Ionic Contributions Research Articles

First principles study of the structural, mechanical and optical properties of argyrodite-structured Ag6PS5X (X= Br, I) compounds

Argyrodite-structured sulphides solid electrolytes, which are currently the most widely utilized solid electrolytes for all-solid-state battery manufacturing have gained reasonable interest recently. Here, the electronic structure, optical and elastic properties of Ag6PS5X (X = Br, I) Silver based Argyrodite have been obtained using density functional theory (DFT). The well-known Perdew-Burke-Ernzerhoff generalized gradient approximation (PBEsol-GGA) was used for calculations of structural and elastic parameters, whereas Tran-Blaha approach of the modified Becke–Johnson (TB-mBJ) potential was used to get more reliable results for the energy band structure of Ag6PS5Br and Ag6PS5I. All these compounds possess cubic structure with lattice constants increasing from 10.71 Å to 10.74 Å for Ag6PS5Br and Ag6PS5I due to increase in atomic number. TB-mBJ functional shows semiconductor nature with direct band gap lying at the gamma symmetry points. The optical conductivity and absorption co-efficient shows their peaks in ultraviolet region by inserting large size anion moving towards a lower energy range. The band gap of these compounds (1.97 eV, 1.88 eV) indicates their potential in single and multi-junction solar cells. The elastic constants clearly show mechanical stability of the compounds. The calculated B/G ratio shows the ductile nature of these compounds while Poisson ratio varies from 0.20 (Br) to 0.26 (I) shows high ionic contribution in intra-atomic bonding.

Impact of M atomic species on physical properties of M2TlC (M = Ti, Zr, Hf): A first principles calculation

We characterize the physical feature of M2TlC (M = Ti, Zr, and Hf) MAX phase ternary carbides applying density functional theory. Along with previously calculated structural, elastic, and electrical properties, Vickers hardness, dynamical stability, and optical feature of the phases are also calculated. The Pugh ratio and Poisson’s ratio show the compounds’ brittleness in conjunction with their potent directional covalent bonds and combination of ionic contributions. The metallic character of the phases is supported by the Fermi level overlap of the conduction band and valence band. The examined materials have moderate hardness, according to the Vickers hardness, with the Hf2TlC combination having the highest value of 2.60 GPa. A number of well-known phenomena are used to compute and thoroughly analyze the optical characteristics. Notably, all investigated compounds show reflectivity above 44% up to 12.0 eV energy, which is encompassed by the infrared and visible regions. The compounds could therefore be used, in practice, as a coating material to lessen solar heating.

Prediction of CO2 and N2 solubility in ionic liquids using a combination of ionic fragments contribution and machine learning methods

Ionic liquids (ILs) with many unique features can act as green solvents to dissolve some gases. In this study, two databases are collected to predict the CO2 and N2 solubility in various kinds of ILs with different temperature and pressure ranges. Firstly, 13,055 CO2 solubility data in 164 kinds of ILs and 415 N2 solubility data in 38 kinds of ILs are established. The hundreds of ILs are divided into dozens of ionic fragments (IFs). Then, the quantitative structure–property relationship (QSPR) model is built by combining ionic fragments contribution (IFC) with support vector machine (SVM) and artificial neural network (ANN) to establish the relationship between gas solubility and ILs structure. As a result, for CO2 solubility prediction, the determination of coefficient (R2) is 0.9855 and 0.9732 for training sets by IFC-SVM and IFC-ANN, respectively, while for N2 solubility prediction, the R2 is 0.9966 and 0.9909 for training sets by IFC-SVM and IFC-ANN, respectively. The result indicates that both IFC-SVM and IFC-ANN models can accurately and reliably predict CO2 and N2 solubility in ILs, so as to guide the screening of ILs.

Cell voltage of mixed conductors under partially frozen conditions

Partially frozen-in states are rather the rule than the exception. Coexistence between equilibrium states and frozen-in states is relevant in view of the diversity and complexity of charge carriers, or sublattices, especially in multinary compounds, but also with respect to differently equilibrated spatial regions. This contribution deals with the open circuit potential of samples where only surface-near regions feel the outer partial pressure, or more generally, the component chemical potentials, established by the electrodes. In view of the significance of such measurements for separating ionic and electronic conductivity contributions, and the kinetic difficulties in getting full equilibration near room-temperature, the value of these considerations is obvious. The necessary relations are derived, or their derivations are sketched within the framework of linear force–flux laws. An account is made of recent emf measurements of hybrid halide perovskites, and a refinement of their standard defect diagram is recommended.

