Lithium Zinc Chloride Nanoparticles by Simple Co-Precipitation Method
Received Date: Aug 17, 2018 / Accepted Date: Aug 24, 2018 / Published Date: Aug 31, 2018
Keywords: LiZnCl4; Co precipitation; XRD; Optical studies
Nanoparticulate electrodes, such as Li2ZnCl4, have unique advantages over their microparticulate counterparts for the applications in Li-ion batteries because of the shortened diffusion path and access to nonequilibrium routes for fast Li incorporation, thus radically boosting power density of the electrodes [1-3]. Li intercalation occurs locally in a single nanoparticles of such materials remains unresolved because real-time observation at such a fine scale is still lacking which was well agreement with the JCPDS file number 86-1806. Many researchers reported visualization of local Li intercalation via solid-solution transformation in individual Li2ZnCl4 nanoparticles, enabled by probing sub-angstrom changes in the lattice spacing in situ . The real-time observation reveals inhomogeneous intercalation, accompanied with an unexpected reversal of Li concentration at the nanometer scale. The origin of the reversal phenomenon is elucidated through phase-field simulations, and it is attributed to the presence of structurally different regions that have distinct chemical potential functions. The findings from this study provide a simple perspective on the structural and morphological properties of synthesized Li2ZnCl4 nanoparticles by using sol-gel method [4-6].
Materials and Methods
For synthesis of nano composites using analytical grade I molar solution in 25 ml of Lithium chloride MW (42.394 gm/mol) (1.0599 gm) with 0.05 molar solution of Zinc chloride Molar mass (136.286 g/ mol) (0.17 gm) and H2O2 liquid (10 vol%) was stirred with total volume of 25 ml deionised water without further purification. By using magnetic stirrer the above solution was stirred for one hr continuously. Milk white solution was placed on the hot plate and raise the temperature above 100°C until we get the fine powder. It is very simple co-precipitation method to prepare the particles. Then the prepared nano composites were oven dried at 60°C for 2 hours and finally annealed to the temperatures of 200°C for continuous 2 hours under static air atmosphere [7,8]. The as prepared and annealed nano composites were taken for further characterisation.
The nanoparticles confirmation were carried out by powder X-ray diffraction (XRD) X-ray diffractometer (XRD) with monochromation CuKα target (1.5406A°) at a scan rate of 20/min. Scanning electron microscope (SEM) work on the calcined powders were performed under Scanning Electron Microscope Cambridge 53400N. The photoluminescence (PL) spectra were obtained from fluorospectrophotometer (Cary Eclipse) by using 280 nm line of Xe lamp as excitation source.
Results and Discussion
Structural studies (XRD)
The structure of the crystallites of the thin films developed is to be studied to assess whether the films could be used for the intended applications. The X-ray Diffraction (XRD) technique is a very powerful tool for the crystal structure determination. X-rays are a form of electromagnetic radiation, which can be diffracted by the atom bearing planes of a crystal. Using X-ray diffraction, information about the crystal structure can be obtained from the positions and intensities of the diffracted beams. Taking that the scattering centers (atoms) are located in a set of crystal planes whose directional properties are described by the Miller indices hkl, the distance between the planes (dhkl) can be related to the scattering angle (θhkl) between the planes and the incoming beam, by the Bragg equation .
Where λ is the wavelength of the X-rays and n is the order of diffraction. For diffraction it is also necessary that θhkl is the angle between the diffracted beam and the planes. Further the incoming and diffracted beams must be in a plane normal to the set of diffracting planes. Once the diffraction angles ‘θ’ are measured, the corresponding d’s and [hkl] values can be fixed. In the geometry of the practical diffractometers, only 2θ can be measured. So from the photographed X-ray pattern, the 2θ values and the intensity of the maxima can be found and a plot between 2θ and intensity made for studies. The modern X-ray diffractometers (XRD) make use of a built in computer, which is programmed to give directly the print out of a plot of 2θ versus intensity of the diffracted beam (Figure 1). The crystallite size was determined by means of the X-ray line broadening method using the Scherer equation.
