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Zn2TiO4 spheres are fabricated via a simple hydrothermal strategy combined with subsequent heating treatment of 600, 700, and 800 °C, respectively. All the as‐synthesized Zn2TiO4 spheres are assembled by many small nanospheres with a particle size of 20–100 nm. The compactness of Zn2TiO4 spheres is continuously enhanced as the temperature rises from 600 to 800 °C. Additionally, compared with the Zn2TiO4 calcined at 700 and 800 °C samples, the Zn2TiO4 sintered at 600 °C sample exhibits the best electrochemical performance, and it can deliver the high discharge specific capacities of 405, 269, 223, 193, 173, and 166 mAh g–1 at current densities of 50, 100, 200, 300, 400, and 500 mA g–1, respectively. Simultaneously, it also displays the excellent cyclic performance with a high reversible charge (discharge) capacity of 245.8 (247.7) mAh g–1 after 300 cycles at the current density of 200 mA g–1. The results demonstrate that the as‐prepared ZnTiO4 spheres sintered at 600 °C will be expected to be a new anode material of lithium ion batteries. [ABSTRACT FROM AUTHOR]

Na2Li2Ti6O14 particles were prepared by a simple solid-state process, and then g-C3N4-coated Na2Li2Ti6O14 composites were constructed by a facile solution route for the first time. The g-C3N4-coated Na2Li2Ti6O14 multicomponent composites because of their unique architecture as negative materials for Li-ion batteries can be expected to exhibit a significantly improved cycling stability and reversible capacity even at high rates. g-C3N4 (5 wt%)-coated Na2Li2Ti6O14 shows a discharge (charge) capacity of 184.4 (184.3) mA h g−1 at 500 mA g−1 after 100 cycles, which is larger than that of pristine Na2Li2Ti6O14 with a discharge (charge) capacity of 122.8 (122.0) mA h g−1. The use of g-C3N4 with a carbon framework containing abundant nitrogen provides more active sites and surface defects for redox reactions and Li-ion transport. The g-C3N4 coating decreases the impedance between the electrolyte and Na2Li2Ti6O14 and enhances the charge transfer, ionic conductivity and diffusion ability of Li ions of Na2Li2Ti6O14. This work offers an efficient way to design high-performance Na2Li2Ti6O14-based materials for advanced lithium ion battery, and g-C3N4 (5 wt%)-coated Na2Li2Ti6O14 shows an enormous potential as a negative material for next generation Li-ion batteries with excellent performance. [ABSTRACT FROM AUTHOR]

The graphene oxide-coated SnO2-Li1/3Co1/3Mn1/3O2 (GO-SnO2-NCM) cathode material was successfully synthesized via a facile wet chemical method. The pristine NCM and GO-SnO2-NCM were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results showed that the double-coating layer did not destroy the NCM crystal structure, with multiple nano-SnO2 particles and GO uniformly covering the NCM surface. Electrochemical tests indicated that GO-SnO2-NCM exhibited excellent cycling performance, with 90.7% capacity retention at 1 C after 100 cycles, which was higher than 74.3% for the pristine NCM at the same cycle. The rate capability showed that the double-coating layer enhanced surface electronic–ionic transport. Electrochemical impedance spectroscopy results confirmed that the GO-SnO2-coating layer effectively suppressed the increased electrode polarization and charge transfer resistance during cycling. [ABSTRACT FROM AUTHOR]

Submicron-sized NiV 3 O 8 powder was prepared by solid-state reaction method. A mixture of NiO, V 2 O 5 and home-made VO 2 (B) was used as starting material. The phase purity, structures, morphologies of the prepared powders were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and X-ray photo-electron spectrometry (XPS), respectively. The results show that the as-prepared NiV 3 O 8 material is highly crystalline and a single phase. The charge-discharge experiments were performed to investigate the electrochemical properties of NiV 3 O 8 powder. NiV 3 O 8 cathode delivers an initial discharge capacity of 286.6 mAh g −1 and still remains at 241 mAh g −1 after 30 cycles in the voltage of 1.5–4.2 V. The rate performance and EIS results indicate that the as-prepared electrode material has very good structural stability upon cycling after electrode conditioning by an initial charge and discharge. [ABSTRACT FROM AUTHOR]

