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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]

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 structural and electrochemical effects of electrospun V2O5 with selected redox-inactive dopants (namely Na+, Ba2+ and Al3+) have been studied. The electrospun materials have been characterised via a range of analytical methods including X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area measurements and scanning and transmission electron microscopy. The incorporation of dopants in V2O5 was further studied with computational modelling. Structural analysis suggested that the dopants had been incorporated into the V2O5 structure with changes in crystal orientation and particle size, and variations in the V4+ concentration. Electrochemical investigations using potentiodynamic, galvanostatic and impedance spectroscopy analysis showed that electrochemical performance might be dependent on V4+ concentration, which influenced electronic conductivity. Na+- or Ba2+-doped V2O5 offered improved conductivities and lithium ion diffusion properties, whilst Al3+ doping was shown to be detrimental to these properties. The energetics of dopant incorporation, calculated using atomistic simulations, indicated that Na+ and Ba2+ occupy interstitial positions in the interlayer space, whilst Al3+ is incorporated in V sites and replaces a vanadyl-like (VO)3+ group. Overall, the mode of incorporation of the dopants affects the concentration of oxygen vacancies and V4+ ions in the compounds, and in turn their electrochemical performance.ᅟ [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 Li 2 SiO 3 -graphene composite is successfully synthesized through an easy hydrothermal method. The structures and morphologies of the produced samples are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrum, Brunauer-Emmett-Teller formalism, scanning electron microscope, transmission electron microscope, and electrochemistry methods. The result shows a well crystalline of the Li 2 SiO 3 -GE composite. The existence of graphene doesn’t change the crystalline of Li 2 SiO 3 . In addition, the Li 2 SiO 3 compound with an average diameter of 20 nm can be seen on the surface of graphene with uniform distribution. After the composite with graphene, the composite displays large surface area which ensures the well electrochemistry of the composite. Finally, the Li 2 SiO 3 -graphene composite delivers a high initial capacity of 878.3 mAh g −1 at 1C as well as a high recovery capacity of 400 mAh g −1 after 200 cycles. When charged and discharged at high rate, the Li 2 SiO 3 -doping graphene composite still exhibits a high specific capacity of 748.3 mAh g −1 (at 2C, and 576 mAh g −1 at 5C) and well cycling performance. The well synthesized composite possesses well structure and well electrochemistry performance. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) layers have been grown by spray-pyrolysis technique by using different spray pyrolysis deposition times (t sp ). AgNPs with ca. 80 nm mean diameter have been obtained for the lower t sp value, whereas as the spray-pyrolysis time value is increased, the Ag NPs diameters increased, reaching a AgNPs mean diameter of 190 nm for the highest t sp assayed value. X-ray diffraction patterns of the AgNPs layers samples exhibited a pure polycrystalline cubic silver phase, irrespective of the different t sp values. An optical visible light transmittance maximum of 60% at 550 nm has been observed for samples grown at t sp  = 5 s and 10 s. For higher t sp values this optical transmittance decreases. A semitransparent lithium ion battery (t sp  = 5 s) has been obtained, exhibiting an optical transmittance of about 49% at λ = 554 nm. Electrochemical measurements showed that the amount of lithium that reacted with the AgNPs layer was around 6 lithium/mol. By cycling a transparent Li/Ag-ITO single cell, good capacity retention was observed for the first ten cycles for which a high value of capacity is delivered: 706 A h kg −1 .When assembling this electrode in a full semitransparent battery, the electrochemical processes resulted to be reversible and the transparency preserved. [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]

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]