Cation Co-intercalation in Potassium Copper(II) Hexacyanoferrates.

The cation-insertion solid state electrochemistry of a potassium copper(II) hexacyanoferrate in contact with LiClO4 /DMSO, NaPF6 /DMSO, and KPF6 /DMSO electrolytes has been theoretically and experimentally studied using the voltammetry of immobilized particles methodology. Voltammetric data, combined with SEM/EDS analysis permit to determine a K0.876 CuII 1.328 FeIII 0.049 [FeIII 0.318 FeII 0.682 (CN)6 ] stoichiometry for the synthesized solid. Separation of electronic and ionic contributions to Gibbs energy changes can be made based on cyclic voltammetric and open circuit potential measurements. These parameters can be combined to measure values of the Gibbs energy of cation-independent electron transfer of 7.2±0.4 (K+ ), 7.1±0.5 (Na+ ) kJ mol-1 , in close agreement with the expected independence of this parameter on the electrolyte cation. The reduction Fe(III) centers bound to cyano groups exhibit a cation-dependent, essentially Nernstian character which can be described in terms of Na+ and K+ insertion/deinsertion while in the case of Li+ electrolytes there is significant co-cation diffusion. Chronoamperometric data provide estimates of the diffusion coefficients of Na+ , and K+ ions through the solid around 10-9 cm2 s-1 .

Structural, Optical and Ionic Properties of PVA Capped CuS Quantum Dots

Copper sulphide quantum dots were synthesized by a simple chemical route using ammonia (aq.) as a complexing agent in PVA matrix. Copper acetate monohydrate and thiourea were used as precursors. The particle sizes as obtained from XRD results were found to be in good agreement with those of HRTEM. The UV-Vis. absorption and PL emission spectra exhibited a systematic blue shift of absorption and emission respectively confirming quantum confinement effect in the synthesized quantum dots. The band gap as estimated from Tauc-plot increased from 3.26eV to 3.92eV with change of concentration of complexing agent. The FTIR spectra exhibited Cu-S stretching peaks characteristic of CuS. Ionic contributions of the electrolytic ionic CuS solution as measured by a standard conductivity cell clearly showed the semiconducting behavior of the product material. The synthesized material may be exploited in fabrication of an optoelectronic device in UV-blue region.

Addition of V2O5 in lithium aluminium oxy-fluorophosphate glass system: A possible glassy cathode?

Glass formation region in ternary LiF‒Al(PO3)3‒V2O5 system was determined by melt quenching technique. Homogeneous glasses were obtained by varying V2O5 between 2‒70 mol%. 80LiF‒20Al(PO3)3 composition was chosen as parent glass. V2O5 was added until stable glasses could be cast. V2O5 was substituted for LiF and/or Al(PO3)3 to test its role as glass modifier and/or glass former in presence of Al(PO3)3. Glasses were characterized using XRD, DSC, ICP-AES, FTIR and Electrical Impedance Spectroscopy. V2O5 played dual role‒ of network modifier at low concentrations and of network former with its progressive additions, changing glass structure from predominantly phosphate to vanadophosphate network. These structural changes correlated with the measured properties. Electrical conductivity increased substantially upon V2O5 addition and changed from being predominantly ionic to mixed conduction, with comparable ionic and electronic contributions for ≥ 35 mol% of V2O5, making it a possible candidate for glassy cathode.

Near-Field Radiative Heat Transfer between $\\beta-$GeSe monolayers: An ab initio study

ABSTRACT We present a theoretical study of the near-field radiative heat transfer (NFRHT) between two -GeSe monolayers, each at a different temperature. (This is a relevant 2D material with superior electron transport and optical properties compared to black-phosphorus monolayers). The required optical conductivity of the monolayer is calculated using density functional theory including spin-orbit coupling, and using the Perdew-Burke-Erzenhof parametrization. Both the intra and interband transitions are taken into account, as well as the contribution of the optical phonons. This allows us to obtain more realistic predictions of the NFRHT between two monolayers of GeSe. The role of the electron doping concentration and the plasma relaxation frequency is investigated, showing a non-monotonic dependence on the radiative heat transfer with increasing doping, and having an optimal doping where the heat flux is maximize. A strong optical anisotropy in the electric conductivity is obtained from the contribution of both electrons and ions This anisotropy is explored, showing that the relative rotation of two monolayers results in modulation of the NFRHT much larger than previously found for similar 2D materials, like -GeSe. As the angle of rotation between the monolayers increases the total heat transfer decreases. Our analysis demonstrates the relevance of properly taking into account the materialelectronic and ionic contributions.