Abstract: The cathode-active materials LiMn2O4LiZn0.05Mn1.95O4(PO4)x (x=0, 0.025, 0.05) were synthesized via traditional solid state reaction. Ball milling technique and citric acid additive were employed to obtain the as-prepared products with nanoscaled particles, which were characterized by various methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and charge–discharge studies. Doping the Mn spinel with Zn2+ ions can increase the overall Mn oxidation state and minimize Jahn–Teller distortion. It is shown that LiZn0.05Mn1.95O3.96(PO4)0.025 and LiZn0.05Mn1.95O3.99 samples have almost identical discharge capacities of about 114mAh·g−1 in the first cycle and the capacity retention rate of LiZn0.05Mn1.95O3.96(PO4)0.025 is superior to that of LiZn0.05Mn1.95O3.99 and the undoped LiMn2O4. The results demonstrate that doped zinc and phosphate can stabilize the structural integrity of the spinel host by suppressing the Jahn–Teller distortion and also provide short distance for Li+ diffusion upon cycling. [Copyright &y& Elsevier]

Abstract: Compounds LiNi1−x Sb x O2 (x=0, 0.1, 0.15, 0.2, 0.25) were synthesized by the two-step calcination method. The structural and morphological properties of the products were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD analysis confirms that the uniform solid solution has been formed in the as-prepared compounds without any impurities. It is shown that the crystal lattice parameters (a, c) of the Sb-doped compounds are bigger than those of pure LiNiO2 and the Sb-doped compound with x=0.2 consists of spherical-like nanoparticles with a mean grain size of 50nm. The electrochemical performances of as-prepared samples were studied via galvanostatic charge–discharge cycling tests. The compound with x=0.2 exhibits excellent capacity retention during the charge–discharge processes due to its reinforced structural stability, and a discharge capacity of 102.4mAh/g is still obtained in the voltage range of 2.5–4.5V after 20 cycles. Thermal analysis further confirms that the structural stability of LiNi0.8Sb0.2O2 is superior to that of pure LiNiO2. [Copyright &y& Elsevier]

Abstract: The Li–V–O composite (n Li:n V =1:3.5) was synthesized by a hydrothermal method and post-treated at 300°C. XRD analysis confirms that the composite is a binary LiV3O8–V2O5 composite system with the formula of 0.8LiV3O8·0.2V2O5. The composite consists of small laminar nanocrystallites with numerous cavities between the stacked laminar nanocrystallites, which can provide good channels for Li+ transfer during charge–discharge cycling. The initial discharge capacities of LiV3O8 and 0.8LiV3O8·0.2V2O5 samples were 276 and 365mAh/g after 20 cycles, the discharge capacities of the two samples were 197.6 and 304mAh/g, respectively. Smaller capacity loss indicates that the capacity retention of the composite is superior to that of bare LiV3O8 cathode. [Copyright &y& Elsevier]

In this work, a reasonable strategy for the construction of Li 2 ZnTi 3 O 8 @Na 2 WO 4 composite was employed to promote the Li storage performances of Li 2 ZnTi 3 O 8. The Li 2 ZnTi 3 O 8 @Na 2 WO 4 composites (5, 10, and 15 wt%) were then prepared by a solution dispersion method. The introduction of Na 2 WO 4 does not change the structures of the samples and they show similar morphologies with particle sizes from 100 to 200 nm. Suitable amount of Na 2 WO 4 modification effectively improves the electrochemical performance of Li 2 ZnTi 3 O 8. Li 2 ZnTi 3 O 8 @Na 2 WO 4 composites (0, 5, 10, and 15 wt%) deliver the discharge/charge capacities of 137.4/136.4, 164.2/162.3, 189.2/188.1, and 154.5/153.3 mAh g−1 at 0.5 A g−1 after 100 cycles, respectively. Li 2 ZnTi 3 O 8 @Na 2 WO 4 composites (10 wt%) has the highest reversible capacities among all samples. The Na 2 WO 4 shell with an excellent electronic conductivity can reduce electrode polarization, decrease the charge transfer resistance, enhance the Li-ion diffusion coefficient of Li 2 ZnTi 3 O 8 , and then improve the electrochemical kinetics of composites. In addition, the formation of Ti–O bonds at the interface can be helpful for the stabilization of the composite, being beneficial for the improvement of their cycling stabilities. These results reveal that Na 2 WO 4 coating is a facile and effective strategy to promote the Li storage performance of Li 2 ZnTi 3 O 8. [ABSTRACT FROM AUTHOR]