Recently, layered transition metal chalcogenides (LTMCs) have attracted great attention as anode materials for lithium ion batteries (LIBs). However, the volume expansion and structure instability of LTMCs during the lithiation and delithiation process still remains challenging. Herein, we report NbSe 3 nanobelts wrapped by reduced-graphene oxide (NbSe 3 @rGO) utilized as buffer layers with enhanced electrochemical performance. The X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy were used to probe features of the NbSe 3 @rGO. The NbSe 3 @rGO nanobelts as anode exhibit a discharge capacity of 300 mAh/g at the current density of 100 mAh/g after 250 cycles, several times higher than pure NbSe 3 nanobelts. The improved electrochemical performance of NbSe 3 @rGO is attributed to a buffer effect from the rGO, cushioning the volume-change-induced strain effect on the structure of NbSe 3 nanobelts during cycling. [ABSTRACT FROM AUTHOR]

Hierarchical CuCl with high economic value added (EVA) was successfully recycled with 85% recovery from the acid Cu printed circuit board (Cu-PCB) waste etchant via facile liquid chemical reduction. The micro-structure and morphology of the recycled hierarchical CuCl were systematically characterized in terms of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). Furthermore, the corresponding electrochemical performances as lithium ion battery (LIB) anode were also investigated in terms of galvanostatic charge/discharge, cyclic voltammetry (CV) and AC impedance. As expected, the recycled CuCl displayed a hierarchical tripod-like structure and large specific surface area of 21.2 m 2 /g. As the anode in LIB, the reversible discharge capacity was about 201.4 mAh/g even after 100 cycles, implying the satisfactory cycle performance. Clearly, the satisfactory results may open a new avenue to develop the sustainable industry, which is very important in terms of both the resource recovery and the environmental protection. [ABSTRACT FROM AUTHOR]

LiZnTiO/C nanocomposite has been synthesized using phenolic resin as carbon source in this work. The structure, morphology, and electrochemical properties of the as-prepared LiZnTiO samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), Raman spectroscopy (RS), galvanostatic charge-discharge, and AC impedance spectroscopy. SEM images show that LiZnTiO/C was agglomerated with a primary particle size of ca. 40 nm. TEM images reveal that a homogeneous carbon layer (ca. 5 nm) formed on the surface of LiZnTiO particles which is favorable to improve the electronic conductivity and inhibit the growth of LiZnTiO during annealing process. The as-prepared LiZnTiO/C composite with 6.0 wt.% carbon exhibited a high initial discharge capacity of 425 and 159 mAh g at 0.05 and 5 A g, respectively. At a high current density of 1 A g, 95.5 % of its initial value is obtained after 100 cycles. [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]

LiMn2O4 nanoparticles were successfully prepared using suitable dosage carbon nanotubles (CNTs) as a fuel through multiphase combustion synthesis. The effects of CNTs on the structure and electrochemical performance of LiMn2O4 were investigated. Rate performance test demonstrates that CNTs dosage greatly affect the electrochemical behaviour of LiMn2O4 and LiMn2O4 prepared by choosing suitable CNTs dosage (7%) as a fuel (C7%-LMO) shows high rate charge–discharge capability. X-ray diffraction results indicate that C7%-LMO has the smallest distortion degree in the crystal, compared to LiMn2O4 prepared without CNTs (C0%-LMO) and LiMn2O4 prepared with 10% CNTs (C10%-LMO). SEM results reveal that the average particle size of C7%-LMO is about 100 nm, which is the smallest among the three samples (C0%-LMO, C7%-LMO and C10%-LMO). This unique microscopic features guarantee C7%-LMO possesses the highest discharge capacity, the best cycling performance and the lowest charge transfer resistance among the three samples. [ABSTRACT FROM AUTHOR]

We report a facile process to synthesize Mo 0.91 W 0.09 S 2 /amorphous carbon composites with mean thickness of only 5 nm ultrathin nanosheets and their improved electrochemical performance as anode materials for lithium ion batteries (LIBs). Structural and morphological characterizations of the nanocomposite have been investigated by XRD, SEM and TEM. It was found the amorphous carbon to be well dispersed on the ultrathin nanosheets surface. Due to the increased interlayer distance and the synergistic effects between Mo 0.91 W 0.09 S 2 nanosheets and amorphous carbon, the as-prepared Mo 0.91 W 0.09 S 2 /C electrode deliveres exhibit a high Li capacity, an excellent rate capability, and a stable cycling performance, which suggests the Mo 0.91 W 0.09 S 2 /C composites as promising electrode material for LIBs. [ABSTRACT FROM AUTHOR]

Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 materials doped with different Zr contents are studied using X-ray diffractometry (XRD), energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), charge–discharge measurements, AC impedance spectroscopy as well as cyclic voltammetry. These results demonstrate that the element Zr is distributed uniformly in these materials. With the increase of Zr content, the lattice parameters a , c and lattice volume V become larger. The discharge cycling curves of cells show that Zr doping enhances cycle life compared with the undoped one. The sample with x =0.01 shows the highest capacity and best cycling performance, especially at high current density. The Li[Li 0.2 Mn 0.54− x /3 Ni 0.13− x /3 Co 0.13− x /3 Zr x ]O 2 ( x =0.01) delivers a capacity of 133.6 mA h g −1 (after 100 cycles) at the current density of 250 mA g −1 , corresponding to the capacity retention of 83.8%. The favorable performance of the doped samples could be attributed to its enhanced structural stability and Li + mobility. [ABSTRACT FROM AUTHOR]

A series of lithium borate added electrolyte compounds, x Li 3 BO 3 -(1− x )Li 3.5 Si 0.5 P 0.5 O 4 (0 ≤ x ≤ 0.2), are synthesized and characterized. This so-called LISICON electrolyte system is analyzed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), solid state nuclear magnetic resonance (ss-NMR), electrochemical impedance spectra (EIS), and direct current (DC) polarization methods. From 11 B MAS NMR spectra, it is demonstrated that a small fraction of boron exists in the form of BO 4 , while its majority settles at grain boundaries in the form of BO 3 , indicating that lithium borate glasses play a role as sintering assistant. This prominently increases the relative density of samples, and is beneficial to the ionic conductivity. Further results show that the electrical conduction of lithium borate added LISICONs is dominated by Li + ions, with a transference number of t Li + ≥ 0.996 and a corresponding ionic conductivity of about 6.5 × 10 −6 S cm −1 at room temperature, almost two times that of pristine Li 3.5 Si 0.5 P 0.5 O 4 . [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]

Li 2 MnO 3 is known to be electrochemically inactive due to Mn in tetravalent oxidation state. Several compositions such as Li 2 MnO 3 , Li 1.5 Al 0.17 MnO 3 , Li 1.0 Al 0.33 MnO 3 and Li 0.5 Al 0.5 MnO 3 were synthesized by a sol–gel Pechini method. All the samples were characterized with XRD, Raman, XPS, SEM, Tap density and BET analyzer. XRD patterns indicated the presence of monoclinic phase for pristine Li 2 MnO 3 and mixed monoclinic/spinel phases (Li 2 − x Mn 1 − y Al x + y O 3 + z ) for Al-substituted Li 2 MnO 3 compounds. The Al substitution seems to occur both at Li and Mn sites, which could explain the presence of spinel phase. XPS analysis for Mn 2p orbital reveals a significant decrease in binding energy for Li 1.0 Al 0.33 MnO 3 and Li 0.5 Al 0.5 MnO 3 compounds. Cyclic voltammetry, charge/discharge cycles and electrochemical impedance spectroscopy were also performed. A discharge capacity of 24 mAh g −1 for Li 2 MnO 3 , 68 mAh g −1 for Li 1.5 Al 0.17 MnO 3 , 58 mAh g −1 for Li 1.0 Al 0.33 MnO 3 and 74 mAh g −1 for Li 0.5 Al 0.5 MnO 3 were obtained. Aluminum substitutions increased the formation of spinel phase which is responsible for cycling. [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]