First-principles theory of electrochemical capacitance

The differential capacitance comprises the most relevant thermodynamic information about an electrochemical system. Classical approaches to describe electrochemical capacitance have difficulties to combine the treatment of the ionic contribution of the electrolyte with the electronic contribution of the electrode. Moreover, different approaches are typically required for the description of the double-layer capacitance, on the one hand, and the pseudocapacitive contribution due to adsorption or intercalation of reactive species, on the other. In the present work, a new approach to describe electrochemical capacitance from first principles is developed. The treatment of a general electrochemical system at the level of multicomponent density-functional theory (MCDFT) yields an exact analytical expression for the total capacitance of the system, which corresponds to a formal series-circuit partitioning into “quantum” capacitance contributions of the density of states of electrons and ions, the (mean-field) electrostatic capacitance, as well as capacitance contributions of exchange and correlation among all active species. It is shown that the classical expression of the double-layer capacitance involving the interfacial Galvani potential is obtained in the limit of extended electrode and electrolyte regions. Importantly, the present formalism also describes systems with confined electrode and electrolyte phases, where the definition of the (classical) inner potentials of the electrode and electrolyte domains becomes problematic. Moreover, the new approach unifies the treatment of double-layer capacitance and pseudocapacitance resulting from reactive processes.

Hydrochemical and isotopic composition of periglacial watersheds in Northern Patagonian Andes

Mountain periglacial environments are important sites of water storage and distribution to downstream areas. The present study was conducted in the “La Hoya” subwatershed, in the Northern Patagonian Andes. La Hoya is the main water recharge area of the “Los Bandidos” watershed, from which fresh water is used for human consumption. The aim of this work was to study the hydrogeochemical and isotopic composition of this watershed and evaluate the hydrological and ionic contributions from periglacial landforms, accounting for annual water flow hydrodynamics and climatic trends. Meteorological data, spring and stream flows, electrical conductivity, isotopic content, and major ion concentrations of snow, spring, and stream samples were analyzed from December 2020 to November 2021. Snow melting is the main water contribution to the mountain watershed. Part of the snowmelt drains superficially during the melting season and part of it infiltrates into periglacial landforms, where it is provisionally stored as groundwater. Chemical weathering during groundwater-rock interaction is the main process that regulates water chemical composition, dominating the dissolution of CO2(g) and carbonates, which controls the waters to be of the Ca–HCO3 to Ca–Mg–HCO3 facies type of groundwater. The climate tendency for the last sixty years in this area reflects a decrease in precipitation and an increase in temperatures. This climate trend could affect periglacial environments, modifying the chemical and physical processes that take place in them, which could affect the chemical water quality and the hydrological behavior of the watershed. The chemical and hydrological behavior in watersheds for human consumption should be specially monitored for better use of this resource.

Pressure-dependent semiconductor–metal transition and elastic, electronic, optical, and thermophysical properties of orthorhombic SnS binary chalcogenide

Pressure dependent physical properties of binary SnS compound have been studied using the density functional theory based methodology. The computed elastic constants reveal that SnS is stable mechanically and is brittle under ambient conditions. With increasing pressure, the compound becomes ductile. The Poisson’s ratio and Cauchy pressure also indicate brittle-ductile transition when pressure increases. The hardness of SnS increases significantly with pressure. The compound possesses elastic anisotropy. The ground state electronic band structure is semiconducting with a small band gap. The band structure becomes metallic under pressure. The bands crossing the Fermi level become more and more dispersive with the increase in pressure while the electronic correlations decrease as pressure is raised. Both the Debye temperature and the phonon thermal conductivity of SnS increase sharply with pressure. The melting temperature of the compound is low. Mixed bonding characteristics are found with ionic and moderate covalent contributions. SnS is a good absorber of ultraviolet light. The reflectivity of the material increases with the increase in the pressure. The reflectivity is nonselective over a wide spectral range. The low energy refractive index is high. The low band gap energy under ambient conditions makes SnS suitable for photovoltaic applications. Non-selective and high reflectivity of SnS indicates that this compound can be used as a coating material to reduce solar heating. Unlike structural anisotropy, the optical anisotropy of SnS is low.