Where, D, the crystallite size, λ, the wavelength of the radiation (1.5406Å for Cu-Kα radiation), β, the corrected peak width at halfmaximum intensity, and θ, the peak position.
The calculated average crystallite size and its lattice parameters were tabulated in Tables 1 and 2 for the as-prepared sample and Tables 3 and 4 for 200°, for Li2ZnCl4 NPS which reveals the nanocrystalline size of the prepared powder. From this value, the specific surface area was calculated assuming the presence of spherical particles, by means of the equation.
Where, ρ, the calculated density of the material was nearly 2.536 g/cm3 and D, the crystallite size of the sample. It has orthorhombic primitive lattices. From the Tables 1-4 the surface area of the particle 420 diffraction planes are different .
|2Ө (obs)||2Ө(JCPDS) 86-1806||FWHM||dobs||Dexp (JCPDS) 86-1806||hkl||S=6/ρD|
Table 1: Structural properties or the sample 5% concentration of Zn with Lithiumchloride aspreapred powdered particles.
|hkl||Crystal Size (nm)||Lattice parameter (A°)|
Table 2: Crystal size and its lattice parameters for the sample 5% concentration of Zn with Lithium chloride for the as-prepared sample.
|2Ө (obs)||2Ө(JCPDS) 86-1806||FWHM||dobs||dexp (JCPDS) 86-1806|
Table 3: Structural Properties for the sample 5% concentration of Zn with Lithium chloride at 200°C.
|hkl||Crystal Size||Lattice parameter (A°)|
Table 4: Crystal size and lattice parameters values for the sample 5% concentration of Zn with Lithiumchloride at 200°C.
SEM Analysis of Li2ZnCl4
Figures 2a and 2b shows the surface morphology of Li2ZnCl4 powdered particles prepared at proportions of (9:1) at room temperature for 1.0 Molar solution concentrations were observed. From these images it can be seen that the grain sizes of the powdered particles are not uniform. Therefore average grain sizes were estimated from different grains within the powder and to be about 0.8 μm to 1.0 μm. It is also seen that the edge texture of the particles become sharper and the grain boundaries become clearer by increasing the Zn content. It exhibits spherically shaped secondary particles consisting of primary nanospheres of approximately 0.8 μm to 1.0 μm .
The room temperature photo luminescent spectra of as prepared sample Li2ZnCl4 nano particles were studied using UV-excitation (λ=370 nm). The data were recorded in the region of 350-550 nm and spectra were shown in Figure 3. Li2ZnCl4 nano particles in the percentage of 0.05 equally were doped with Zn of 99% were dissolved in ethanol containing a weak UV emission at 493 nm (2.6 eV) and relatively intense emission at 532 nm (2.33 eV). The weak ultra violet emission at 494 nm is attributed to band edge emission which is associated with in the vacancy related to defects emission for 200°C sample. The medium intensity of other two peaks was due to the enhancement of non radioactive recombination process which occurred for the annealing samples .
First time by simple co-precipitaton method Li2ZnCl4 NPs were prepared. The crystallite sizes for ASP and 200°C particles were calculated nearly equal to 47.06 nm and 57.64 nm the lattice parameter and dislocation densities were under the very small regimes. This is due to the small crystal size of the prepared particles. Due to its agglomeration the particle size becomes larger in μm shown in its morphological studies of Scanning Electron Microscopy. The PL analysis emission wavelength in nm well matched with the calculated prepared molar ratio of the source materials.
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Citation: Kathoon Sanofer S, Madhumitha B, Ponsurya P, Abbas Shahul Hameed BH, Mikila Vaahini K, et al. (2018) Lithium Zinc Chloride Nanoparticles by Simple Co-Precipitation Method. J Bioengineer & Biomedical Sci 8: 254. DOI: 10.4172/2155-9538.1000254
Copyright: © 2018 Kathoon Sanofer S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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