Lakshmi Vijayan

Structure and ion transport in Li3Fe2(PO4)3 synthesized by solution combustion technique

Li3Fe2(PO4)3 is interesting because of its technological application and environmentally benign nature. Nanocrystalline Li3Fe2(PO4)3 is synthesized by a solution combustion technique. The role of fuels/complexing agents in deciding the structural parameters and ac electrical behavior is investigated in this study. Antiferromagnetic nature and direct bandgap energy of 3.09 eV are recognized in the material. Enhanced conduction is established through mobility of Li+ ion in four co-ordination in the modified monoclinic symmetry and high temperature stability through orthorhombic symmetry. Quality of electrical data is confirmed through a Kramers-Kronig test and electrical relaxation parameters are obtained from modulus analysis. Scaling analysis of modulus data confirmed the time-temperature superposition principle.

Electrical Conductivity Studies of Solution Combustion Synthesized Nanocrystalline Li2NiZrO4 material

A phase‐pure nanocrystalline Li2NiZrO4 material is synthesized by solution combustion synthesis. In this study citric acid is used as fuel and pH of the homogenous solution is maintained. The material is crystallized in a cubic rock‐salt structure of space group Fm□3m. TEM analysis revealed that the material is formed as nano‐crystallites. The structural characterization is accomplished through X‐ray diffraction, thermo gravimetry/differential thermal analysis, transmission electron microscopy and electrical characterization is done through impedance spectroscopy and the results are reported.

Electrical conductivity studies of graphene wrapped nanocrystalline LiMnPO4 composite

Nanocrystalline LiMnPO4 material was synthesized by template free sucrose assisted hydrothermal method. The material possesses the orthorhombic crystal structure with Pnma, space group having four formula units. The GO was prepared by the hummer’s method and it was reduced graphene oxide (rGO) with hydrazine hydrate in the presence of nitrogen atmosphere. LiMnPO4 material was wrapped by the rGO to increase its conductivity. The structural characterization was accomplished through X-ray diffraction, FT-IR and Raman spectroscopy. Morphology was identified by the SEM, Electrical characterization was done through impedance spectroscopy and the results were reported.

Ion dynamics in nanocrystalline LiMnPO4 synthesised by novel template free hydrothermal approach

A dense core rectangular shaped nanocrystalline LiMnPO4 material was synthesized by template free sucrose assisted hydrothermal synthesis. The material possess orthorhombic crystal structure with Pnma, space group having four formula units. The structural characterization was accomplished through X-ray diffraction, thermo gravimetry/differential thermal analysis. Morphology was identified by the SEM, VSM was used to verify the magnetic behavior of the material and electrical characterization was done through impedance spectroscopy and the results were reported.

Structural and ac electrical properties of LiCoPO4 synthesised by template free hydrothermal approach

Olivine structured material shows specific capacities up to 170mAh/g and can be charged in a very short time. LiMPO4, (M=transition metal ion) does not consists of heavy metal and have no memory loss like Ni-Cd, Ni-metal hydride solutions. Benefit of LiMPO4 is its flexibility for the cell design and battery applications. Li based LiCoPO4 of Orthophosphate family is synthesized by template free sucrose assisted hydrothermal method. Olivine structured compounds possess orthorhombic crystal structure with Pnma, pmnb space group having four formula units. The material is characterized through different techniques like XRD, FTIR, SEM, VSM and electrical characterization is done through impedance spectroscopy and the results are reported.Olivine structured material shows specific capacities up to 170mAh/g and can be charged in a very short time. LiMPO4, (M=transition metal ion) does not consists of heavy metal and have no memory loss like Ni-Cd, Ni-metal hydride solutions. Benefit of LiMPO4 is its flexibility for the cell design and battery applications. Li based LiCoPO4 of Orthophosphate family is synthesized by template free sucrose assisted hydrothermal method. Olivine structured compounds possess orthorhombic crystal structure with Pnma, pmnb space group having four formula units. The material is characterized through different techniques like XRD, FTIR, SEM, VSM and electrical characterization is done through impedance spectroscopy and the results are reported.

Electrical and magnetic properties of sol-gel synthesized nanocrystalline Li2Ni1−xMgxTiO4 materials

A phase pure nanocrystalline Li2Ni1−xMgxTiO4 cation disordered rock salt phase materials are synthesized by sol-gel technique. The structural characterization is accomplished through XRD, TG/DTA and SEM. The electrical property of the material is investigated through impedance spectroscopy. The magnetic property of the samples is studied through the vibration sample magneto meter (VSM). The VSM data at room temperature shows the lack of ferromagnetic interaction indicates the absence of different valence states. The proximity between activation energies of dc conduction and conduction relaxation indicate that while conducting and relaxing ion has to overcome the same energy-barrier.

Ac conductivity studies of solution combustion synthesized nanocrystalline Li2MgZrO4 material

A phase-pure nanocrystalline Li2MgZrO4 material is synthesized by solution combustion synthesis. In this study citric acid is used as fuel and pH of the homogenous solution is maintained. The material is crystallized in a cubic rock-salt structure of space group Fm⃞3m. TEM analysis revealed that the material is formed as nano-crystallites. The structural characterization is accomplished through X-ray diffraction, thermogravimetry, differential thermal analysis, transmission electron microscopy and electrical characterization is done through impedance spectroscopy and the results are reported.