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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: A modular electronic battery management system (BMS) is described along with important features for protecting and optimizing the performance of large lithium ion (LiIon) battery packs. Of particular interest is the use of a much improved cell equalization system that can increase or decrease individual cell voltages. Experimental results are included for a pack of six series connected 60Ah (amp-hour) LiIon cells. [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: Attempts to dope Zn2+, Cu2+ or Ni2+ are made for Li2FeSiO4. The effects of dopant on the physical and electrochemical characteristics of Li2FeSiO4 were investigated. Zn2+ successfully entered into the lattice of Li2FeSiO4 and induced the change of lattice parameters. Compared with the undoped Li2FeSiO4, Li2Fe0.97Zn0.03SiO4 has higher discharge capacity, better electrochemical reversibility and lower electrode polarization. The improved electrochemical performance of Li2Fe0.97Zn0.03SiO4 can be attributed to the improved structural stability and the enhanced lithium ion diffusivity brought about by Zn2+ doping. However, Ni2+ and Cu2+ cannot be doped into the lattice of Li2FeSiO4. Cu and NiO are formed as impurities in the Cu- and Ni-containing samples, respectively. Compared with the undoped Li2FeSiO4, the Cu- and Ni-containing samples have lower capacities and higher electrochemical polarization. [ABSTRACT FROM AUTHOR]

Abstract: 9LiFePO4·Li3V2(PO4)3/C is synthesized via a carbon thermal reaction using petroleum coke as both reduction agent and carbon source. The as-prepared material is not a simple mixture of LiFePO4 (LFP) and Li3V2(PO4)3 (LVP), but a composite possessing two phases: one is V-doped LFP and the other is Fe-doped LVP. The typical structure enhances the electrical conductivity of the composite and improves the electrochemical performances. The first discharge capacity of 9LFP·LVP/C in 18650 type cells is 168mAhg−1 at 1C (1C9LFP·LVP/C =166mAg−1), and exhibits high reversible discharge capacity of 125mAhg−1 at 10C even after 150 cycles. At the temperature of −20°C, the reversible capacity of 9LFP·LVP/C can maintain 75% of that at room temperature. [Copyright &y& Elsevier]

Abstract: Nanosized Sn–Co prepared by ultrasonic-assisted chemical reduction is milled with artificial graphite (AG) to form Sn–Co–AG composite. The as-prepared materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectrometry and Brunauer–Emmett–Telle (BET) surface area measurement. XRD patterns show that Sn–Co particles are poorly crystallized and artificial graphite has a typical hexagonal graphite structure phase. The diffraction peaks of Sn–Co particles remain the same but some of AG obviously change after milling Sn–Co with AG. BET areas of AG, Sn–Co and Sn–Co–AG are 1.569, 13.187 and 6.754m2 g−1, respectively. SEM images display the as-prepared Sn–Co particles have a size distribution ranging from 20 to 70nm in diameter. After milling Sn–Co with AG, Sn–Co particles keep similar morphology but there is a perceptible change in AG. Electrochemical tests show that Sn–Co–AG composite possesses much improved electrochemical performance than the state-of-the-art graphite. This composite has great potential as an alternative material for improving the energy density of a lithium ion secondary battery. [Copyright &y& Elsevier]

This paper reported on a new gel polymer electrolyte (GPE) based on polyethylene (PE) non-woven fabric supported poly(acrylonitrile-vinyl acetate) (P(AN-VAc)/PE) membrane for lithium ion battery use. The preparation and performances of the P(AN-VAc)/PE membrane and its GPE based on 1 M LiPF in dimethyl carbonate/diethylene carbonate/ethylene carbonate (1:1:1 in volume) were investigated with a comparison of the unsupported P(AN-VAc) membrane. It is found that the P(AN-VAc)/PE membrane shows better mechanical strength and pore structure for electrolyte uptake than the P(AN-VAc) membrane, and subsequently the GPE based on P(AN-VAc)/PE exhibits higher ionic conductivity and electrochemical stability on cathode than the GPE based on P(AN-VAc). With the support of the non-woven fabric, the ionic conductivity of the GPE at room temperature increases from 1.4 to 3.8 mS cm, the oxidation decomposition potential of the GPE on a stainless steel is improved from 5.0 to 5.6 V (vs. Li/Li). The mesocarbon microbeads (MCMB)/LiMnO battery using P(AN-VAc)/PE as separator retains 94% of its initial discharge capacity after 100 cycles at C/2 rate, showing that the P(AN-VAc)/PE membrane is a possible alternative to the expensive separator for current liquid lithium ion battery. [ABSTRACT FROM AUTHOR]

