellent electrochemical properties of high reversible lithium storage capacity (554 mAh g−1 after 200 cycles) and great rate capability (as high as 5000mA g−1). [Copyright &y& Elsevier]

Abstract: CuO/C microspheres are prepared by calcining CuCl2/resorcinol-formaldehyde (RF) gel in argon atmosphere followed by a subsequent oxidation process using H2O2 solution. The microstructure and morphology of materials are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transition electron microscopy (TEM). Carbon microspheres have an average diameter of about 2μm, and CuO particles with the sizes of 50–200nm disperse in these microspheres. The electrochemical properties of CuO/C microspheres as anode materials for lithium ion batteries are investigated by galvanostatic discharge–charge and cyclic voltammetry (CV) tests. The results show that CuO/C microspheres deliver discharge and charge capacities of 470 and 440mAhg−1 after 50 cycles, and they also exhibit better rate capability than that of pure CuO. It is believed that the carbon microspheres play an important role in their electrochemical properties. [Copyright &y& Elsevier]

Abstract: Thermodynamic calculation and kinetic analysis were performed on the carbothermal reduction process of Co3O4–Sb2O3–C system to clarify the reaction mechanism and synthesize pure CoSb powder for the anode material of secondary lithium-ion batteries. The addition of carbon amount and thus the purity of CoSb powders were critical to the electrochemical property of CoSb anode. It was revealed that in an inert atmosphere, Co3O4 was preferentially reduced to CoO, followed by the reduction of Sb2O3 and CoO. CO2 was the gas product for the reduction of Co3O4 and Sb2O3, while CO was the gas product for that of CoO. Based on the analysis result, pure CoSb powder without any oxides and residual carbon was synthesized, which showed a higher specific capacity and a lower initial irreversible capacity loss, compared to CoSb sample with residual carbon. This work can be a reference for other carbothermal reduction systems. [Copyright &y& Elsevier]

Abstract: The macroporous SnO2 is prepared using close packed carbonaceous sphere template which synthesized from glucose by hydrothermal method. The structure and morphology of the macroporous SnO2 are evaluated by XRD and FE-SEM. The average pore size of the macroporous SnO2 is about 190nm and its wall thickness is less than 10nm. When the macroporous SnO2 filled with carbon is used as an anode material for lithium-ion battery, the capacity is about 380mAhg−1 after 70 cycles. The improved cyclability is attributed to the carbon matrix which is used as an effective physical buffer to prevent the collapse of the well dispersed macroporous SnO2. [Copyright &y& Elsevier]

Abstract: Although a variety of cathode and electrolyte materials have been studied and commercialized over the past two decades, nearly all commercial cells have used a graphitic carbon anode. Several reasons exist for this choice—including cost, low insertion voltage, and ease of use in the cell manufacturing process. However as uses for lithium-ion batteries expand, alternative anodes that may offer better energy and power capability are being explored. For transportation-oriented purposes, anodes based on simple lithiated Zintl compounds, e.g. Li17Sn4, or intermetallic insertion anodes offer significant advantages in capacity (volumetric and gravimetric) and stability in the cell environment that make them attractive candidates for future cell chemistries. Within this context, little however is known about how these alternative anode materials perform as a function of temperature, which is important for applications where operation at temperatures as low as −30°C can be expected. In this study we evaluated a series of intermetallic insertion anodes that operate by a simple metal displacement mechanism. We have found that for Cu6Sn5, Ag/Cu6Sn5, and Cu2Sb, the drop-off in performance with temperature is in line with that observed for a commercial graphite-based anode and indicates that additional variables such as cation diffusion through the electrode passivation film or the electrochemical double layer may be playing an important role that is independent of the underlying anode material. We additionally characterized the NiAs-type mineral Sorosite (CuSn0.9Sb0.1), as various literature reports had indicated that substitution of antimony for tin eliminated the need for interstitial copper, however powder X-ray diffraction studies of samples made by annealing or high energy ball milling indicated mixed phase samples. [Copyright &y& Elsevier]

Abstract: NiO/Co–P nanocomposite is prepared by an electroless cobalt plating technique. The as-prepared composite is characterized by means of X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. SEM and TEM images reveal that the NiO particles are about 200nm in size, which are modified by Co–P nanoparticles of about 30nm. The electrochemical properties as anode materials for lithium ion batteries are examined by cyclic voltammetry (CV) and discharge–charge tests. The results show that, compared with the bare NiO without electroless cobalt plating, NiO/Co–P nanocomposite exhibits a smaller polarization and a better rate capability, which is attributed to the Co–P nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: Highly ordered porous Ni3P film was successfully electrodeposited through a self-assembled monodisperse polystyrene sphere template on copper substrate after heat treatment. The spherical pores left in the film after the removal of polystyrene spheres are well-ordered and close-packed. The diameter of the pores arranged in the film is about 800nm and the thickness of the wall connecting adjacent pores is 60nm. As anode for lithium ion batteries, the nanostructured porous Ni3P film exhibits improved capability and reversibility over the dense one. After 50 cycles, the reversible capacity of the porous Ni3P film is 403mAhg−1 and 239mAhg−1 at 0.2C and 2C, maintaining 78.1% and 67.9% of the capacity in the 2nd cycle, respectively. The enhanced electrochemical performance of the porous film is attributed to the better contact between Ni3P and electrolyte, which provides more sites for Li+ accommodation, shortens the diffusion length of Li+ and enhances the kinetics of electrode process. Moreover, the porous structure is stable and can sustain well even after 50 cycles. [ABSTRACT FROM AUTHOR]