MoO 3 -coated Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 cathode materials were synthesized via using co-precipitation method and wet coating process, and their crystal structure and particle morphology were analyzed and observed by XRD, SEM and TEM. The electrochemical properties of these materials were investigated and analyzed by using charge-discharge tests and electrochemical impedance spectroscopy. The results showed that the surface coating on Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 cathode was composed of α-MoO 3 and Li 2 MoO 4 , and the electrochemical properties were improved after coated with MoO 3 thin films. The initial coulombic efficiencies increased from 71.2% to 79.3% when the MoO 3 content increased to 5 wt.%. Particularly, the 3 wt.% MoO 3 -coated Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 showed the highest capacity retention of 90.8% after 100 cycles, and possessed the excellent rate discharge performance. The electrochemical impedance spectroscopy (EIS) and cyclic voltammetric results demonstrated that the layered MoO 3 coating could restrain the increment of the charge transfer resistance and stabilize the active material structure during cyclic process. [ABSTRACT FROM AUTHOR]

A series of Li 2 Fe 1- x V x SiO 4 /C ( x = 0.00, 0.03, 0.05 and 0.07) composites have been synthesized via a refluxing-assisted solid-state reaction. XRD results confirm the monoclinic structure with space group P2 1 for Li 2 Fe 1- x V x SiO 4 /C compounds. TEM and Raman spectroscopy demonstrate V-doping can increase the graphitization degree of residual carbon. XPS confirms that V-incorporation does not change the divalent state of Fe, and the oxidation state of V in V-doped Li 2 FeSiO 4 /C is +3. Combined Ar-ion sputtering with XPS, it is found that V has been successfully doped into the crystal lattice of Li 2 FeSiO 4 . Electrochemical tests show that LFS/C-5 V delivers the highest initial discharge capacity of 220.4 mAh g −1 and the biggest Li-ion diffusion coefficient of 1.60 × 10 −11 cm 2 s −1 . In addition, the density functional theory (DFT) calculations predict that V-doping decreases the electronic band gap of Li 2 FeSiO 4 , thus leads to significant improvement in the electrical conductivity of Li 2 FeSiO 4 . The enhanced electrochemical performance can be attributed to the increased electronic conductivity, the decreased charge transfer impedance, and the improved Li-ion diffusion coefficient. Our results clarified the nature of V doping into Li 2 FeSiO 4 and demonstrated that V-doping is a promising approach to improve the electrochemical performance of Li 2 FeSiO 4 . [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]

Spherical layered Li 1+x Ni 0.5 Mn 0.5 O 2+δ (x = 0, 0.1 and 0.2) materials are synthesized by rheological phase reaction method. X-ray diffraction patterns reveal that the prepared materials have the α-NaFeO 2 structure with R-3m space group. The materials with different lithium contents show distinct differences in structure, particle morphology, electrochemical property and safety characteristics. When x = 0.1 and 0.2, excess lithium resides in the transition metal layer to form Li 2 MnO 3 -like structure. With lithium content increasing from 1.0 to 1.2, the initial discharge capacity and Coulombic efficiency are decreased, while capacity maintenance is improved. Mn ions are electrochemically activated in the charge–discharge process and has a contribution to the capacity when cycling in a voltage window of 2.5–4.5 V for x = 0.2, leading to a high discharge capacity of near 200 mAh g −1 and the excellent cycling performance (with no capacity decay after 100 cycles) at 20 mA g −1 . Electrochemical impedance spectroscopy shows that the appropriate excess of lithium can decrease charge transfer resistance obviously in the initial several cycles. The differential scanning calorimetric indicates that the generated heat of Li 1+x Ni 0.5 Mn 0.5 O 2+δ is increased with the increase of x. [ABSTRACT FROM AUTHOR]