Abstract: To enhance the safety of lithium ion battery, cresyl diphenyl phosphate (CDP) is explored as an additive in 1.0M LiPF6/ethylene carbonate (EC)+diethyl carbonate (DEC) (1:1wt.). The electrochemical performances of LiCoO2/CDP-electrolyte/C cells are tested. At the thermal aspect, the thermal stability of the electrolyte with CDP is detected firstly by using a C80 micro-calorimeter, and then the charged LiCoO2/CDP-electrolyte/C cells are disassembled and wrapped to detect the thermal behaviors. The results indicate that CDP-containing electrolyte enhances the thermal stabilities of electrolyte and lithium ion battery, and the electrochemical performances of LiCoO2/CDP-electrolyte/C cell become slightly worse by using CDP in the electrolyte. Furthermore, the cell with 10% (wt.) CDP-containing electrolyte shows better cycle efficiency than that of other CDP-containing electrolyte, such as containing 5% (wt.) CDP and 15% (wt.) CDP. This maybe because that the mass ratio between CDP and electrolyte is close to the reaction stoichiometric ratio in the 10% (wt.) CDP-containing electrolyte, where stable solid electrolyte interphase (SEI) is formed. Therefore, 10% CDP-containing electrolyte improves the safety of lithium ion battery and keeps its electrochemical performance. [Copyright &y& Elsevier]

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: SnO2/graphene nanocomposite was prepared via an in situ chemical synthesis method. The nanocomposite was characterized by X-ray diffraction, filed emission scanning electron microscope and transmission electron microscope, which revealed that tiny SnO2 nanoparticles could be homogeneously distributed on the graphene matrix. The electrochemical performance of the SnO2/graphene nanocomposite as anode material was measured by galvanostatic charge/discharge cycling. The SnO2/graphene nanocomposite showed a reversible capacity of 665mAh/g after 50cycles and an excellent cycling performance for lithium ion battery, which was ascribed to the three-dimensional architecture of SnO2/graphene nanocomposite. These results suggest that SnO2/graphene nanocomposite would be a promising anode material for lithium ion battery. [ABSTRACT FROM AUTHOR]

The electronic structure and electrochemical parameters of ternary NiSn0.5Ti0.5 phase are investigated by plane-wave pseudopotential method of the first-principle. The interstitial sites are firstly filled with lithium atoms, and then the substitution for Ni sites occurs. The results show that the Fermi level of lithium-intercalated phase goes up with the increasing lithium concentration. These interactions of M-M covalent bonds (M=Ni, Sn, Ti) become weak, while Li-M bonds are found to increase. NiSn0.5Ti0.5 phase is characterized with high theoretical capacity and low voltage of lithium-intercalation. The obvious volume effect from 77.15% to 189.94% would lead to the failure of the electrode material, and therefore the NiSn0.5Ti0.5 compound should be limited as low as possible in multi-element Sn-based alloy. [ABSTRACT FROM AUTHOR]

Abstract: Li3V2(PO4)3, Li3V2(PO4)3/C and Li3V2(PO4)3/(Ag+C) composites as cathodes for Li ion batteries are synthesized by carbon-thermal reduction (CTR) method and chemical plating reactions. The microstructure and morphology of the compounds are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Li3V2(PO4)3/(Ag+C) particles are 0.5–1μm in diameters. As compared to Li3V2(PO4)3, Li3V2(PO4)3/C, the Li3V2(PO4)3/(Ag+C) composite cathode exhibits high discharge capacity, good cycle performance (140.5mAhg−1 at 50th cycle at 1C, 97.3% of initial discharge capacity) and rate behavior (120.5mAhg−1 for initial discharge at 5C) for the fully delithiated (3.0–4.8V) state. Electrochemical impedance spectroscopy (EIS) measurements show that the carbon and silver co-modification decreases the charge transfer resistance of Li3V2(PO4)3/(Ag+C) cathode, and improves the conductivity and boosts the electrochemical performance of the electrode. [Copyright &y& Elsevier]

Monodisperse Li4Ti5O12 hollow spheres were prepared by using carbon spheres as templates. Scanning electron microscopy images show hollow spheres that have an average outer diameter of 1.0 μm and an average wall thickness of 60 nm. Compared with Li4Ti5O12 solids, the hollow spherical Li4Ti5O12 exhibit an excellent rate capability and capacity retention and can be charged/discharged at 10 C (1.7 A g−1) with a specific capacity of 100 mA h g−1, and after 200 charge and discharge cycles at 2 C, their specific capacity remain very stable at 150 mA h g−1. It is believed that the hollow structure has a relatively large contact surface between Li4Ti5O12 and liquid electrolyte, resulting in a better electrochemical performance at high charge/discharge rate. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the mechanism of enhanced performance of ZrO2-coated LiCoO2 especially at high potential range is systematically investigated. Firstly, when overcharging to 4.5V (higher than 4.2V, the normal cutoff charging potential), phase transformation from H1 to H2 takes place with less volume expansion for ZrO2-coated LiCoO2 (1.2% and 2.2% for as-received one). EIS analysis indicates the growth of interfacial impedance during charging/discharging can be effectively suppressed with ZrO2 coating on the LiCoO2 surface. It is demonstrated as well that cation mixing of the cycled LiCoO2 caused by re-intercalation of dissolved Co2+ is inhibited with the ZrO2 coating on the LiCoO2. Therefore the ZrO2-coated LiCoO2 shows great enhancement in the electrochemical properties with 85% capacity retention after 30 cycles from 3 to 4.5V at a rate of 0.5C. Nevertheless, under the same evaluation process, the as-received LiCoO2 possesses only 21% capacity retention, which is resulted from the formation of polymeric layers by the electrolyte decomposition on its surface, the higher volumetric changes during charging/discharging and possible cation mixing by re-intercalation of the dissolved Co2+. [Copyright &y& Elsevier]

