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Abstract This work explores the compound Li 1+z/3 Ni 1/2-z/2 Ti 1/2+z/6 O 2 (z = 0, 0.1, 0.2, 0.3, 0.4, 0.5) and compares the electrochemical performance difference with z to the proposed percolation network. X-ray diffraction combined with Rietveld refinements show that rock-salt structure is obtained by the simple sol-gel process, and the lattice parameters are increased with the increasing level of Li-excess. Micromorphology observation reveals that particles are irregular and the size is distributed within 100 nm. In addition, a detailed reaction mechanism is examined by X-ray photoelectron spectroscopy and cyclic voltammetry, which exhibits the evolution of Ni, Ti and O in the initial charge-discharge process and confirms that they all make contributions to capacities. Electrochemical performance test shows that the discharge capacities increase with the amount of Li and Li 1.17 Ni 0.25 Ti 0.58 O 2 delivers the discharge capacities up to 223.9 mAh g−1. At the current density of 400 mA g−1, it still provides a large capacity of 120 mAh g−1. Furthermore, Li 1.17 Ni 0.25 Ti 0.58 O 2 has the highest lithium ion diffusion coefficient among all samples. Graphical abstract Image 1 Highlights • The good crystallized Li 1+z/3 Ni 1/2-z/2 Ti 1/2+z/6 O 2 is prepared by a facile method. • The detailed redox process of Ni, Ti and O during the first cycle. • Stable structure and 0-TM network improve performance. • Li 1.17 Ni 0.25 Ti 0.58 O 2 exhibits high capacities and good rate capability. [ABSTRACT FROM AUTHOR]

The homogeneous nano-CeO 2 coated on the LiNi 1/3 Co 1/3 Mn 1/3 O 2 powder like substrate was prepared via a novel hydrolytic precipitation reaction followed by the thoroughly baking at 450 °C. The chemical composite of nano-CeO 2 coating layer was spectroscopically examined by X-ray diffraction, field-emission scanning electron microscopy and X-ray photoelectron spectrometer. The electrochemical characterization of the resulting materials proclaim that nano-CeO 2 coating can drastically improve lithium storage performances. The optimum coating amount of CeO 2 is as high as 2 wt%, which rendered a discharge capacity of 148.9 mAh g −1 with 91.6% capacity retention ensuing as many as 100 cycles. In particular, the exothermic peak is vastly increased from 256.4 to 338.2 °C. The value is superior to its counterparts, LiNi 1/3 Co 1/3 Mn 1/3 O 2 . It paves a new avenue for developing high safety lithium batteries. [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]

Pristine and yttrium-doped LiNi 0.5- x Y x Mn 1.5 O 4 spinel powders ( x = 0, 0.005, 0.01, 0.02, 0.04) were synthesized by a facile solid-state method. The effect of yttrium doping content on the electrochemical properties of LiNi 0.5- x Y x Mn 1.5 O 4 was investigated by using half-cells paired with lithium metal and full-cells paired with graphite. XRD and FT-IR analysis shows that the cation disordering degree (Mn 3+ content) first increase ( x ≤ 0.02) and then decrease with Y doping content and the Y doping can effectively inhibit the formation of Li x Ni 1- x O impurity phase. Electrochemical results show that in half-cells, the LiNi 0.5-x Y x Mn 1.5 O 4 cathode material with appropriate Y doping ( x = 0.01) exhibits optimal rate capability and cycling stability, due to higher phase purity, enlarged lattice parameter, higher disordering degree, higher structural stability by introducing Y O bond, lower charge transfer resistance and higher lithium ion diffusion coefficient, although the 0.2C discharge capacity is slightly lower than pristine LiNi 0.5 Mn 1.5 O 4 . Atomic Absorption Spectroscopy result shows that appropriate Y doping can effectively decrease the transition metal dissolution to certain extent, despite of higher Mn 3+ content. All above factors lead to the improved cycling performance of Y-doped electrode in half-cells paired with metallic Li at elevated temperature (55 °C) and in full-cells paired with graphite at room temperature. [ABSTRACT FROM AUTHOR]

