Lithium Mobility Research Articles

Ionic mobility in LixK1 − xSn2F5 (x = 0–0.15) solid solutions obtained by mechanochemical synthesis

The solid solutions LixK1 − xSn2F5 (x = 0–0.15) were synthesized by the mechanochemical method. According to XRD and 19F MAS NMR data, the samples are isostructural to KSn2F5, which has superionic properties. The fluoride-ion jump frequency at a given temperature depends on the LiF concentration and is highest for x = 0.02. The amount of the mobile lithium ions at 420 K is maximal for Li0.075K0.925Sn2F5. Two types of fluorine positions with different jump frequencies are present in the structure of the compounds. Occupancy factors of the positions depend on the dopant concentration.

Structure of [60]fullerene with a mobile lithium cation inside.

The structure of crystalline [60]fullerene with a lithium cation inside (Li+@C60) was determined by synchrotron radiation X-ray diffraction measurements to understand the electrostatic and thermal properties of the encapsulated Li+ cation. Although the C60 cages show severe orientation disorder in [Li+@C60](TFPB−)·C4H10O and [Li+@C60](TFSI−)·CH2Cl2, the Li+ cations are rather ordered at specific positions by electrostatic interactions with coordinated anions outside the C60 cage. The Li+@C60 molecules in [Li+@C60](ClO4−) with a rock-salt-type cubic structure are fully disordered with almost uniform spherical shell charge densities even at 100 K by octahedral coordination of ClO4− tetrahedra and show no orientation ordering, unlike [Li+@C60](PF6−) and pristine C60. Single-bonded (Li+@C60−)2 dimers in [Li+@C60−](NiOEP)⋅CH2Cl2 are thermally stable even at 400 K and form Li+–C bonds which are shorter than Li+–C bonds in [Li+@C60](PF6−) and suppress the rotational motion of the Li+ cations.

Defects, Dopants and Lithium Mobility in Li9V3(P2O7)3(PO4)2

Layered Li9V3(P2O7)3(PO4)2 has attracted considerable interest as a novel cathode material for potential use in rechargeable lithium batteries. The defect chemistry, doping behavior and lithium diffusion paths in Li9V3(P2O7)3(PO4)2 are investigated using atomistic scale simulations. Here we show that the activation energy for Li migration via the vacancy mechanism is 0.72 eV along the c-axis. Additionally, the most favourable intrinsic defect type is Li Frenkel (0.44 eV/defect) ensuring the formation of Li vacancies that are required for Li diffusion via the vacancy mechanism. The only other intrinsic defect mechanism that is close in energy is the formation of anti-site defect, in which Li and V ions exchange their positions (1.02 eV/defect) and this can play a role at higher temperatures. Considering the solution of tetravalent dopants it is calculated that they require considerable solution energies, however, the solution of GeO2 will reduce the activation energy of migration to 0.66 eV.

Polaron-Mediated Luminescence in Lithium Niobate and Lithium Tantalate and Its Domain Contrast

In this review article, we discuss photoluminescence phenomena mediated by polarons in lithium niobate (LNO). At first we present the fundamentals on polaron states in LNO and their energy levels, i.e., on free and bound electron polarons, on hole polarons as well as on bipolarons. We discuss the absorption measurements on reduced as well as on doped LNO that made the characterization of the formed polaron states possible by their absorption bands. Next, we proceed by reporting on the two polaron-mediated photoluminescence bands that have been observed in LNO: (1) A near-infrared luminescence band in the range of 1.5 eV shows a mono-exponential decay and a strong dependence on iron doping. This luminescence is emitted by bound polarons returning from an excited state to the ground state. (2) A luminescence band at visible wavelengths with a maximum at 2.6 eV shows a stretched-exponential decay and is strongly enhanced by optical damage resistant doping around the doping threshold. This luminescence stems from the recombination of free electron and hole polarons. The next major topic of this review are domain contrasts of the visible photoluminescence that have been observed after electrical poling of the substrate, as singly inverted domains show a slightly reduced and faster decaying luminescence. Subsequent annealing results in an exponential decrease of that domain contrast. We show that this contrast decay is strongly related to the mobility of lithium ions, thus confirming the role of polar defect complexes, including lithium vacancies, for these domain contrasts. Finally we discuss the extension of our investigations to lithium tantalate (LTO) samples. While the results on the domain contrast and its decay are similar to LNO, there are remarkable differences in their luminescence spectra.