The formation of the solid electrolyte interface (SEI) layer on the surface of the anode electrode of a lithium ion battery prevents further electrolyte decomposition reaction. However, at certain battery operating conditions, the SEI breakdown leading to more electrolyte decomposition reactions that form several species on the anode electrode surface. This paper focuses on the effect of battery potential and charge rate on the decomposition side reaction on the anode electrode of a lithium ion polymer battery, as a result of the breakdown of the SEI layer. The results from this study indicate that raising the state of charge (SOC) increases the rate of the electrolyte decomposition side reaction that resulted in formation of a thick deposit layer at the electrolyte/electrolyte interface. This deposit layer contains lithium that can no longer participate in the reversible electrochemical reaction. In addition, at high cycling potential and charge rates the amount of lithium in the graphite after complete cell discharge increased due to the entrapment of lithium in the graphite. The amount of irreversible capacity loss for the batteries cycled at high potential and current correlates with the amount of trapped lithium in the graphite and the growth of the deposit layer thickness at the electrode/electrolyte interface. [ABSTRACT FROM AUTHOR]

Cobalt sulfide-carbon composite powders were prepared by sulfidation of precursor powders obtained by spray drying. The precursor powders were composed of large particles with dimensions of several tens of micrometers and a hollow morphology with a thin-walled structure. The XRD pattern of the powders sulfidated at 200°C showed Co9S8as the main phase and CoS as the minor phase. However, the XRD patterns of the powders sulfidated at 300 and 400°C showed CoS as the main phase and Co9S8, Co3S4, and CoS2as the minor phases. The primary particle sizes of the powders sulfidated at 200, 300, and 400°C were 80, 190, and 230nm, respectively. Ultrafine cobalt sulfide crystals, a few nanometers in size, were uniformly distributed across the cobalt sulfide-carbon composite sheet. Dot-mapping images revealed that the carbon component was uniformly distributed throughout the composite powder. The optimum sulfidation temperature to obtain the composite powders with superior electrochemical properties was 300°C. The initial discharge and charge capacities of the composite powders sulfidated at 300°C at a current density of 1000mAg−1were 1089 and 878mA h g−1, respectively. The discharge capacity of the composite powders sulfidated at 300°C became stable at around 790mA h g−1for up to 70 cycles. [ABSTRACT FROM AUTHOR]

Solvothermal approach is used to synthesize LiMn0.9Fe0.1PO4 (LMFP) nanomaterial for Li-ion batteries (LIBs). Experimental parameters such as feeding sequences, reaction time and reaction temperature are discussed and the obtained LMFP are characterized by XRD, SEM and TEM. To understand the formation of LMFP, a reaction mechanism is proposed. The proposed mechanism indicates that the suitable concentration of MLi (M = Fe, Mn) antisite defect can improve the electrochemical performance of the material. The charge–discharge data of obtained LMFP shows that the LiMn0.9Fe0.1PO4 material synthesized at 180 °C for 4 h and then sintering with sucrose at 650 °C for 5 h under argon protection has the highest discharge capacity, which is 149.2 mAh g−1 at 0.1C rate. [ABSTRACT FROM AUTHOR]

Abstract: Li-excess Li[Li0.18Ni0.15Co0.15Mn0.52]O2 layered cathode material is prepared by the sol-gel method. The material is aged in a LiPF6 based electrolyte and then is subjected to a series of structural and electrochemical analyses. X-ray diffraction shows that aging in electrolyte does not change the C2/m ordering of the material crystal lattice. But the surface of the material is etched by the electrolyte which is confirmed by transmission electron microscope and Raman scattering. This causes dissolution of some transition metal elements (especially Ni and Co) and formation of a spinel-like surface layer. Also, some by-products resulted from the electrolyte decomposition are detected on the surface of the material. Electrochemical impedance spectroscopy shows that aging in electrolyte severely hinders the electrochemical kinetics of the material. Cyclic voltammetry indicates that the aged sample has large electrode polarization which prevents the oxygen loss process and the activation of Mn4+ ions. As a result, the discharge capacity of the aged sample continuously increases from 134 mAh g−1 to 215 mAh g−1 in the initial several cycles. [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]