The olivine-typed cathode materials of LiFePO4were prepared via solid-state reaction under argon atmosphere and co-doped by manganese and fluorine to improve their electrochemical performances. The crystal structure, morphology, and electrochemical properties of the prepared samples were investigated using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectrum, X-ray photoelectron spectroscopy, cyclic voltammetry, and charge–discharge cycle measurements. The result showed that the electrochemical performance of LiFePO4 had been improved dramatically by Mn–F co-doping. The initial discharge capacity of LiFe0.99Mn0.01 (PO4)2.99/3F0.01/C samples reached 140.2 mAh/g at 1C rate and only had a small amount of fading in 50 cycles. [ABSTRACT FROM AUTHOR]

Abstract: LiFePO4–Li3V2(PO4)3 composite cathode material is synthesized by aqueous precipitation of FeVO4·xH2O from Fe(NO3)3 and NH4VO3, following chemical reduction and lithiation with oxalic acid as the reducer and carbon source. Samples are characterized by XRD, SEM and TEM. XRD pattern of the compound synthesized at 700°C indicates olivine-type LiFePO4 and monoclinic Li3V2(PO4)3 are co-existed. TEM image exhibits that LiFePO4–Li3V2(PO4)3 particles are encapsulated with a carbon shell 5–10nm in thickness. The LiFePO4–Li3V2(PO4)3 compound cathode shows good electrochemical performance, and its discharge capacity is about 139.1 at 0.1C, 135.5 at 1C and 116mAhg−1 at 3C after 30 cycles. [Copyright &y& Elsevier]

Abstract: A novel CuO-nanotubes/SnO2 composite was prepared by a facile solution method and its electrochemical properties were investigated as the anode material for Li-ion battery. The as-prepared composite consisted of monoclinic-phase CuO-nanotubes and cassiterite structure SnO2 nanoparticles, in which SnO2 nanoparticles were dramatically decorated on the CuO-nanotubes. The composite showed higher reversible capacity, better durability and high rate performance than the pure SnO2. The better electrochemical performance could be attributed to the introducing of the CuO-nanotubes. It was found that the CuO-nanotubes were reduced to metallic Cu in the first discharge cycle, which can retain tube structure of the CuO-nanotubes as a tube buffer to alleviate the volume expansion of SnO2 during cycling and act as a good conductor to improve the electrical conductivity of the electrodes. [Copyright &y& Elsevier]

Abstract: Well-crystallized LiFePO4 nanoparticles have been directly synthesized in a short time via hydrothermal process in the presence of organic acid, e.g. citric acid or ascorbic acid. These acid-mediated LiFePO4 products exhibit a phase-pure and nanocrystal nature with size about 50–100nm. Two critical roles that the organic acid mediator plays in hydrothermal process are recognized and a rational mechanism is explored. After a post carbon-coating treatment at 600°C for 1h, these mediated LiFePO4 materials show a high electrochemical activity in terms of reversible capacity, cycling stability and rate capability. Particularly, LiFePO4 mediated by ascorbic acid can deliver a capacity of 162mAhg−1 at 0.1C, 154mAhg−1 at 1C, and 122mAhg−1 at 5C. The crystalline structure, particle morphology, and surface microstructure were characterized by high-energy synchrotron X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and Raman spectroscopy, respectively. And the electrochemical properties were thoroughly investigated by galvanostatic test and electrochemical impedance spectroscopy (EIS). [Copyright &y& Elsevier]

Abstract: Amorphous carbon films were deposited successfully on Cu foils by DC magnetron sputtering technique. Electrochemical performance of the film as lithium battery anode was evaluated across Li metal at 0.2C rate in a non-aqueous electrolyte. The discharge curves showed unusually low irreversible capacity in the first cycle with a reversible capacity of ∼810mAhg−1, which is at least 2 times higher than that of graphitic carbon. For the first time we report here an amorphous carbon showing such a high reversibility in the first cycle, which is very much limited to the graphitic carbon. The deposited films were extensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and step profilometer for the structural and surface properties. The hydrogen content of the synthesized films was studied using residual gas analysis (RGA). The low hydrogen content and the low specific surface area of the synthesized amorphous carbon film are considered responsible for such a high first cycle columbic efficiency. The growth mechanism and the reasons for enhanced electrochemical performance of the carbon films are discussed. [Copyright &y& Elsevier]

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]