As a high-capacity hydrogen storage material, MgH 2 also shows specific advantages for LIB anode. In this work, MgH 2 and MgH 2 -C films were prepared by magnetron sputtering and hydrogenation treatment, and their microstructural and electrochemical properties were investigated. Through the conversion reaction of MgH 2 with lithium (MgH 2 + 2Li + → Mg + 2LiH), the reversible lithium storage was achieved in the MgH 2 and MgH 2 -C films. The MgH 2 film delivers the initial discharge capacity of 313.9 μAh cm −2 (∼2956 mAh g −1 ), the discharge and charge capacities related to the conversion process are respectively 150.0 μAh cm −2 (∼1412 mAh g −1 ) and 55.0 μAh cm −2 (∼518 mAh g -1 ), with the inefficiency of 63.3%. The GITT measurement determined the equilibrium potential of this conversion reaction to be 0.55 V vs. Li/Li + , and the voltage hysteresis between discharge and charge is only 10 mV vs. Li/Li + . In comparison with the MgH 2 film, the MgH 2 -C film has smaller crystallite size, lower polarization effect and structural stability, but exhibiting lower capacity and equally poor cyclic performance. The poor cycle life of MgH 2 -C film electrode is due to the large irreversibility of conversion reaction of MgH 2 , instead of structural damage of film electrode during cycling. [ABSTRACT FROM AUTHOR]

Particle morphology structure design combined with surface modification has been applied to improve the electrochemical properties of lithium rich layered oxides. Hollow spherical lithium rich layered Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 oxides with different shell thickness are synthesized by co-precipitation followed by calcination. The morphology and interior structure have been investigated by SEM and cross section, and their electrochemical properties have been evaluated to identify an appropriate shell thickness. Furthermore, a Zr compound coating layer has been applied to modify the interface between corrosive electrolyte and hollow spherical particles with an appropriate shell thickness. The Electrochemical impedance spectroscopy shows hollow spherical structure and Zr compound coating layer both can modificate the electronic and ionic transmission capacities and inhibit their deterioration during charge-discharge process at the same time. The HRTEM tests indicate that hollow spherical structure and Zr compound coating layer can dramatically suppress Mn dissolution in electrolyte and make the crystal structure more stable during the electrode process. Therefore, a surface modification combine with the hollow spherical structure (with an appropriate shell thickness) can effectively enhance these electrochemical properties of lithium ion layered oxides. [ABSTRACT FROM AUTHOR]

FeCO 3 with the morphology of microspheres and rice-like were successfully fabricated by a facile mixed solvothermal method by using urea and ammonium bicarbonate as precipitants, respectively. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical properties of the samples were investigated by battery testing system. The influences of different precipitants on its structure, morphology and the electrochemical properties were also discussed. The results showed that the diameter of FeCO 3 microspheres (FCO-1) was 8–10 μm by using urea as precipitant, while the size of FeCO 3 rice-like (FCO-2) by using ammonium bicarbonate as precipitant was 0.5–1.0 μm. When used as an anode material for lithium ion batteries, FCO-1 and FCO-2 delivered the initial specific discharge capacities of 1563.54 and 1518.09 mAh g −1 at the current density of 100 mA g −1 in the voltage range of 0.01–3 V and remained its reversible value of 854.65 and 1019.47 mAh g −1 over 100 cycles, respectively. The FCO-2 still possessed a considerable capacity of 890.23 mAh g −1 at a high current density of 500 mA g −1 . Therefore, FCO-2 synthesized through using ammonium bicarbonate as precipitant could be a potential anode candidate for lithium ion batteries. [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]

Micron-sized Co 3 O 4 hollow powders consisting of size controlled hollow nanospheres are prepared by applying Ostwald ripening and Kirkendall effect to the spray pyrolysis process. The Co-C composite powders uniformly dispersed with different sizes of metallic Co nanocrystals are formed by reduction of the cobalt oxide-carbon composite powders prepared using spray pyrolysis. Subsequent oxidation of the Co-C composite powders with filled structures forms the micron-sized Co 3 O 4 hollow powders consisting of size controlled hollow nanospheres. The mean sizes of the Co 3 O 4 hollow nanospheres oxidized from Co-C composite powders formed at reduction temperatures of 400, 600, and 800 °C are 37, 55, and 73 nm, respectively. The discharge capacities of the Co 3 O 4 powders formed from the Co-C composite powders reduced at temperatures of 400, 600, and 800 °C for the 300 th cycle are 644, 702, and 660 mA h g −1 , respectively, and their capacity retentions calculated from the second cycle are 81, 86, and 84%, respectively. The porous-structured Co 3 O 4 powders formed from the Co-C composite powders reduced at 800 °C show slightly better rate performance than those of the other two samples. [ABSTRACT FROM AUTHOR]