Abstract: Li-rich layered oxide Li[Li0.2Mn0.54Ni0.13Co0.13]O2 is synthesized by combustion reaction using alcohol as both solvent and fuel. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that the oxide synthesized at 800 °C exhibits perfect crystallinity and lattice ordering, and has particle sizes of 50–150 nm. The layered oxide delivers an initial discharge capacity of 290.1 mAh g−1 at a current density of 20 mA g−1 after activation, and exhibits improved rate capability with high discharge capacities of 238.6 and 165.0 mAh g−1 at current densities of 200 and 2000 mA g−1 in the voltage range of 2.0–4.8 V, respectively. Low Li-ion diffusion coefficient of 1.07 × 10−14−1.01 × 10−16 cm2 s−1 is calculated by galvanostatic intermittent titration technique (GITT) during the initial discharge process, indicating that the improved rate capability is mainly attributed to the small particle sizes of the Li-rich oxide. [Copyright &y& Elsevier]

Abstract: The dynamic structural change of graphite during the electrochemical lithium intercalation at 1/3C was identified by an in situ high energy synchrotron XRD. Thanks to the fast data collecting detector and high energy X-ray beam of this characterization technique, the detailed structure change of graphite was monitored. Under a high current density, the voltage plateaus in discharge curve and superlattice peaks in XRD patterns were not observed. These results indicated that the dynamic lithium intercalation behavior was remarkably different from that described by the classical staging mechanism. Instead, a Li-riched phase as well as a series of intermediate phases for the x value in Li x C6 being larger than 0.5 were identified. This dynamic phenomenon was considered to be synergistically affected by the driving force of the intercalation reaction, van der Waals force between graphene layers and repulsive interaction between the intercalated Li specie. Basing on the experimental results, a dynamic mechanism was proposed. [Copyright &y& Elsevier]

Abstract: An electro-active LiCoO2 layer is coated onto the surface of LiNi0.8Co0.15Al0.05O2 powders via a molten salt method. The effect of calcination temperature, calcination time, flux content and coating amount on the electrochemical properties of the sample is investigated. The X-ray diffraction (XRD) analyses show that the LiCoO2 coating does not change the structure of LiNi0.8Co0.15Al0.05O2. The transmission electron microscopy (TEM) and scanning electron microscopy (SEM) measurements indicate that a uniform layer LiCoO2 particulate is coated on the surface of the LiNi0.8Co0.15Al0.05O2 particles. The electrochemical performance studies demonstrate that the 3.0wt.% LiCoO2-coated LiNi0.8Co0.15Al0.05O2 powders sintered at 800°C for 4h at weight ratio of KCl/LiNi0.8Co0.15Al0.05O2 =2 exhibit the best electrochemical properties, with an initial discharge capacity of 196.2mAhg−1 and capacity retention of 98.7% after 50cycles when cycled at a current density of 0.2C between 2.8 and 4.3V. Besides, these powders also show better rate capability and high-temperature performance than LiNi0.8Co0.15Al0.05O2. [Copyright &y& Elsevier]

Abstract: Spherical Li3V2(PO4)3/C (LVP/C) composites are successfully synthesized via two different spray-drying processes. XRD results reveal that some impurities, such as Na3V2(PO4)3, Li2NaV2(PO4)3 and Li4(P2O7), appear when sodium salt of carboxy methyl cellulose (CMC) acts as carbon source. SEM images show two different morphologies: solid spherical particles for LVP/C(A) prepared by adding CMC after pre-sintering, and hollow for LVP/C(B) prepared by adding CMC before pre-sintering. Compared to LVP/C(B), LVP(A) presents higher tap density and better electrochemical performance at any C-rate. Remarkably, another charge/discharge plateaus or anodic/cathodic peaks around 3.85V are detected for both LVP/C(A) and LVP/C(B) electrodes, which is attributed to the formation of Li3−x Na x V2(PO4)3 or some other electrochemically active composites containing Na+. CMC addition sequence has a significant influence on morphology of Li3V2(PO4)3. Furthermore, acting as carbon source and Na dopant, CMC shows a notable effect on electrochemical behavior of Li3V2(PO4)3 cathode material. [Copyright &y& Elsevier]