Carbon nano-coated LiNi0.8Co0.15Al0.05O2/C (LNCAO/C) cathode-active materials were prepared by a sol–gel method and investigated as the cathode material for lithium ion batteries. Electrochemical properties including the galvanostatic charge–discharge ability and cyclic voltammogram behavior were measured. Cyclic voltammetry (2.7–4.8 V) showed that the carbon nano-coating improved the "formation" of the LNCAO electrode, which was related to the increased electronic conductivity between the primary particles. The carbon nano-coated LNCAO/C exhibited good electrochemical performance at high C-rate. Also, the thermal stability at a highly oxidized state of the carbon nano-coated LNCAO was remarkably enhanced. The carbon nano-coating layer can serve as a physical and/or (electro-)chemical protection shell for the underlying LNCAO, which is attributed to an increase of the grain connectivity (physical part) and also to the protection of metal oxide from chemical reactions (chemical part). [ABSTRACT FROM AUTHOR]

Abstract: Ultra-thin Cr2O3 films (12.0, 17.3 and 29.6nm thick) were produced on Cr metal by thermal oxidation, and their electrochemical properties in 1M LiClO4 in propylene carbonate (PC) were investigated by cyclic voltammetry and chronopotentiometry. The reductive electrolyte decomposition and the conversion/deconversion process were observed and analyzed by X-ray photoelectron spectroscopy (XPS), polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The initial irreversible capacity due to the reduction of electrolyte and the incomplete deconversion process during the first cycle is 70% of the first discharge capacity. A stable charge/discharge capacity of 460mAhg−1 was obtained in the 3rd to 10th cycles. XPS and PM-IRRAS evidenced the growth of a solid electrolyte interphase (SEI) layer that is constituted of Li2CO3 formed by reductive decomposition of the electrolyte. The SEI layer thickness and/or density is modified by the conversion/deconversion reaction. ToF-SIMS evidenced the volume expansion/shrink resulting from the conversion/deconversion reaction. ToF-SIMS also revealed an incomplete conversion process limited by mass transport, which partitions the oxide into a converted outer part assigned to Li2O containing Cr traces and an unconverted inner part ascribed to Cr2O3 or lower Cr oxide containing Li. It was found that the deconversion re-homogenizes the oxide film in a single layer but with lithium trapped in it. The present study provides a detailed understanding of the interfacial reaction on the oxide anode undergoing a conversion/deconversion reaction. [Copyright &y& Elsevier]

Abstract: A series of monoclinic Li3V2(PO4)3 cathode materials were prepared by H2 reduction (LVP-H2) and carbothermal reduction (LVP-CTR) methods. LVP-H2 showed a primary particle size of about 1 μm, which was much larger than the LVP-CTR samples. A uniform surface carbon layer was observed for the LVP-CTR samples by transmission electron microscope. This carbon layer not only limited the particle growth of the materials but also enhanced the material''s electronic conductivity by five orders of magnitude. The LVP-CTR samples exhibited much better electrochemical performance than LVP-H2. The good electrochemical performance of LVP-CTR was attributed to its nano particle size, high electronic conductivity, as well as the surface carbon layer which limited the vanadium dissolution in electrolyte. [Copyright &y& Elsevier]

Abstract: A series of spinel oxy-fluorides with the formula LiMn1.8Li0.1Ni0.1O4− η F η have been synthesized by both the conventional high-temperature (800 °C) firing method with LiF and a low temperature (450 °C) firing process with NH4HF2. Interestingly, the samples obtained by the high temperature (800 °C) procedure show no fluorine in the sample as revealed by the chemical analysis data, but an increase in lattice parameter and capacity values was observed due to a decrease in lithium content caused by the volatilization of LiF during the high temperature (800 °C) firing process. In contrast, the low-temperature fluorine doping approach was successful in incorporating fluorine into the spinel lattice, and the sample LiMn1.8Li0.1Ni0.1O3.85F0.15 exhibits a significant increase in discharge capacity compared to the oxide analog. [Copyright &y& Elsevier]

Abstract: Binary conductive additives (BCA), formed by sonication of mesoporous carbon (MC) and acetylene black (AB), were used as conductive additives to improve the electrochemical performance of a LiCoO2 composite cathode. The electrochemical performance of the LiCoO2 composite cathode dispersed with BCA was investigated. The results showed that the electrochemical performance (including the discharge capacity, the discharge voltage and the total internal resistance) of a BCA loaded LiCoO2 composite cathode was better than that of a cathode loaded with AB. The possible mechanism is that the MC in BCA can adsorb and retain electrolyte solution, which allows an intimate contact between the lithium ions and the cathode active material LiCoO2 due to its large mesopore specific surface area. A simplified model was also proposed. [Copyright &y& Elsevier]

Abstract: Layered LiNi0.5Mn0.5− x Al x O2 (x =0, 0.02, 0.05, 0.08, and 0.1) series cathode materials for lithium-ion batteries were synthesized by a combination technique of co-precipitation and solid-state reaction, and the structural, morphological, and electrochemical properties were examined by XRD, FT-IR, XPS, SEM, CV, EIS, and charge–discharge tests. It is proven that the aliovalent substitution of Al for Mn promoted the formation of LiNi0.5Mn0.5− x Al x O2 structures and induced an increase in the average oxidation number of Ni, thereby leading to the shrinkage of the lattice volume. Among the LiNi0.5Mn0.5− x Al x O2 materials, the material with x =0.05 shows the best cyclability and rate ability, with discharge capacities of 219, 169, 155, and 129 mAh g−1 at 10, 100, 200, and 400 mA g−1 current density respectively. Cycled under 40 mA g−1 in 2.8–4.6 V, LiNi0. 5Mn0.45Al0.05O2 shows the highest discharge capacity of about 199 mAh g−1 for the first cycle, and 179 mAh g−1 after 40 cycles, with a capacity retention of 90%. EIS analyses of the electrode materials at pristine state and state after first charge to 4.6 V indicate that the observed higher current rate capability of LiNi0. 5Mn0.45Al0.05O2 can be understood due to the better charge transfer kinetics. [Copyright &y& Elsevier]