The Unignorable Near-ground PM2.5, UFP, PAHs, and BC Levels around a Traffic Prohibited Night Market

In some special densely populated areas, the background atmospheric fine particulate matter (PM2.5) concentration is very high, which makes near-ground (NG) exposure a major problem endangering human health. In our study, the night market in Chiayi City was selected as the research object and collected the 24-hour PM2.5 samples through the federal reference method (FRM), characterizing the mass concentration, water-soluble ionic components, carbon specious, metal compositions and source contributions of PM2.5. To better analyze the contribution of traffic sources under different sampling conditions, the mobile real-time monitoring system was used to analyze the quality of NG-PM2.5, the number of ultra-fine particles (UFP), the concentration of black carbon (BC) and total polycyclic aromatic hydrocarbons (PAH) before and after the traffic restriction. Results indicated the concentration of PM2.5 was 7.26–58.6 mg m-3. In chemical analysis, secondary contents e.g., carbonaceous and ionic components accounted for ~60% of the PM2.5, supporting the importance of long-range transport. However, the traffic contribution accounted for ~30% and hardly changed between different samples, which was not conducive to source apportionment. Through traffic restriction, it was found that all kinds of pollutants increased significantly before restriction, and even after restriction, the concentrations of PM2.5 and BC increased 131% and 151% in low concentration season. In the high concentration season, the traffic restriction significantly reduced the NG-UFP and NG-PAH concentration by 27% and 55%, respectively, but NG-BC and NG-PM2.5 was almost unaffected. Therefore, besides the contribution of traffic source, emissions from cooking activities are very important for the increase of NG-PM2.5 levels in the night market area.

A new method of Ionic Fragment Contribution-Gradient Boosting Regressor for predicting the infinite dilution activity coefficient of dichloromethane in ionic liquids

Ionic liquids (ILs) have shown huge potential advantages as solvents to absorb and recover dichloromethane (DCM) from waste gases. The infinite dilution activity coefficient ( γ ∞ ) of DCM in ILs is an important parameter, which can be used to predict the vapor-liquid equilibrium of DCM-IL systems. In this work, a new model of calculating the γ ∞ of DCM in ILs is established based on ionic fragments contribution (IFC) and gradient boosting regressor (GBR) algorithm. IFC is used to obtain the surface charge density distribution area of ILs (S σ-profile ) that is the input of GBR. GBR is used to learn the mapping relationship between input feature and γ ∞ of DCM in ILs. The database of the γ ∞ of DCM in ILs composed of 29 cations and 22 anions includes 72 experimental data and 421 COSMO calculation data, which was employed to establish the IFC-GBR model and predict the γ ∞ of DCM in ILs. The coefficient of determination (R 2 ) and mean absolute error (MAE) of the IFC-GBR model test set are 0.9703 and 0.0519, respectively. Also, this model has excellent generalization capability of predicting evidenced by high 10-fold cross-validation coefficients of determination in the range 0.9474–0.9481. These results indicate that the proposed model can accurately predict γ ∞ of DCM in ILs, then provide the important data for developing a new process of absorbing and desorbing DCM by IL-based technologies.

Strain-induced giant enhancement of anisotropic dielectric constant in layered nitrides SrHfN2 and SrZrN2.

The development of information technology puts forward huge demand for electronic materials with high dielectric constants; first-principles calculations and simulations have been demonstrated as an efficient technique for screening and exploring novel dielectric materials. In the present study, first-principles calculations combined with density functional perturbation theory are employed to study the dielectric properties of two newly discovered layered nitrides SrHfN2 and SrZrN2 under strain. By analyzing the evolution of lattice distortion, dielectric constant, Born effective charge, and phonon modes along with the applied strain, we find that the biaxial strain and isotropic strain can effectively modulate the dielectric constant. The two nitrides SrHfN2 and SrZrN2 are dynamically stable up to biaxial tensile strains of 2.1% and 1.8%, and the dielectric constants have been enlarged to about 500 and 2000. Furthermore, the dielectric constant is dramatically enhanced by 15 (9) times to a maximum value of ∼2600 (2700) under an isotropic tensile strain of 1.2% (0.7%) for SrHfN2 (SrZrN2), which is mainly due to the softening of the lowest-frequency infrared-active phonon mode and the increasing octahedral distortion degree. Particularly, the ionic contribution of the dielectric constant shows very remarkable anisotropy and plays a dominant role in the change of the dielectric constant, whose in-plane components exhibit giant enhancement by 18 (10) times for SrHfN2 (SrZrN2). This work not only sheds light on the experimentally observed high dielectric constants of SrHfN2 and SrZrN2, but also provides an effective route to regulate the anisotropic dielectric constants by applied strain, which indicates promising applications in optical and electronic devices.