Abstract: The Li x Ni0.23Co0.12Mn0.65O2 electrode system with various compositions (x =1.19, 1.33, 1.46, 1.58) was synthesized from a metal oxide precursor synthesized by co-precipitation method. The XRD patterns of the prepared powders revealed a hexagonal α-NaFeO2 structure (space group: R-3m, 166) and the existence of a Li2MnO3 phase in the composite structure. In particular, the low Li content sample shows a three integrated structure (spinel, Li2MnO3, LiMO2) for a Li/Metal(Ni/Co/Mn) mol ratio of 1.2. Scanning electron microscopy showed that all the synthesized samples contained spherical agglomerates with a size of 8–10μm. Among the samples tested, Li1.46Ni0.23Co0.12Mn0.65O2 shows relatively high charge and discharge capacity for the first cycle is 287, 192.9mAhg−1, respectively. Also, charge transfer resistance was also significantly improved compare with other samples. [Copyright &y& Elsevier]

Abstract: LiNi0.5Mn0.5O2, a promising cathode material for lithium-ion batteries, is synthesized by a novel solution-combustion procedure using acenaphthene as a fuel. The powder X-ray diffraction (XRD) pattern of the product shows a hexagonal cell with a =2.8955Å and c =14.1484Å. Electron microscopy investigations indicate that the particles are of sub-micrometer size. The product delivers an initial discharge capacity of 161mAhg−1 between 2.5 and 4.6V at a 0.1C rate and could be subjected to more than 50 cycles. The electrochemical activity is corroborated with cyclic voltammetric (CV) and electrochemical impedance data. The preparative procedure presents advantages such as a low cation mixing, sub-micron particles and phase purity. [Copyright &y& Elsevier]

Abstract: Olivine lithium manganese phosphate (LiMnPO4) becomes research focus because of its high energy density and improved thermal stability. However, its application in lithium ion batteries suffers severely from poor electrochemical activity due to low conductivity and structural instability upon the charge and discharge process. By applying a high-energy ball-milling method we succeed in improving the capacity delivery and rate capability. LiMnPO4 materials ball-milled without or with acetylene black are able to deliver a high capacity of 135 and 127mAhg−1, respectively, more than 50% greater than the pristine one. Particularly, the latter also shows an improved discharge plateau and stable cyclability. High-energy synchrotron radiation X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, laser particle analysis, and galvanostatic charge and discharge are employed to understand the effect of ball-milling on the LiMnPO4 material. [Copyright &y& Elsevier]