Abstract: Lithium transition metal oxide powders such as LiMn2O4, LiNi0.5Mn1.5O4, LiCo1/3Ni1/3Mn1/3O2 and LiFePO4 were prepared by spray pyrolysis. The particle characteristics of them were determined by SEM, XRD, BET and AAS. Lithium transition metal oxide powders had spherical morphology of 1–2μm with narrow size distribution and homogeneous chemical composition. The electrochemical properties of cathode were also estimated by rechargeable capacity, cycle performance, thermal stability and high rate charging. The cathodes obtained by spray pyrolysis exhibited that the discharge capacity of LiMn2O4, LiNi0.5Mn1.5O4, LiCo1/3Ni1/3Mn1/3O2 and LiFePO4 was 120, 130, 170 and 150mAh/g, respectively and stable up to 500 cycles at a rate of 1C. Mass production of lithium transition metal oxide powders was carried out by using internal combustion type of spray pyrolysis. The electrochemical properties of cathode obtained by internal combustion type spray pyrolysis were comparable with those obtained by spray pyrolysis. [Copyright &y& Elsevier]

Abstract: Silicon and silicon containing compounds are attractive anode materials for lithium batteries because of their low electrochemical potential vs. lithium and high theoretical capacities. In this work the relationship between the electrochemical performance of silicon powders and their particle sizes was studied. It is found that the material with nano particle sizes gives the best performance. New silicon/carbon composite anode materials were synthesized and their structures and electrochemical performance were investigated. The results of these studies are reported in this paper. [Copyright &y& Elsevier]

Abstract: The LiNi1/3Co1/3Mn1/3O2/Ag composite used for cathode material of lithium ion battery was prepared by thermal decomposition of AgNO3 added to commercial LiNi1/3Co1/3Mn1/3O2 powders to improve the electrochemical performance of LiNi1/3Mn1/3Co1/3O2. Structure and morphology analysis showed that Ag particles were dispersed on the surface of LiNi1/3Co1/3Mn1/3O2 instead of entering the crystal structure. The results of charge–discharge tests showed that Ag additive could improve the cycle performance and high-rate discharge capability of LiNi1/3Mn1/3Co1/3O2. Extended analysis indicated that Ag was unstable in the commercial electrolyte at high potential. The improved electrochemical performance caused by Ag additive was associated not only with the enhancement of electrical conductivity of the material and the lower polarization of the cell, but also with the increased “c” parameter of LiNi1/3Mn1/3Co1/3O2 after repeated charge/discharge cycles and the compact and protective SEI layer formed on the surface of LiNi1/3Mn1/3Co1/3O2. [Copyright &y& Elsevier]

Li1.3Al0.3Ti1.7(PO4)3-coated LiMn2O4 was prepared by wet chemical route. The phase, surface morphology, and electrochemical properties of the prepared powders were characterized by X-ray diffraction, scanning electron micrograph, and galvanostatic charge-discharge experiments. Li1.3Al0.3Ti1.7(PO4)3-coated LiMn2O4 has similar X-ray diffraction patterns as LiMn2O4. The corner and border of Li1.3Al0.3Ti1.7(PO4)3-coated LiMn2O4 particles are not as clear as the uncoated one. The two powders show similar values of lithium-ion diffusion coefficient. When cycled at room temperature and 55°C for 40 times at the charge-discharge rate of 0.2C, Li1.3Al0.3Ti1.7(PO4)3-coated LiMn2O4 shows the capacity retentions of 98.2% and 93.9%, respectively, which are considerably higher than the values of 85.4% and 79.1% for the uncoated one. Both the capacity retention differences between Li1.3Al0.3Ti1.7(PO4)3-coated LiMn2O4 and LiMn2O4 cycling at room temperature and 55°C become larger with the increase of charge-discharge rate. When the charge-discharge rate reaches 2C, the capacity retention of LATP-coated LiMn2O4 becomes 8.4% higher than the uncoated LiMn2O4 for room temperature cycling, and it becomes 11.1% higher than the latter when cycled at 55°C. [ABSTRACT FROM AUTHOR]