A study on the electrical and dielectric traits of ternary NiCuZn-spinel ferrites co-substituted with Ga3+-Gd3+ ions

This report focus on the effect of Ga-Gd co-substitution on the structural, conductivity and dielectric properties Ni0.4Cu0.4Zn0.2GaxGdxFe2-2xO4 (x ≤ 0.04) nanospinel ferrites (NCZGaGd NSFs). Some consequential electrical and dielectric parameters of NCZGaGd NSFs have been extensively assessed as functions of bias frequency, measurement temperature, and co-substitution ratios in logarithmic 3D graphs by complex impedance spectroscopy. XRD analyses verified the cubic spinel structures. The morphology and chemical composition of all products have been investigated by TEM and FE-SEM along with EDX. The different substitution ratios of both Ga and Gd ion were used to synthesize NCZGaGd NSFs via sonochemical approach using ultrasonic irradiation. These parameters such as ac/dc conductivity, dielectric constant and loss, dissipation factor and Cole-Cole plot analysis have been extensively evaluated for frequencies up to 3.0 MHz at temperature between 20 °C and 120 °C. It is verified that the ac conductivity obeys the power law frequency rule for each co-substitution ratio, and it is also understood from the reactive changes in the graphs that the dependence of both temperature and co-substitution ratios in ternary NiCuZn NSFs is highly effective in terms of grains and grain boundaries as well as the number of elements in its composition. It was observed how the activation levels and dc conductivity trends from the Arrhenius plot changed with the co-substitution of Ga3+-Gd3+ ions to ternary NiCuZn NSFs; this implies that the conduction mechanism is due to both polaron and electron hopping as well as ionic contribution. All dielectric parameters were noted to undergo moderate frequency-dependent variation at temperatures up to 120 °C for the various Ga3+-Gd3+ ions co-substitution ratios. Nyquist plots of the Cole-Cole impedance functions show a semicircle of various diameters depending on temperature and co-substitution ratio; This indicates that the resistive and capacitive responses of ternary NiCuZn NSFs are due to the contribution of grains and grain boundaries, and ions in the compositional element formed in the structures of the ternary NiCuZn NSFs. Extensive changes in fitting parameters of Nyquist plots of Cole-Cole impedance functions show that there is much contribution on the conduction mechanism due to the complexity of the co-substituted ternary NiCuZn NSFs system.

Operando AC In-Plane Impedance Spectroscopy of Electrodes for Energy Storage Systems

Characterization of battery and supercapacitor materials and devices is typically performed using various methods such as cyclic voltammetry, electrochemical impedance spectroscopy, galvanostatic cycling, etc. However, none of these techniques allow for operando tracking of changes in the electrode material’s in-plane ionic and electronic percolation under polarization, which plays a key-role in the electrochemical performance of the material. Here, we report an experimental set-up devoted to measuring the operando in-plane AC impedance and DC resistance of porous activated carbon and Ti3C2 MXene electrodes during electrochemical cycling. These impedance measurements allow for the deconvolution and tracking of the ionic and electronic contributions of the total impedance and the change in these components under polarization. Operando tracking of the in-plane electrode impedance under polarization brings insights regarding electronic and ionic transport mechanisms of electrodes during operation. This set-up serves as a complementary tool to further evaluate and improve the performance of electrode materials for energy storage.

First-principles investigation on the novel half-Heusler VXTe (X=Cr, Mn, Fe, and Co) alloys for spintronic and thermoelectric applications