Lithium-Ion Conductivity of Polymers Based on Sulfonated Polystyrene and Polymethylpentene Intercalated by Organic Solvents

Ion-exchange membranes based on polymethylpentene and sulfonated polystyrene with different grafting degrees were obtained. Solvation and mobility of lithium ions depending on the composition of initial organic solvents were studied. The highest ionic conductivity at room temperature (30°C) are obtained for the membranes containing dimethylsulfoxide (σ = 1.31 × 10–4 S/cm for membrane with GD = 78%). Membranes containing dimethylformamide are characterized by a constant phase composition in a broad temperature range and the highest ionic conductivity at low temperature (σ = 9 × 10–6 S/cm at–20°C for a polymer with GD = 78%).

Engineering Surface-Binder Interactions in High Energy Density Nanowire Conversion Electrodes for Improved Cycle Life without Fluorinated Additives

High capacity conversion electrode materials – like silicon and germanium – that undergo a large volume change upon lithiation and delithiation, require the formation of a robust solid-electrolyte interphase (SEI) layer, which is critically important to mitigate deleterious irreversible reactions that occur at the electrode-electrolyte interface. Over time, these irreversible reactions at the electrode surface result in capacity fade by decreasing the number of mobile lithium ions within the cell and by creating a more hindered diffusion path for lithium ions as they travel toward the electrode. To combat the recurrence of these irreversible reactions in high-capacity conversion electrode systems, the addition of electrolyte additives, such as fluoroethylene carbonate (FEC), is typically deemed necessary to promote stable cycling and improve capacity retention. The observed improvements associated with the inclusion of these virtually universally employed additives have been previously attributed to fluorinated reductive decomposition products that enable the formation of a robust SEI layer. Clearly, careful control over interfacial chemistry and surface reactions are critical for the design of robust electrochemical systems; however, the surface chemistry of the active material is typically ignored prior to electrode formulation. In most studies of high capacity conversion electrode materials, the surfaces remained unmodified, and the active material is incorporated irrespective of what uncontrolled – potentially oxidized – surfaces happen to be present in the native state. Herein, we systematically investigate the electrochemical cycling of germanium nanowire composite conversion electrodes with controlled surface chemistry, formulated with an array of polymeric binders, both in the presence and in the absence of fluorinated electrolyte additives. We observe that controlled modification of the nanowire electrode surface, when paired with certain binders, dramatically improved germanium nanowire-based electrode cycling retention and longevity. In fact, some of these pairings exhibit improved capacity retention in the absence of the fluorinated additives typically deemed necessary for stable cycling, whereas the addition of the fluorinated additive caused the cell capacity to fade more rapidly. Finally, through careful control of surface chemistry and strategic choice of binder material, we show that germanium nanowire-based conversion electrodes can maintain capacity retention in the complete absence of fluorinated additives, fluorinated electrolytes, and fluorinated binders.

A first-principle investigation of the Li diffusion mechanism in the super-ionic conductor lithium orthothioborate Li3BS3 structure

The research of superior ionic conductors is a very active field. Identifying such materials would allow for the design of improved solid-state Li-ion batteries, solving the safety hazard posed by the liquid electrolytes and improving the electrochemical stability and thus the energy efficiency. In this work, we study lithium orthothioborate Li3BS3 by means of first-principle atomistic calculations based on density functional theory. This material is a very promising super ion conductor candidate, as it is a layered compound based on a deformed body-centred structure of the anion sublattice. The minimum energy paths for the diffusion of the lithium ions are identified, and the activation energy are evaluated using the nudged elastic band method. A very fast 1D diffusive channel is found, contained in a Li-rich layer, with an activation energy below 0.1 eV. The other paths connecting these layers and extending the mobility of lithium to the whole structure are found to have activation barriers of 0.25 eV or lower. This bottleneck corresponds to a diffusion coefficient of the order of 10-6 cm2 s−1, thus characterising lithium orthothioborate as an excellent ionic conductor.