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: The changes of Li+/vacancy arrangement in Li2+x Ti3O7 with a ramsdellite-type structure upon topo-electrochemical Li+ insertion were investigated by the entropy measurement of reaction combined with the Monte Carlo simulation. The experimental entropy measurement was conducted by potentiometric and calorimetrical methods. The obtained experimental data were in good accordance with simulated results. The results indicated that the ordered Li+/vacancy arrangement appeared at the compositions of x ∼0.45 and ∼1.20, where the observed entropy of reaction humped. The ordering of Li/vacancy were also indicated at the composition x ∼0.24 and 1.16 in Li2+x Ti3O7 by the Monte Carlo simulation which considers the most stable Li/vacancy arrangement in terms of Coulombic interaction. This substantial agreement between electrochemical behaviors and computational results confirmed that the formation of superstructure arising from Li/vacancy arrangement during the electrochemical reaction deeply related to the atomic level Coulombic interactions. [Copyright &y& Elsevier]

Abstract: A series of spinel Li4Ti5O12 samples were synthesized via a composite molten-salt method (CMSM) using the mixtures of LiCl and KCl with different L values (L is defined as the molar ratio of LiCl:KCl) as the reaction media. It is found that the melting point of the composite molten salt can effectively influence the formation of particles, and leads to different electrochemical performances of the as-prepare Li4Ti5O12. The investigations of X-ray diffraction (XRD), particle size distribution (PSD), Brunauer–Emmet–Teller (BET) surface area, and scanning electron microscopy (SEM) indicate that the as-prepared Li4Ti5O12 with L =1.5 is a pure phase, and has uniform homogeneous octahedral shape particles, rather narrow PSD, and high BET surface area. Electrochemical tests show that the optimized Li4Ti5O12 with L =1.5 has an initial discharge capacity of 169mAhg−1 and an initial charge–discharge efficiency of 94% at 0.2C rate, and achieves good rate performances from 0.2C to 5C. [Copyright &y& Elsevier]

Abstract: Li1.03Co0.15Mn1.82O4 powders as cathode materials used in lithium-ion battery were synthesized using an ultrasonic spray pyrolysis process. The prepared powders were heated at 750°C for different heating durations. As the heating time increased, the crystallinity of the powders significantly enhanced. The nanometered primary particles were aggregated into sphere-like secondary particles with a porous structure. The surface area of the heated samples decreased with an increase in the heating time. After the characteristics of electrochemical performance, the powders heated for 4h exhibited improved properties. When the discharge rate was 60C, this sample revealed high capacity retention which was 87% with the reference of 0.1C. According to the results of high C-rate tests, the electrochemical characteristic of the prepared Li1.03Co0.15Mn1.82O4 powders were found to depend on not only the crystallinity but also the surface area. For preparing cathode materials with good rate capability, the crystallinity and surface area of the materials need to be well controlled. [Copyright &y& Elsevier]

Abstract: In this paper, flower-like spinel Li4Ti5O12 consisting of nanosheets was synthesized by a hydrothermal process in glycol solution and following calcination. The as-prepared product was characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction and cyclic voltammetry. The capacity of the sample used as anode material for lithium ion battery was measured. This structured Li4Ti5O12 exhibited a high reversible capacity and an excellent rate capability of 165.8mAhg−1 at 8C, indicating potential application for lithium ion batteries with high rate performance and high capacity. [Copyright &y& Elsevier]

Abstract: Pure LiFePO4 was synthesized by heating an amorphous LiFePO4. The amorphous LiFePO4 obtained through lithiation of FePO4·xH2O by using oxalic acid as a novel reducing agent at room temperature. FePO4·xH2O was prepared through co-precipitation by employing FeSO4·7H2O and H3PO4 as raw materials. X-ray diffraction (XRD), scanning electron microscopy (SEM) observations showed that LiFePO4 composites with fine particle sizes between 100nm and 200nm, and with homogenous sizes distribution. The electrochemical performance of LiFePO4 powder synthesized at 500°C were evaluated using coin cells by galvanostatic charge/discharge. The synthesized LiFePO4 composites showed a high electrochemical capacity of 166mAhg−1 at the 0.1C rate, and possessed a favorable capacity cycling maintenance at the 0.1C, 0.2C, 0.5C and 1C rate. [Copyright &y& Elsevier]

Abstract: One-dimensional alpha manganese dioxide (α-MnO2) nanorods synthesized by a hydrothermal route were explored as the starting material for preparing lithium manganese spinel LiMn2O4. Pure and highly crystalline spinel LiMn2O4 was easily obtained from α-MnO2 nanorods through a low-temperature solid-state reaction route, while Mn2O3 impurity was present along with the spinel phase when commercial MnO2 was used as starting material. The particle size of LiMn2O4 prepared from α-MnO2 nanorods was about 100nm with a homogenous distribution. Electrochemical tests demonstrated that the LiMn2O4 thus prepared exhibited a higher capacity than that prepared from commercial MnO2. Therefore, α-MnO2 nanorods are proved to be a promising starting material for the preparation of high quality LiMn2O4. [Copyright &y& Elsevier]

