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Spinel LiVTiO 4 /C compound is prepared via a facile sol–gel method. The structure and morphology of LiVTiO 4 /C are investigated by X-ray diffraction (XRD), scanning electronmicroscopy (SEM), and transmission electron microscopy (TEM). The results indicate that the LiVTiO 4 /C has a carbon coating layer ranging between 2 and 3 nm. Besides, the existence of VO 2 improves the conductivity to some extent. The electrochemical properties of LiVTiO 4 /C as an anode material for lithium-ion battery are investigated for the first time. The synthesized LiVTiO 4 /C material exhibits a high charge capacity of 231.6 mA h g − 1 after 50 cycles at 0.02 A g − 1 , with a capacity retention ratio of 96.5%. The excellent reversible capacity and excellent cycling stability indicate that the LiVTiO 4 /C composite has a great potential application in lithium-ion battery. [ABSTRACT FROM AUTHOR]

In situ nickel/carbon coated Li 4 Ti 5 O 12 has been synthesized successfully via a facile sol-gel method with chitosan serving as chelating agent and carbon source. The as-prepared samples are tested by different physical and electrochemical methods. The results of SEM and TEM indicate that the Ni/C layer was successfully coated on the surface of Li 4 Ti 5 O 12 with the thickness of 2–3 nm. Furthermore, the Li 4 Ti 5 O 12 @Ni/C composite shows excellent rate capability and cycling stability. A large charge capacity of 237.3 mAh g −1 can be remained after 100 cycles with the current of 0.1 A g −1 between 0.02–3.0 V, which is close to its theoretical capacity (∼262 mAh g −1 ). Even at the current of 4.0 A g −1 , it still delivers a quite high charge capacity of 186.5 mAh g −1 after 100 cycles, with no significant capacity fading. Additionally, the results of EIS reveal that the Li 4 Ti 5 O 12 @Ni/C electrode has faster lithium-ion diffusivity and less resistance compared with pure Li 4 Ti 5 O 12 . The remarkable improvement of the electrochemical properties should be attributed to the Ni/C coating layer, which acts as an effective conductor and a protective material against side reactions with electrolyte. [ABSTRACT FROM AUTHOR]

Amorphous titanium oxides have emerged as potential substitutable anode materials for high-rate lithium-ion batteries with the merits of abundant lithiation sites and accessible short ion diffusion channels. However, extreme differences in electrochemical properties and a poor understanding of the structure-property relationship for amorphous titanium oxides prepared via various synthetic strategies, hinder their further application. We designed amorphous titanium oxides with a unique structure and provided a moderate understanding of how titanium vacancies /open pore channels affect lithium ions (Li+) transportation behaviors in the amorphous titanium oxides. Galvanostatic charge/discharge curves and cyclic voltammetry (CV) tests revealed that two-step pseudo-capacitive behaviors, different from the diffusion-controlled process in anatase TiO 2 , mainly control Li+ insertion/extraction capacity in amorphous titanium oxides. Surface chemistry and structure analysis with FTIR and 1H solid-state NMR reveal that amorphous titanium oxides are rich in protons bonded to bridging hydroxyl groups. Density functional theory (DFT) calculations imply that the titanium vacancies and open channels promote lithium insertion/de-insertion processes with the two-step storage behaviors, favoring the pseudo-capacitive type in the amorphous titanium oxides. Our study may provide greater insight into the lithiation behaviors in amorphous materials and helpful guidelines in designing other high-capacity amorphous-oxide electrode materials for alkali-ion batteries. Atomic Scale Lithiation Mechanism of Anatase and Amorphous Titanium Oxides. [Display omitted] [ABSTRACT FROM AUTHOR]

Li 2 MoO 4 modified Li 4 Ti 5 O 12 /C anode material has been synthesized by a ball-milling assisted rheological phase reaction method. The structures, morphologies and electrochemical properties of the as-prepared materials have been analyzed by different physical and electrochemical methods. The results show that the amorphous carbon is successfully coated on the surface of Li 4 Ti 5 O 12 nanoparticles with partial doping of Mo 6+ into the Li 4 Ti 5 O 12 structure. Electrochemical results indicate that Li 2 MoO 4 modified Li 4 Ti 5 O 12 /C samples deliver improved rate capability and decreased charge transfer resistance. Among the investigated samples, the one with 5 wt % Li 2 MoO 4 sample exhibits the optimal electrochemical properties and it shows a large capacity of 167.5 mAh g −1 at 1C rate, which is close to its theoretical capacity. Even at 10C, its charge capacity is up to 137.5 mAh g −1 with a high capacity retention of 92.5% after 200 cycles. The excellent electrochemical properties should be attributed to the improvement of electrochemical kinetics by the synergistic employment of reducing particle size, partial Mo 6+ doping and Li 2 MoO 4 /C modification. [ABSTRACT FROM AUTHOR]