Characterization of Lithium Ion-Conducting Blend Biopolymer Electrolyte Based on CH–MC Doped with LiBF4

Lithium ion-conducting polymer blend electrolytes based on chitosan and methylcellulose complexed with lithium tetrafluoroborate (LiBF4) were prepared by a solution-casting method. The features of complexation of the solid polymer electrolytes were studied using X-ray diffraction techniques. Electrical conductivity of the prepared films was measured as a function of frequency at a different temperature. The increased trend of the electrical conductivity with increasing temperature and salt concentration can be attributed to increasing the mobility and number of lithium ions, respectively. The polymer electrolyte system exhibited Arrhenius-type, temperature-dependence ion conductivity behavior. Optical properties such as optical band gap, tail due to localized states and complex refractive index were estimated for present polymer electrolyte system from optical absorption measurement in the wavelength region 190–1100 nm. It was found that the optical direct band gap values shifted to lower energies upon addition of LiBF4 salt up to 40 wt% dopant concentration, and showed an increasing tendency for a further increase in dopant concentration. The high refractive index for this composition (2.44–2.63) at visible wavelengths eminently suitable for optical applications.

Insight into lithium-ion mobility in Li2La(TaTi)O7

Using experimental and computational methods, lithium ion mobility and the pathways for lithium conduction in Li2La(TaTi)O7 have been studied.

Revealing the Solvation Structure and Dynamics of Carbonate Electrolytes in Lithium-Ion Batteries by Two-Dimensional Infrared Spectrum Modeling.

Carbonate electrolytes in lithium-ion batteries play a crucial role in conducting lithium ions between two electrodes. Mixed solvent electrolytes consisting of linear and cyclic carbonates are commonly used in commercial lithium-ion batteries. To understand how the linear and cyclic carbonates introduce different solvation structures and dynamics, we performed molecular dynamics simulations of two representative electrolyte systems containing either linear or cyclic carbonate solvents. We then modeled their two-dimensional infrared (2DIR) spectra of the carbonyl stretching mode of these carbonate molecules. We found that the chemical exchange process involving formation and dissociation of lithium-ion/carbonate complexes is responsible for the growth of 2DIR cross peaks with increasing waiting time. In addition, we also found that cyclic carbonates introduce faster dynamics of dissociation and formation of lithium-ion/carbonate complexes than linear carbonates. These findings provide new insights into understanding the lithium-ion mobility and its interplay with solvation structure and ultrafast dynamics in carbonate electrolytes used in lithium-ion batteries.

Solid‐state single‐ion conducting comb‐like siloxane copolymer electrolyte with improved conductivity and electrochemical window for lithium batteries

ABSTRACTAchievement of high conductivity and electrochemical window at ambient temperature for an all‐solid polymer electrolyte used in lithium ion batteries is a challenge. Here, we report the synthesis and characterization of a novel solid‐state single‐ion electrolytes based on comb‐like siloxane copolymer with pendant lithium 4‐styrenesulfonyl (perfluorobutylsulfonyl) imide and poly(ethylene glycol). The highly delocalized anionic charges of SO2N(–)C4F9 have a weak association with lithium ions, resulting in the increase of mobile lithium ions number. The designed polymer electrolytes possess ultra‐low glass transition temperature in the range from −73 to −54 °C due to the special flexible polysiloxane. Promising electrochemical properties have been obtained, including a remarkably high conductivity of 3.7 × 10−5 S/cm and electrochemical window of 5.2 V (vs. Li+/Li) at room temperature. A high lithium ion transference number of 0.80, and good compatibility with anode were also observed. These prominent characteristics endow the polymer electrolyte a potential for the application in high safety lithium ion batteries. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45848.