Li 2 ZnTi 3 O 8 @ α -Fe 2 O 3 composites have been successfully prepared by a facile hydrothermal process. Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites show similar irregular spherical morphologies like Li 2 ZnTi 3 O 8 and relatively smaller particle sizes than pristine Li 2 ZnTi 3 O 8. Among all Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites, Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composite (5 wt%) exhibits the best electrochemical properties. Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composite (5 wt%) delivers a reversible charge capacity of 184.8 mAh g−1 even at 1000 mA g−1 after 500 cycles, while pristine Li 2 ZnTi 3 O 8 only delivers a reversible charge capacity of 110.7 mAh g−1. The strong covalent bonds between Li 2 ZnTi 3 O 8 and α-Fe 2 O 3 will be formed, which is beneficial for the reduction of interfacial energy and thus helpful for the stabilization of the composite. Because of the special synergistic effect of the multi-phase interface, Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites not only possess the advantages of single components but also show novel and attractive performances, such as the enhanced ionic conductivity, reduced interfacial charge transfer impedance, improved migration rate of lithium ions, and the enhancement of the rate performance and reversible capacity. The as-prepared Li 2 ZnTi 3 O 8 /α-Fe 2 O 3 composites reveal important potentials as anode materials for next-generation rechargeable Li-ion batteries, and this work also offers an effective strategy to design high performance lithium storage materials for advanced lithium-ion batteries. [ABSTRACT FROM AUTHOR]

In order to enhance the electrochemical performance of Na 2 Li 2 Ti 6 O 14 anode material, biomass carbon was induced for promoting poor electrical conductivity and Li + diffusion coefficient of Na 2 Li 2 Ti 6 O 14. Na 2 Li 2 Ti 6 O 14 @C composites were synthesized by a solvothermal method, which showed a spherical morphology composed of nanoparticles with a particle size of 2–5 μm. The result of electrochemical tests show that biomass carbon decorated Na 2 Li 2 Ti 6 O 14 anode material can improve electrochemical performance of pristine Na 2 Li 2 Ti 6 O 14 material. Meanwhile, the Na 2 Li 2 Ti 6 O 14 @C (5 wt%) exhibits the highest specific capacity of 195 mAh g−1 at 500 mA g−1 among all samples. Na 2 Li 2 Ti 6 O 14 @C (5 wt%) exhibits an excellent rate performance with specific capacities of 283.3, 244.7, 226.6, 212.3 and 193.4 mAh g−1 at the current density 50, 100, 200, 300 and 500 mA g−1, respectively. The porous spherical structure combined with high conductive biomass carbon shell shows an enhanced electron conductivity, reduced charge transfer resistance and increased Li-ion diffusion coefficient. Hence, the enhanced electrochemical performance of Na 2 Li 2 Ti 6 O 14 @C can be attributed to the constructed elaborate architecture and component. [Display omitted] • The biomass carbon-coated NLTO composite together with unique architecture was prepared for the first time. • The biomass carbon-coated NLTO composite indicates high cycling stability and reversible capacity even at high rates. • The biomass carbon-coated NLTO composite indicates a potential application prospect. [ABSTRACT FROM AUTHOR]

Abstract: The porous hematite (α-Fe2O3) nanorods, having diameters of 30–60nm, were prepared through thermal decomposition of FeC2O4·2H2O nanorods that were readily synthesized through poly(vinyl alcohol)-assisted precipitation process. Compared to the commercial α-Fe2O3 powders in submicrometer sizes, the porous α-Fe2O3 nanorods, as an electrode material in lithium-ion batteries, exhibited significantly enhanced rate capability due to their nanorod shape and porous structure. When discharging at 0.1C (1C=1005mA/g) and charging at different rates (0.1C, 0.5C, and 1C), the porous α-Fe2O3 nanorods could deliver a capacity of over than 1130mAh/g; while cycling at 1C rate, the nanorods could maintain a discharge capacity as high as 916mAh/g after 100cycles. [Copyright &y& Elsevier]