MoO 2 has gained renewed attention as a safe oxide anode host material for lithium ion insertion because of its high gravimetric/volumetric capacity and highly stable cycling behavior. However, these recent results are completely contrary to previous reports. To confirm that MoO 2 is an appropriate anode material as well as further understand lithium ion reactions when inserted into MoO 2 , we combine electrochemical characterization of MoO 2 electrodes and ex situ X-ray diffraction analysis with first principle calculations. Theoretical capacity of the MoO 2 electrode (∼209 mAh g −1 ) and stable capacity retention up to 100 cycles are simultaneously attained using a proper particle size and type of binder. Ex situ XRD analysis with first principle calculations of the phase transformation of MoO 2 electrodes shows that MoO 2 undergoes reversible structural changes upon lithiation and subsequent delithiation, clearly demonstrating that nanostructured MoO 2 can be used as an anode material for highly reliable lithium ion batteries. [ABSTRACT FROM AUTHOR]

Li 2 FeSiO 4 was synthesized through Sol–Gel method and the effect of calcination temperature, time and chelating agent concentration were investigated. Appropriate calcination temperature above 550 °C was determined by TG/DTA analysis. Afterward, the dried gel powder was calcined at each temperature of 650 °C, 700 °C and 750 °C for 1, 2 and 3 h. XRD studies illustrated the most appropriate calcination temperature of 700 °C for 1 h. To compare the effect of chelating agent concentration, citric acid with molar ratio of 1/3, 2/3 and 1 were used which 1/3 was determined as the best concentration. FE-SEM observation showed that mean grain is size lower than 100 nm. By using this material, a three electrodes test cell was assembled and its electrochemical properties were investigated. The results showed high charge capacity which could be achieved at current density of 0.05C. [ABSTRACT FROM AUTHOR]

Introducing the Mg ion into host lattice is applied to improving the electrochemical performance of LiNi 0.6 Co 0.2 Mn 0.2 O 2 . The effect of Mg substitution for Co on the structure, morphology, electrochemical properties and Li + diffusion coefficients are investigated in details. Rietveld refinement results reveal that Mg is incorporated into the bulk lattice, which results in reduced cation mixing and expand c -lattice parameter. All Mg-doped sample exhibit better cycle and rate performances, although the Mg substitution for Co led to decreasing a part of capacity. The Li diffusion coefficients obtained by galvanostatic intermittent titration technique (GITT) are increased with increases of Mg content. [ABSTRACT FROM AUTHOR]

LiNi 1/3 Co 1/3 Mn 1/3 O 2 is successfully coated with MnO 2 by a chemical deposition method. The X-ray diffraction (XRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) results demonstrate that MnO 2 forms a thin layer on the surface of LiNi 1/3 Co 1/3 Mn 1/3 O 2 without destroying the crystal structure of the core material. Compared with pristine LiNi 1/3 Co 1/3 Mn 1/3 O 2 , the MnO 2 -coated sample shows enhanced electrochemical performance especially the rate capability. Even at a current density of 750 mA g −1 , the discharge capacity of MnO 2 -coated LiNi 1/3 Co 1/3 Mn 1/3 O 2 is 155.15 mAh g −1 , while that of the pristine electrode is only 132.84 mAh g −1 in the range of 2.5–4.5 V. The cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) curves show that the MnO 2 coating layer reacts with Li + during cycling, which is responsible for the higher discharge capacity of MnO 2 -coated LiNi 1/3 Co 1/3 Mn 1/3 O 2 . Electrochemical impedance spectroscopy (EIS) results confirmed that the MnO 2 coating layer plays an important role in reducing the charge transfer resistance on the electrolyte–electrode interfaces. [ABSTRACT FROM AUTHOR]

Layered-spinel composite cathode material Li 1.1 Ni 0.25 Mn 0.75 O 2.3 has been synthesized and cooled by different methods (naturally cooled within the furnace and cooled in liquid nitrogen). The effect of cooling methods on physical and electrochemical properties are discussed using the characterizations of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), charge/discharge, cyclic and rate tests. The layered-spinel composite structure has been detected in Li 1.1 Ni 0.25 Mn 0.75 O 2.3 electrodes from the XRD patterns and TEM images. XPS results show that the content of Mn 3+ in the Li 1.1 Ni 0.25 Mn 0.75 O 2.3 cooled in liquid nitrogen is more than that of Li 1.1 Ni 0.25 Mn 0.75 O 2.3 cooled with furnace. The electrochemical performance results show that the Li 1.1 Ni 0.25 Mn 0.75 O 2.3 cooled in liquid nitrogen has higher initial discharge capacity, coulomb efficiency, better cyclic and rate performance compared with Li 1.1 Ni 0.25 Mn 0.75 O 2.3 cooled with furnace. EIS results show that the charge transfer resistance ( R ct ) of Li 1.1 Ni 0.25 Mn 0.75 O 2.3 cooled in liquid nitrogen is lower than that of Li 1.1 Ni 0.25 Mn 0.75 O 2.3 cooled with furnace. The improved cyclic and rate performances of Li 1.1 Ni 0.25 Mn 0.75 O 2.3 cooled in liquid nitrogen cathode are attributed to the lower R ct and more content of Mn 3+ . [ABSTRACT FROM AUTHOR]