Abstract: LiFePO4/C composite cathode material was prepared by carbothermal reduction method, which uses NH4H2PO4, Li2CO3 and cheap Fe2O3 as starting materials, acetylene black and glucose as carbon sources. The precursor of LiFePO4/C was characterized by differential thermal analysis and thermogravimetry. X-ray diffraction (XRD), scanning electron microscopy (SEM) micrographs showed that the LiFePO4/C is olivine-type phase, and the addition of the carbon reduced the LiFePO4 grain size. The carbon is dispersed between the grains, ensuring a good electronic contact. The products sintered at 700°C for 8h with glucose as carbon source possessed excellent electrochemical performance. The synthesized LiFePO4 composites showed a high electrochemical capacity of 159.3mAhg−1 at 0.1C rate, and the capacity fading is only 2.2% after 30 cycles. [Copyright &y& Elsevier]

Co-substituted α-Ni(OH)2 was synthesized by a novel microwave homogeneous precipitation method in the presence of urea. LiNi0.8Co0.2O2 cathode material was synthesized by calcining Co-substituted α-Ni(OH)2 precursor and LiOH·H2O at 900°C for 10 h in flowing oxygen. XRD, FTIR, FESEM and electrochemical tests were used to study the physical and the electrochemical performances of the materials. The results show that the prepared LiNi0.8Co0.2O2 compound has a good layered hexagonal structure. Moreover, the LiNi0.8Co0.2O2 cathode material demonstrates stable cyclability with a high initial specific discharge capacity of 183.9 mAh/g. The good electrochemical performance could be attributed to the uniform distribution of Ni2+ and Co2+ ions in the crystal structure and a minimal cation mixing in LiNi0.8Co0.2O2 host structure. [ABSTRACT FROM AUTHOR]

Abstract: MoO2 synthesized through reduction of MoO3 with ethanol vapor at 400°C was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Its electrochemical performance as an anode material for lithium ion battery was tested by cyclic voltammetry (CV) and capacity measurements. During the reduction process, the starting material (MoO3) collapsed into nanoparticles (∼100nm), on the nanoparticles remains a carbon layer from ethanol decomposition. Rate capacity and cycling performance of the as-prepared product is very satisfactory. It displays 318mAhg−1 in the initial charge process with capacity retention of 100% after 20 cycles in the range of 0.01–3.00V vs. lithium metal at a current density of 5.0mAcm−2, and around 85% of the retrievable capacity is in the range of 1.00–2.00V. This suggests the application of this type of MoO2 as anode material in lithium ion batteries. [Copyright &y& Elsevier]

Abstract: Spinel LiNi0.4Mn1.6O4 has been successfully synthesized by ultrasonic-assisted co-precipitation (UACP) method. The structure and physicochemical properties of this as-prepared powder compared with the LiNi0.4Mn1.6O4 synthesized by co-precipitation method were investigated by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge test in detail. XRD and SEM show that all samples have high phase purity, and ultrasonic process plays an important role in controlling morphology; FT-IR reveals that the Mn(III)–O stretching band at 511cm−1 has a red shift to 503cm−1, and the Mn(IV)–O stretching band at 612cm−1 has a blue shift to 622cm−1 because of the doped Ni. CV confirms that the LiNi0.4Mn1.6O4 sample (UACP) has bigger area of the reduction peaks than that of sample synthesized by co-precipitation method, indicating that the former has higher discharge capacity than that of the latter. Galvanostatic charge–discharge test indicates that the initial discharge capacities for the LiNi0.4Mn1.6O4 (UACP) at C/5 and 1C are 129 and 116mAhg−1, respectively. After 100 cycles, their capacity retentions are 94.6% and 85.3%, respectively. EIS indicates that LiNi0.4Mn1.6O4 samples synthesized by UACP method have smaller charge transfer resistance than that of samples synthesized by co-precipitation method corresponding to the extraction of Li+ ions. [Copyright &y& Elsevier]

Abstract: A Li2ZrO3 coating technique was successfully applied to layered lithium transition metal mixed oxide LiNi0.4Co0.2Mn0.4O2 to enhance its electrochemical performance using Zr(NO3)4·5H2O and CH3COOLi·2H2O as coating reagents. The existence of Li2ZrO3 coating layer was identified by X-ray diffraction (XRD), Environmental scanning electron microscopy (ESEM), Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The Li2ZrO3 shell decreased the exposed area of electrode core to electrolyte, and thus suppressed the dissolution of transition metal and side reaction between them. In addition, coating with Li2ZrO3 improved the ion transportation characteristics. As a result, an enhanced electrochemical performance in terms of discharge capacity, rate performance, and capacity retention were obtained, especially at higher temperature of 50°C. Analysis of electrochemical impedance spectra (EIS) showed that the coated material exhibited lower charge transfer resistance (R ct) with less variation during cycling, which indicated the electrode/electrolyte interface of coated material was more favorable and stable for electrochemical reaction. [Copyright &y& Elsevier]

Abstract: Nanoscaled tin (Sn) particles were embedded in the mesopores of hard carbon spherules (HCS) to form a composite anode material for lithium ion batteries. The structure of the obtained composite was characterized by X-ray diffraction (XRD) and the electrochemical performances were evaluated by galvanostatic cycling and cyclic voltammetry. It is found that embedding Sn nanoparticles into HCS not only results in a composite material with high-lithium storage capacity and capacity retention, but also increases the initial coulombic efficiency of the composite. Based on the infrared spectroscopic analysis, the enhanced initial coulombic efficiency is attributed to the nano-tin-induced decomposition of the ROCO2Li species in the solid electrolyte interphase (SEI) layer. [Copyright &y& Elsevier]