Half-Heusler (HH) alloys are a well-known and extensively researched family of thermoelectric (TE), magnetic, and spintronic materials. Doping may significantly increase the thermoelectric conversion efficiency of these materials; nevertheless, practical applications remain far. As a result, the hunt for superior parent TE alloys is critical. Using extensive first-principles density functional calculations, we predicted a novel class of vanadium-based four HH VXTe alloys, where X is one of the four elements: Cr, Mn, Fe, and Co. Their TE properties, as well as their mechanical, magnetic, electrical, and structural stability, have been studied in depth. Their mechanical and thermodynamic stability is confirmed using the predicted elastic constants, formation and cohesive energies, and phonon spectra. A comprehensive analysis of elastic constants and moduli demonstrates that HH VXTe alloys possess elastic anisotropy with reasonably good machinability, higher melting and Debye temperatures, mixed bonding characteristics with ionic and covalent contributions, and brittle nature, except for VCoTe, which is ductile. We find that the ground state of HH VCrTe and VFeTe is ferrimagnetic, while HH VCoTe is ferromagnetic and HH VMnTe is non-magnetic. Three VXTe (X = Cr, Fe, & Co) alloys demonstrated half-metallicity with 100% spin-polarization, whereas HH VMnTe is an 18-electron indirect semiconductor. In the studied HH VXTe alloys, most of the heat flow is caused by the phonon-group velocity of the acoustic phonons. Further studies on the relationship between carrier concentration and temperature dependence of TE properties reveal that the high ZT ∼1.2 at 1000 K of the pristine HH VMnTe alloy is obtained due to its high-power factor of 249.4×1012Wm−1K−2 and this value is greater than the values of some known pristine and doped HH TE materials. Our findings pave the way for further investigation into the HH VXTe alloys in the quest for improved TE and spintronic materials for use in domains that necessitate high thermoelectricity and spintronic performance.

Ab initio nonlinear optics in solids: linear electro-optic effect and electric-field induced second-harmonic generation

Second-harmonic generation (SHG), linear electro-optic effect (LEO) and electric-field induced second-harmonic generation (EFISH) are nonlinear optical processes with important applications in optoelectronics and photovoltaics. SHG and LEO are second-order nonlinear optical processes described by second-order susceptibility. Instead, EFISH is a third-order nonlinear optical process described by third-order susceptibility. LEO and EFISH are only observed in the presence of a static electric field. These nonlinear processes are very sensitive to the symmetry of the systems. In particular, LEO is usually observed through a change in the dielectric properties of the material while EFISH can be used to generate a “second harmonic” response in centrosymmetric material. In this work, we present a first-principle formalism to calculate second- and third-order susceptibility for LEO and EFISH. LEO is studied for GaAs semiconductor and compared with the dielectric properties of this material. We also present how it is possible for LEO to include the ionic contribution to the second-order macroscopic susceptibility. Concerning EFISH we present for the first time the theory we developed in the framework of TDDFT to calculate this nonlinear optical process. Our approach permits to obtain an expression for EFISH which does not contain the mathematical divergences in the frequency-dependent second-order susceptibility that caused until now many difficulties for numerical calculations.

On the Theory of Magnetoelectric Coupling in Fe2Mo3O8.

In the last decade, Fe2Mo3O8 was recognized for a giant magnetoelectric effect, the origin of which is still not clear. In the present paper, we contribute to the microscopic theory of the magnetoelectric coupling in this compound. Using crystal field theory and the molecular field approximation, we calculated the low-lying energy spectrum for iron ions and their interaction with electric and magnetic fields. Classical ionic contribution to the electric polarization related to the ionic shifts is also estimated. It is found that the electronic and ionic contributions to the electric polarization are comparable and these mechanisms support each other at T<TN. The suggested electronic mechanism provides insight into the nature of huge jumps in polarization upon phase transitions from paramagnetic (PM) to antiferromagnetic (AFM) and then to ferrimagnetic (FRM) states under an applied external magnetic field as well as the large differential magnetoelectric coefficient.

Electrical conductivity and relaxation in lithium-doped barium vanadate glasses investigated by impedance spectroscopy

We present herein a detailed study of the electric and dielectric properties of glasses with the composition 60V2O5–(40–x)BaO–xLi2O, where x = 10, 15, 20, or 25 mol%. The conduction and relaxation mechanisms have been studied by impedance spectroscopy over the frequency range from 40 Hz to 10 MHz and at various temperatures. With constant transition metal oxide content, the conductivity variation in the glasses is assumed to be mainly due to an ionic contribution. The dependence of electrical conductivity on frequency has been analysed using Jonscher's power law. Properties of the glasses, such as electric modulus loss and relaxation mechanism, have been analysed in terms of electric modulus using the Kohlrausch–William–Watts (KWW) equation, which describes the relaxation behaviour of the mobile ions as non-Debye in nature. Scaling of ac conductivity and electric modulus data has shown that conductivity relaxation is independent of temperature. The non-monotonic variation in the stretching parameter β has been found to show a positive correlation with various activation energies, namely electrical activation energy, relaxation activation energy, and the activation energy from the Anderson–Stuart model. The anomalous behaviour of activation energy with respect to conductivity has been substantiated through structural insight. The conductivity was found to be highest in glasses with 25 mol% Li2O, while coupling between the mobile ions was best for glasses with 20 mol% Li2O.