Abstract: Porous nickel phosphide films are fabricated by electrodeposition through self-assembled polystyrene sphere multi-layers as template. After the removal of the template, well-ordered and close-packed spherical pores are left in the films. The thin walls of the adjacent pores make up a three-dimensional network nanostructure in the triple-layer porous Ni3P film. The as-prepared triple-layer porous film delivers significantly enhanced rate capability over the single- and double-layer ones. After 50 cycles, the capacity of the triple-layer Ni3P porous film still sustains 557mAhg−1 and 243mAhg−1 at a charge–discharge rate of 0.2C and 5C (1 C=388mAg−1), respectively. According to the analysis of electrochemical impedance spectrum (EIS), the improved electrochemical performance of the triple-layer film can be attributed to the fast migration of Li+ through surface-passivating layer and the facilitated charge transfer into Ni3P three-dimensional network nanostructure. [ABSTRACT FROM AUTHOR]

Abstract: Nano-sized Co–Sn alloys with a certain amount of Sn oxides used as potential anode materials for lithium ion batteries were synthesized by hydrothermal route. The effects of hydrothermal conditions and post annealing on the phase compositions and the electrochemical properties of synthesized powders were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) with energy dispersive spectra (EDS) analysis and galvanostatic cycling tests. Prolonging the dwelling time at the same hydrothermal temperature can increase the content of Sn oxides, which will lead to a high initial irreversible capacity loss but a better cycling stability owing to the buffer effect of irreversible product Li2O. Heat-treatment can increase the crystallinity and cause the presence of a certain amount of inert CoSn component, which both have positive impact on the cycling stability of Co–Sn electrode. By comparison with the lithiation/delithiation processes of metal Sn, a two-step mechanism of CoSn2 alloy during cycling was confirmed. [ABSTRACT FROM AUTHOR]

Abstract: NiO/poly(3,4-ethylenedioxythiophene) (PEDOT) films are prepared by chemical bath deposition and electrodeposition techniques using nickel foam as the substrate. These composite films are porous, and constructed by many interconnected nanoflakes. As anode materials for lithium ion batteries, the NiO/PEDOT films exhibit weaker polarization and better cycling performance as compared to the bare NiO film. Among these composite films, the NiO/PEDOT film deposited after 2 CV cycles has the best cycling performance, and its specific capacity after 50 cycles at the current density of 2C is 520mAhg−1. The improvements of these electrochemical properties are attributed to the PEDOT, a highly conductive polymer, which covers on the surfaces of the NiO nanoflakes, forming a conductive network and thus enhances the electrical conduction of the electrode. [Copyright &y& Elsevier]

Abstract: NiO films were prepared by chemical bath deposition and electrodeposition method, respectively, using nickel foam as the substrate. The films were characterized by scanning electron microscopy (SEM) and the images showed that their morphologies were distinct. The NiO film prepared by chemical bath deposition was highly porous, while the film prepared by electrodeposition was dense, and both of their thickness was about 1μm. As anode materials for lithium ion batteries, the porous NiO film prepared by chemical bath deposition exhibited higher coulombic efficiency and weaker polarization and its specific capacity after 50 cycles was 490mAhg−1 at the discharge–charge current density of 0.5Ag−1, and 350mAhg−1 at 1.5Ag−1, higher than the electrodeposited film (230mAhg−1 at 0.5Ag−1, and 170mAhg−1 at 1.5Ag−1). The better electrochemical performances of the film prepared by chemical bath deposition are attributed to its highly porous morphology, which shorted diffusion length of lithium ions, and relaxed the volume change caused by the reaction between NiO and Li+. [Copyright &y& Elsevier]

Abstract: Nanosized silver particles were uniformly distributed on the surface of silicon particles by electroless deposition (ED) and high-energy mechanical milling (HEMM) methods, respectively. The HEMM-prepared Si/Ag composite with 10 wt.% silver exhibited a high first coulombic efficiency of 83.4% and a large capacity of ca. 800 mA h g−1 over 30 cycles as a result of conductivity enhancement. It was suggested that electric contact between silicon particles played a significant role in improving the cyclability of silicon electrode. [Copyright &y& Elsevier]

Cu3P is studied as a potential material to be used as anode in a Li-ion battery. Depending on the synthetic route, solvothermal, ball-milling (with or without annealing), spray method or ceramic, used for its preparation, Cu3P shows various particle sizes and crystallinities. The electrochemical reactivity towards lithium of these various Cu3P powders is discussed through galvanostatic and potentiodynamic measurements, electron microscopy techniques, and X-ray diffraction on powder. Electrochemical performances, especially initial capacity and capacity retention, are shown to strongly correlate to the powder morphologies: small particle size favors high capacity values and the operation scan rate affects the capacity depending on the degree of crystallinity of the powder. On other hand, the battery capacity retention is better with microsized powders. [Copyright &y& Elsevier]