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First principle calculations based on density functional theory have been performed to investigate the structural stability, electronic structure and Li+ intercalation potential for the compounds LiM2Sn (M= Cd,Zn,Pd). These electrode materials exhibit small percentage of volume change which accounts for excellent structural stability. The computed band structure along high symmetry lines in the Brillion zone, total and partial density of states clearly reveals that insertion of lithium to these electrode materials does not affect their metallic nature. The valence charge density calculation reveals the dominant ionic character of these compounds enables Li+ accommodation.

First-principle calculations based on density functional theory have been performed to investigate the negative electrode behaviors, structural changes, and electronic and bonding properties of lithium intercalated antimonides Ag3Sb and Mg3Sb2. Initial intercalation of lithium to orthorhombic Ag3Sb led to form cubic Li2AgSb. Lithium insertion to hexagonal Mg3Sb2 results in cubic LiMgSb. Further insertion of lithium with the intercalated compounds Li2AgSb and LiMgSb results in to the formation of alkali antimonide Li3Sb. The structural transformation of both antimonides Ag3Sb and Mg3Sb2 followed by the insertion of Li+ ends with the formation of Li3Sb with cubic phase. The computed band structures along high symmetry directions of the Brillouin zone, and total and partial density of states clearly illustrate that the intercalation of lithium with Ag3Sb and Mg3Sb2 changes their metallic nature into semiconductor. From the charge density calculations, it is observed that the covalent bond nature in the parent phases Ag3Sb and Mg3Sb2 changed into ionic bond in the Li+ intercalated phases Li2AgSb, LiMgSb, and Li3Sb.

First principle calculations based on density functional theory have been performed on lithium containing transition metal sulfides Li2TiS3 and Li3NbS4 which are recently identified as novel positive electrode materials for rechargeable Li+ batteries. The calculations were performed to investigate the structural stability, electronic and transport properties of Li2TiS3 and Li3NbS4 along with their corresponding delithiated phases LiTiS3 and Li2NbS4. In this study it has been observed that these lithium containing sulfur materials maintain their face-centered cubic structure upon extraction of Li+. To calculate the structural stability and volume change due to lithium extraction, the total energies of Li2TiS3, Li3NbS4 and their corresponding delithiated phases LiTiS3 and Li2NbS4 have been computed by applying full potential linearized augmented plane wave (FP-LAPW) method implemented in WIEN2K. The equilibrium structural parameters for all the phases were determined by achieving total energy convergence. These electrode materials exhibit very small percentage of volume change with change in Li+ concentration which accounts for excellent structural stability. The computed band structure along high symmetry lines in the Brillouin zone, total and partial density of states clearly reveals that the extraction lithium from these electrode materials does not change their metallic nature. The electronic conductivities of both lithiated and delithiated phases have been calculated by employing BoltzTrap which can be interfaced with WIEN2K. The topological distributions of electron charge density at various critical points within the system were analyzed with the use of CRITIC code which is based on Bader’s theory of atoms in molecules (AIM). From the charge density calculations, it was observed that, there is strong ionic bond and weak covalent bond between atoms of the compounds Li2TiS3 and Li3NbS4. But the ionic bond nature was found to decrease in the delithiated phases LiTiS3 and Li2NbS4. The calculated values of electronic conductivities and discharge voltages for both electrodes are found to be in accordance with the recent experimental reports.

The structural phase transformations of ZnS, ZnSe and ZnTe under high pressure are studied by tight binding linear muffin tin orbital (TB-LMTO) method. A simple cubic 16 (SC16) phase is observed in all three zinc chalcogenides ZnX (X=S, Se, Te) and the stability of the high pressure phases is also presented. In ZnS and ZnSe, the sequence of transformation is similar to zincblende (ZB)→SC16→rock salt (RS), but in ZnTe the transformation sequence is different, namely the SC16 phase is observed above the cinnabar phase. The ground state properties of the phases of zinc chalcogenides ZnX (X=S, Se, Te) are also calculated.

The Electronic properties of chalcopyrite AgMX2 (M=Al, Ga, In; X=S, Se, Te) compounds are studied theoretically by means of full potential Linear Muffin Tin Orbital Method. The equilibrium volume, bulk modulus and indirect energy band gap for the compounds are calculated and compared with the available data and found to be in good agreement. The structural as well as optical properties like dielectric functions, degree of anisotropy and refractive index are also calculated.

Lithium garnet Li7La3Zr2O12 (LLZ) sintered at 1230 °C has received considerable importance in recent times as result of its high total (bulk + grain boundary) ionic conductivity of 5 × 10−4 S cm−1 at room temperature. In this work we report Li+ transport process of Li7−2xLa3Zr2−xWxO12 (x = 0.3, 0.5) cubic lithium garnets. Among the investigated compounds, Li6.4La3Zr1.7W0.3O12 sintered relatively at lower temperature 1100 °C exhibits highest room temperature (30 °C) total (bulk + grain boundary) ionic conductivity of 7.89 × 10−4 S cm−1. The temperature dependencies of the bulk conductivity and relaxation frequency in the bulk are governed by the same activation energy. Scaling the conductivity spectra for both Li6.4La3Zr1.7W0.3O12 and Li6La3Zr1.5W0.5O12 sample at different temperatures merges on a single curve, which implies that the relaxation dynamics of charge carriers is independent of temperature. The shape of the imaginary part of the modulus spectra suggests that the relaxation processes are non-Debye in nature. The present studies supports the prediction of optimum Li+ concentration required for the highest room temperature Li+ conductivity in LixLa3M2O12 is around x = 6.4 ± 0.1.

We report a theoretical calculation of the band structure, electrical resistivity, and superconductivity of fcc thorium under pressure. The effect of pressure on the band structure is obtained by means of the linear muffin‐tin orbital (LMTO) method. The superconducting transition temperature (Tc) is calculated using McMillan’s as well as Allen‐Dynes modified formulas. The calculated values of Tc initially decreases with the increase in pressure up to 154 kbar and then begins to increase. The sudden increase in the value of Tc around 181 kbar is attributed to the change in Fermi surface topology. The theoretically calculated values of resistivity initially decreases with increase in pressure up to 154 kbar and then begins to increase in accordance with the experimental results.

The superconducting transition temperture and the electrical resistivity of Te in the bcc phase has been studied. The necessary parameters required to calculate Tc and Egp are taken from the band structure output of Linear muffin‐tin orbital method within the atomic sphere approximation. The superconducting transition temperature (Tc) is calculated using the McMillan’s formula. The calculated value of Tc of Te in the bcc phase at 27.3 GPa is 7.16 K. Further increase in pressure decreases the Tc values. The calculated value of resistivity at 27.3 GPa is 4.37 μΩcm and further increase in pressure decreases the resistivity, which is a typical behaviour of number of elemental metals under pressure.

Here we report the theoretical calculations of band structure and superconductivity of WC in the NaCl-type structure. The effect of pressure on the band structure is obtained using the linear muffin-tin orbital method. The superconducting transition temperature is calculated using McMillan's formula. The value ofTcat ambient conditions is 5.98 K which increases on compression. The increase inTcvalues with pressure may be due to continuous transfer of s electrons from the carbon site to d states of the tungsten site. The calculated value ofTcat ambient pressure and the positive pressure coefficient ofTcare in agreement with other transition metal carbides and nitrides.