Abstract: In the process of Li+ intercalation–deintercalation, electron removal is accompanied simultaneously. Oxygen was found to compensate electron removal both in theoretical calculations and practical experiments. Chlorine addition to LiNi0.7Co0.3O2 was expected to exchange electrons in that Cl− was easier to lose electrons than O2−. LiNi0.7Co0.3O2−x Cl x was identified as a pure hexagonal lattice of α-NaFeO2 type by X-ray diffraction. X-ray photoelectron spectroscopy was used to analyze the influence of chlorine substitution on the oxidation state of transition-metal ions. Charge–discharge experiments and cyclic voltammetry confirmed that chlorine addition was an effective way to improve reversible capacity and structural stability in cycles. [Copyright &y& Elsevier]

Abstract: Computational and experimental work directed at exploring the electrochemical properties of tetrahedrally coordinated Mn in the +5 oxidation state is presented. Specific capacities of nearly 700mAhg−1 are predicted for the redox processes of Li x MnO4 complexes based on two two-phase reactions. One is topotactic extraction of Li from Li3MnO4 to form LiMnO4 and the second is topotactic insertion of Li into Li3MnO4 to form Li5MnO4. In the experiments, it is found that the redox behavior of Li3MnO4 is complicated by disproportionation of Mn5+ in solution to form Mn4+ and Mn7+ and by other irreversible processes; although an initial capacity of about 275mAhg−1 in lithium cells was achieved. Strategies based on structural considerations to improve the electrochemical properties of MnO4 n− complexes are given. [Copyright &y& Elsevier]

Abstract: We investigated the effect of CO2 on layered Li1+z Ni1−x−y Co x M y O2 (M=Al, Mn) cathode materials for lithium ion batteries which were prepared by solid-state reactions. Li1+z Ni(1−x)/2Co x Mn(1−x)/2O2 (Ni/Mn mole ratio=1) singularly exhibited high storage stability. On the other hand, Li1+z Ni0.80Co0.15Al0.05O2 samples were very unstable due to CO2 absorption. XPS and XRD measurements showed the reduction of Ni3+ to Ni2+ and the formation of Li2CO3 for Li1+z Ni0.80Co0.15Al0.05O2 samples after CO2 exposure. SEM images also indicated that the surfaces of CO2-treated samples were covered with passivation films, which may contain Li2CO3. The relationship between CO2-exposure time and CO3 2− content suggests that there are two steps in the carbonation reactions; the first step occurs with the excess Li components, Li2O for example, and the second with LiNi0.80Co0.15Al0.05O2 itself. It is well consistent with the fact that the discharge capacity was not decreased and the capacity retention was improved until the excess lithium is consumed and then fast deterioration occurred. [Copyright &y& Elsevier]

Abstract: Some polyanionic compounds, e.g. TiP2O7 and LiTi2(PO4)3 with 3D framework structure were proposed to be used as anodes of lithium ion battery with aqueous electrolyte. The cyclic voltammetry properties TiP2O7 and LiTi2(PO4)3 suggested that Li-ion de/intercalation reaction can occur without serious hydrogen evolution in 5M LiNO3 aqueous solution. The TiP2O7 and LiTi2(PO4)3 give capacities of about 80mAh/g between potentials of −0.50V and 0V (versus SHE) and 90mAh/g between −0.65V and −0.10V (versus SHE), respectively. A test cell consisting of TiP2O7/5M LiNO3/LiMn2O4 delivers approximately 42mAh/g (weight of cathode and anode) at average voltage of 1.40V, and LiTi2(PO4)3/5M LiNO3/LiMn2O4 delivers approximately 45mAh/g at average voltage of 1.50V. Both as-assembled cells suffered from short cycle life. The capacity fading may be related to deterioration of anode material. [Copyright &y& Elsevier]

Aluminum (Al) foil is widely used as a current collector in lithium ion batteries, EDLCs and other electrochemical devices, and its electrochemical behavior in electrolytes has great effect on the cycle performances and safety of the electrochemical devices. In this work, corrosion behavior of Al foil in 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids and its electrolytes containing LiTFSI as salt were studied using cyclic voltammogram method. It was found that a passive film was firmly formed on the surface of Al foil after the anodic polarization in BMI-BF4 compared to those in EMI-BF4 and PMI-BF4. In addition, anodic polarization research showed that the passive film on Al surface in BMI-TFSI did not well exist. A good passive film formed on the surface of Al foil in BMI-BF4 was not broken down until the potential was up to 94.58 V. Moreover, EDX and XPS analysis showed that F and O exist on the Al surface after the anodic polarization in BMI-BF4, which indicated that a passive film like AlF3 and Al2O3 may be formed on its surface. [ABSTRACT FROM AUTHOR]