Lithium Zinc Titanate Research Articles

Chitosan oligosaccharides: A novel and efficient water soluble binder for lithium zinc titanate anode in lithium-ion batteries

Chitosan oligosaccharides (COS) as a new, environmentally and water-based organic compound, is firstly applied as the electrode binder for Li2ZnTi3O8 electrode in lithium-ion batteries. Compared with conventional polyvinylidene fluoride (PVDF) binder, the COS binder is used for Li2ZnTi3O8 electrode significantly improves the electrochemical performances in terms of the first Columbic efficiency, cycling behavior, rate capability and long life cycle. At 0.1Ag−1, the initial discharge capacity of 215.6mAhg−1 can be obtained for Li2ZnTi3O8 with COS binder system and the Columbic efficiency is as high as 93.6%, which are apparently better than PVDF binder system. Moreover, 66.1mAhg−1 can be remained after 1000 cycles and the retention is 33.6% for COS binder system, while the PVDF binder system has only 37.9mAhg−1 (22.8%). In addition, the cycling stability of Li2ZnTi3O8 electrode has been improved after using COS as binder. The elevated electrochemical performances of Li2ZnTi3O8 electrode with COS binder system can be ascribed to the characters of COS binder, which not only provide numerous hydroxyl groups formed strong hydrogen binds with both active materials and copper current collector, but also suppress swelling of electrode with electrolyte solution.

Lithium cobalt oxide coated lithium zinc titanate anode material with an enhanced high rate capability and long lifespan for lithium-ion batteries

LiCoO2 coated Li2ZnTi3O8 is synthesized by a preliminary formation of Li2ZnTi3O8 by facile solid state reaction and a following coating process with LiCoO2 nano layer via a wet chemical process followed by heat treatment. The structure and electrochemical property of the as-prepared samples have been characterized comprehensively. A thin LiCoO2 layer with a thickness of about 2nm is uniformly coated on the surface of active particles, which does not affect the crystal structure and space group. After LiCoO2 surface modification, high discharge capacities of 192.1, 163.7, 108.2mAhg−1 with capacity retention of 99.1, 92.3, 71.4% are obtained at 1.0, 2.0, 3.0Ag−1 after 100 cycles for the coated composite, respectively, which are obviously larger than those of un-coated sample. Besides, the discharge capacity and cyclic stability of Li2ZnTi3O8 after 1000 cycles have been enhanced after coating. Cyclic voltammograms and electrochemical impedance spectroscopy measurements prove that the LiCoO2 coating can dramatically decrease polarization and reduce the charge transfer resistance during repeated Li+ intercalation/de-intercalation process. The improved electrochemical properties of LiCoO2 coated Li2ZnTi3O8 are attributed to small particle sizes, large packed holes, high surface area and better electronic conductive.

Ionic Conductivity of Li<sub>2</sub>ZnTi<sub>3</sub>O<sub>8</sub> Single Crystal

Single crystals of lithium zinc titanate (Li2ZnTi3O8) were grown in a double-mirror type optical floating-zone furnace for the first time. Single crystals were characterized by X-ray powder diffraction and Laue measurements. The ionic conductivity of the single crystals was measured in the temperature range of 400–700 K. Below 600 K, the ionic conductivity of the single crystal is one to two orders of magnitude higher than that of polycrystalline Li2ZnTi3O8. In the temperature range of 550–600 K, the temperature dependence of the ionic conductivity shows non-Arrhenius behaviour.

Synthesis and characterization of Li2ZnTi3O8 spinel using the modified polymeric precursor method

In this work we report the synthesis procedure, crystallographic, structural and magnetic properties of the Li2ZnTi3O8 spinel obtained using a modified polymeric precursor method. This synthesis method generates very reactive and property-controlled nanoparticles. The samples were characterized using X-ray powder diffraction (XRD) associated to the Rietveld refinement method, thermogravimetric analysis (TG), specific surface area, scanning electron microscopy (SEM) and magnetic susceptibility measurements.The phase formation temperature of the lithium zinc titanate spinel was observed to decrease due to the homogeneity and highly controlled nanometric particle size.