LiFePO 4 /graphene active material (LFP/G) was successfully synthesized via a simple, low raw material cost and environment friendly hydrothermal method at 170 °C. LFP/G composite was prepared in a template-free method using graphene nano-sheets as a conductive additive (3.0 wt.%) without any carbon coating. Results indicated the presence of LFP crystallites of the olivine phase, which are randomly anchored on the surface of graphene. Electrochemical characteristics of the LFP/G modified electrode show well-defined peaks, smaller peak potential separation and higher cycling stability compared to those of the pristine LFP obtained in the absence of graphene. LFP/G delivered an initial discharge capacity of 157 mA h g −1 at 0.2 C and 114 mA h g −1 at 5 C and the values were compared to those of LFP (the capacities reach up to 120 mA h g −1 at 0.1 C and 50 mA h g −1 at 5 C). The electrochemical enhancement of LFP/G could be mainly ascribed to synergetic effects of bridging graphene nanosheets and creating an interconnected conducting network of cross-linking between neighboring crystallites. Such network would enhance the stability of the cathode composite and buffer spaces to accommodate the volume pulsation during charge/discharge cycling. [ABSTRACT FROM AUTHOR]

Spherical LiMn 2 O 4 nanoparticles were successfully prepared via solution combustion synthesis by controlling calcinating temperature. XRD results indicate that high purity LiMn 2 O 4 can be fabricated by calcinating the precursor above 600 °C. SEM results reflect that LiMn 2 O 4 calcinated lower than 600 °C are composed of nanoparticles about 100 nm. Therefore, LiMn 2 O 4 calcinated at 600 °C possess high purity and nanoparticles, which ensure the most excellent electrochemical performance among the precursor as well as LiMn 2 O 4 calcinated at 500 °C, 600 °C and 700 °C. LiMn 2 O 4 calcinated at 600 °C even can deliver a capacity of 103.8 mA h g −1 at 10 C, which is the 83.6% of the capacity at 0.2 C. It also displays excellent capacity retention ratio of 95.1% for 100 cycles at constant current rate of 1 C. [ABSTRACT FROM AUTHOR]

Highlights: [•] LNMO and LANMO hollow microspheres are synthesized by template method. [•] The as-synthesized hollow microspheres have particle-size of 2μm. [•] The hollow structure is responsible for improved electrochemical performance. [ABSTRACT FROM AUTHOR]

Highlights: [•] Carbon-coated V2O5 was synthesized in a scalable and easy method using a carbon form as a template. [•] Electrochemical performance of the carbon-coated V2O5 was significantly improved compared to nano-sized V2O5. [•] The carbon-coated V2O5 calcined at 400°C showed enhanced capacity retention and rate capabilities. [ABSTRACT FROM AUTHOR]

Highlights: [•] To improve the electrochemistry of LiMn2O4 by partial substitution of Li by Na. [•] Na-substitution can improve the cycling stability. [•] A new, low-cost method to improve its electrode properties due to low-cost of Na resource. [ABSTRACT FROM AUTHOR]

Abstract: Li3V2(PO4)3/C cathode material was synthesized by using a freeze-drying method followed by carbon-thermal reduction. This as-prepared material has a uniform particle size distribution and a well carbon coating on the surface of Li3V2(PO4)3 particles. The Li3V2(PO4)3/C exhibits good electrochemical performance and cycling stability. Between 3.0 and 4.3V, the composite delivered a reversible capacity of 125.2mAhg−1 at a charge–discharge rate of 1.48C (1C=133mAg−1) and without obviously capacity fading after 100 cycles. Even at 14.8C and 29.6C rates, it can still deliver discharge capacities of 105.6mAhg−1 and 93.3mAhg−1, and the discharge capacities of 84.5 and 60.5mAhg−1 are sustained after 500 cycles, respectively. [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: The hybrid LiNi0.5Mn1.5O4/C cathode material is prepared with a facile method of pre-mixing and post-calcination treatment for enhancing the rate performance. The physical and electrochemical properties are discussed through X-ray diffraction (XRD), transmission electron microscopy (TEM), charge–discharge measurements in test cells and electrochemical impedance spectroscopy (EIS). The results show that the LiNi0.5Mn1.5O4 particle can be partially surrounded and interconnected with each other by carbon black particles, therefore the electronic conductivity can be remarkably improved by over 5 times without degrading the spinel structure. The LiNi0.5Mn1.5O4/C composite exhibits enhanced rate capability together with cycling performance compared to LiNi0.5Mn1.5O4. EIS confirms that the significantly improved electrochemical property is due to the suppression of surface resistance and the enhanced electronic conductivity. [Copyright &y& Elsevier]