Abstract: Fine-sized, well-crystallized LiMnPO4 and two Cu-doped derivatives (2% and 5% Cu2+ doping) are readily prepared via a hydrothermal route. X-ray diffraction (XRD) combined with structural analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area analysis, and galvanostatic charge–discharge tests are applied to characterize these materials. The structure analysis shows that only a negligible amount of Cu2+ ions (0.2%) occupy the Li sites in the 2% Cu-doped material, while a considerable amount of Cu2+ ions (1.8%) occupy the Li sites in the 5% Cu-doped one. The electrochemical tests show that the 2% Cu-doped LiMnPO4 displays an improved electrochemical performance compared with the undoped LiMnPO4, while the 5% Cu-doped LiMnPO4 exhibits a decreased activity. [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: Spherical spinel LiMn2O4 particles were successfully synthesized from a mixture of manganese compounds containing commercial manganese carbonate by sintering of the spray-dried precursor. Different preparation routes were investigated to improve the tap density and to enhance the electrochemical performance of LiMn2O4. The structure and morphology of the LiMn2O4 particles were confirmed by X-ray diffraction (XRD) and scanning electron microscopy. The results showed that hollow spherical LiMn2O4 particles could be obtained when only commercial MnCO3 was used as the manganese source. These particles had a low tap density (ca.0.8g/cm3). Perfect micron-sized spherical LiMn2O4 particles with good electrochemical performance were obtained by spray-drying a slurry composed of MnCO3, Mn(CH3CHOO)2 and LiOH, followed by a dynamic sintering process and a stationary sintering process. The as-prepared spherical LiMn2O4 particles comprised hundreds of nanosize crystal grains and had a high tap density(ca. 1.4g/cm3). The galvanostatic charge–discharge measurements indicated that the spherical LiMn2O4 particles had an initial capacity of 121mAh/g between 3.0 and 4.2V at 0.2C rate and still delivered a reversible capacity of 112mAh/g at 2C rate. The retention of capacity after 50cycles was still 96% of its initial capacity at 0.2C. All the results showed that the as-prepared spherical LiMn2O4 particles had an excellent electrochemical performances. The methods we used for preparing spherical LiMn2O4 are energy-saving and suitable for industrial application. [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: Conductive carbon has been coated on the surface of LiNi0.5Mn1.5O4 cathode material by the carbonization of sucrose for the purpose of improving the rate performance. The effect of carbon coating on the physical and electrochemical properties is discussed through the characterizations of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), cycling and rate tests. Results demonstrate that the carbon coating can greatly enhance the discharge capacity, rate capability and cycling stability of the LiNi0.5Mn1.5O4 without degrading the spinel structure. The sample modified with 1wt.% sucrose displays the best performance. A large capacity of 130mAhg−1 at 1C discharge rate with a high retention of 92% after 100 cycles and a stable 114mAhg−1 at 5C discharge rate can be delivered. The remarkably improved rate properties of the carbon-coated samples are due to the suppression of the solid electrolyte interfacial (SEI) layer development and faster kinetics of both the Li+ diffusion and the charge transfer reaction. [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: 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: 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]

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]

A nano-crystalline MgO coating was formed on the surface of LiCoO2 particle via a sol–gel method. MgO coating can improve the cycling stability of LiCoO2 significantly. After the 40th cycle a discharge capacity of more than 120 mAh/g was remained for 1 mol% MgO-coated LiCoO2, while only 13 mAh/g for pristine LiCoO2 when both charged up to 4.7 V. During heat treatment and charge/discharge process, Mg2+ in coatings will diffuse into LiO2-layers of LiCoO2, which does not cause any detectable shift in X-ray diffractometer (XRD) peak positions, but does impact the XRD peak intensity due to the aberrance of (0 0 3) plane. Mg2+ ions existing in LiO2-layers will stabilize the lattice structure of LiCoO2, hence improve the cycling performance of LiCoO2 cathode. More MgO coating on LiCoO2 is detrimental to the electrochemical properties of LiCoO2 cathode, probably due to the electrochemical inactivity of MgO particles. [Copyright &y& Elsevier]

A structural relaxation study has been carried out on Lix(Ni0.874Co0.090Al0.036)O2 after the electrochemical lithium was extraction down to x = 0.12. These relaxation analyses have been carried out using X-ray diffraction coupled with the Rietveld analysis, assuming two phases (H2 and H3) and co-existence with R 3 ¯ m symmetry. The mole fraction of the H3 phase seemed not to vary largely during the relaxation time. As for the lattice constants, both H2 and H3 phases gradually increased the a-axis with the relaxation time. On the other hand, H2 and H3 phases increased and decreased the c-axis, respectively. The results are compared with that of previously reported Ni-rich NCA. [ABSTRACT FROM AUTHOR]