Abstract: A porous Li4Ti5O12 anode material was successfully synthesized from mixture of LiCl and TiCl4 with 70wt% oxalic acid by a modified one-step solid state method. The anode material Li4Ti5O12 exhibited a cubic spinel structure and only one voltage plateau occurred around 1.5V. The initial capacity of porous Li4Ti5O12 was 167 and 133mAhg−1 at 0.5 and 1C charge/discharge rate, respectively, and the capacity retention maintained above 98% after 200 cycles. The porous Li4Ti5O12 structure showed promising rate performance with a capacity of 70mAhg−1 at charge/discharge 10C rate after 200 cycles. It was demonstrated that the porous structure could withstand 50C charge/discharge rate and exhibited excellent cycling stability. [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: Three precipitators, i.e. Na2CO3, (NH4)2CO3 and NH4HCO3, are employed to prepare Li[Ni1/3Co1/3Mn1/3]O2 via the carbonate coprecipitation method. The effects of precipitator on the morphological, structural and electrochemical characteristics of the prepared samples are studied. The sample prepared by using Na2CO3 as precipitator has irregular particle shape and nonuniform particle size, while the sample prepared by using (NH4)2CO3 as precipitator has spherical particle shape and uniform particle size. Among all the samples, the one prepared with (NH4)2CO3 exhibits the best hexagonal layered structure, which results in its highest discharge capacity and best cycling performance. Therefore, precipitator plays an important role in the coprecipitation reaction and makes a great impact on the characteristics of Li[Ni1/3Co1/3Mn1/3]O2. [ABSTRACT FROM AUTHOR]

Abstract: The surface of LiFePO4/C particles was coated with SiO2 via a sol–gel method, and the electrochemical performance of SiO2-coated LiFePO4 cathode materials at room temperature and 55°C was investigated. Compared with pristine LiFePO4, the structure of LiFePO4 with SiO2 coating had no change, the existence of SiO2 coating effectively enhanced the cycling capacity, reduced capacity fading at high temperature and alleviated the cell impedance. The SiO2 coating played a regulatory role for Li-ion inserting the lattice, by increasing the order of lithium ion intercalating the outer lattice of the particle. As a consequence, capacity retention improves significantly. [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: 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]

Silicon (Si) with high energy density is identified as the most promising candidate for commercial lithium-ion batteries anodes. Unfortunately, the volume expansion severely damages the battery cycle life during cycling, resulting in fast capacity fading during the battery operation. Herein, a facile design was proposed for the preparation of novel tailored mesoporous Si cages (TMSC) to mitigate this issue. The TMSC material, with mesoporous anamorphic spherical shells and nano-sized Si cores, consists of numerous interconnected channels and forms a half open three-dimensional network. When evaluated as electrode material for lithium-ion batteries, it exhibits the reversible capacity of 931.1 mAh/g after 200 cycles at 1 A/g, which is more stable than that of Si pomegranates with intact shells. Moreover, it displays a high rechargeable capacity of 552.3 mA h/g over 500 cycles at 4 A/g and the capacity decay ratio is only 0.11% for each cycle. Image 1 • A novel kind of tailored mesoporous Si cages (TMSC) material was facile prepared. • The TMSC material demonstrates tailored mesopores on the shell and cross-linked Si nanoparticles in the core. • The TMSC electrode exhibits a high rate capability of 552.3 mA h/g over 500 cycles at 4 A/g. [ABSTRACT FROM AUTHOR]

Abstract: Fe3O4 micro-spheres with nanoparticles close-packed architectures were synthesized via a simple chemical method using (NH4)2Fe(SO4)2·6H2O, hexamethylenetetramine, and NaF as reaction materials. This chemical synthesis took place in a vitreous jar under low temperature (90°C) and atmospheric pressure. The morphology and structure of the as-synthesized products were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and Raman spectrum. Electrochemical properties of the as-synthesized Fe3O4 micro-spheres as anode electrode of lithium ion batteries were studied by conventional charge/discharge tests, which exhibit steady charge/discharge platforms at different current densities. The as-prepared Fe3O4 electrode shows high initial discharge capacity of 1166 and 1082mAhg−1 at current density of 0.05 and 0.1mAcm−2, respectively. [Copyright &y& Elsevier]