Lithium isotope fractionation by diffusion in minerals Part 2: Olivine

Recent experiments have shown that lithium isotopes can be significantly fractionated by diffusion in silicate liquids and in augite. Here we report new laboratory experiments that document similarly large lithium isotopic fractionation by diffusion in olivine. Two types of experiments were used. A powder-source method where lithium from finely ground spodumene (LiAlSi2O6) diffused into oriented San Carlos olivine, and piston cylinder annealing experiments where Kunlun clinopyroxene (∼30ppm lithium) and oriented San Carlos olivine (∼2ppm lithium) were juxtaposed. The lithium concentration along traverses across the run products was measured using both laser ablation asa source for a Varian 820-MS quadrupole mass spectrometer and a CAMECA 1270 secondary ion mass spectrometer. The CAMECA 1270 was also used to measure the lithium isotopic fractionation across olivine grains recovered from the experiments. The lithium isotopes were found to be fractionationed by many tens of permil in the diffusion boundary layer at the grain edges asa result of 6Li diffusing significantly faster than 7Li. The lithium concentration and isotopic fractionation data across the olivine recovered from the different experiments were modeled using calculations in which lithium was assumed to be of two distinct types – one being fast diffusing interstitial lithium, the other much less mobile lithium on a metal site. The two-site diffusion model involves a large number of independent parameters and we found that different choices of the parameters can produce very comparable fits to the lithium concentration profiles and associated isotopic fractionation. Because of this nonuniqueness we are able to determine only a range for the relative diffusivity of 6Li compared to 7Li. When the mass dependence of lithium diffusion is parameterized as D6Li/D7Li=(7/6)β, the isotope fractionation for diffusion along the a and c crystallographic direction of olivine can be fit by β=0.4±0.1 while the fractionation in the b direction appears to be somewhat lower. Model calculations were also used to fit the lithium concentration and isotopic fractionation across a natural olivine grain from a peridotite xenolith from the Eastern North China Craton. The isotopic data were fit using β values (0.3–0.36) similar to that of the laboratory experiments. This, along with the fact that the isotopic fractionation is restricted to that part of the mineral with a gradient in lithium concentration, is strong evidence that the lithium zoning of this mineral grain is the result of lithium loss by diffusion and thus that it can be used, as illustrated, to constrain the cooling history.

Relation of short-range and long-range lithium ion dynamics in glass-ceramics: Insights fromLi7NMR field-cycling and field-gradient studies

We use various $^{7}\mathrm{Li}$ NMR methods to investigate lithium ion dynamics in ${70\mathrm{Li}}_{2}{\mathrm{S}\ensuremath{-}30\mathrm{P}}_{2}{\mathrm{S}}_{5}$ glass and glass-ceramic obtained from this glass after heat treatment. We employ $^{7}\mathrm{Li}$ spin-lattice relaxometry, including field-cycling measurements, and line-shape analysis to investigate short-range ion jumps as well as $^{7}\mathrm{Li}$ field-gradient approaches to characterize long-range ion diffusion. The results show that ceramization substantially enhances the lithium ion mobility on all length scales. For the ${70\mathrm{Li}}_{2}{\mathrm{S}\ensuremath{-}30\mathrm{P}}_{2}{\mathrm{S}}_{5}$ glass-ceramic, no evidence is found that bimodal dynamics result from different ion mobilities in glassy and crystalline regions of this sample. Rather, $^{7}\mathrm{Li}$ field-cycling relaxometry shows that dynamic susceptibilities in broad frequency and temperature ranges can be described by thermally activated jumps governed by a Gaussian distribution of activation energies $g({E}_{\mathrm{a}})$ with temperature-independent mean value ${E}_{\mathrm{m}}=0.43\phantom{\rule{0.28em}{0ex}}\mathrm{eV}$ and standard deviation $\ensuremath{\sigma}=0.07\phantom{\rule{0.28em}{0ex}}\mathrm{eV}$. Moreover, use of this distribution allows us to rationalize $^{7}\mathrm{Li}$ line-shape results for the local ion jumps. In addition, this information about short-range ion dynamics further explains $^{7}\mathrm{Li}$ field-gradient results for long-range ion diffusion. In particular, we quantitatively show that, consistent with our experimental results, the temperature dependence of the self-diffusion coefficient $D$ is not described by the mean activation energy ${E}_{\mathrm{m}}$ of the local ion jumps, but by a significantly smaller apparent value whenever the distribution of correlation times $G(log\ensuremath{\tau})$ of the jump motion derives from an invariant distribution of activation energies and, hence, continuously broadens upon cooling. This effect occurs because the harmonic mean, which determines the results of diffusivity or also conductivity studies, continuously separates from the peak position of $G(log\ensuremath{\tau})$ when the width of this distribution increases.

Atomistic Simulations of Lithium Ion Mobility in Battery Electrolytes

Li-ion battery electrolytes are complex solutions composed of solvents, functional additives, and lithium salts. Lithium ion mobility is a central property affecting battery performance. The chemical and physical factors impacting charge transport in complex solutions are not fully understood. Molecular dynamics (MD) simulation is a powerful technique that can provide insight into the critical details impacting ion transport in complex electrolyte solutions. Although several studies have been reported in the literature examining lithium diffusion using MD, limited computational power has restricted simulation time scales to only tens of nanoseconds. Additionally, the simulation results have been hampered due to lack of accurate force-field parameters. In this work, the enhanced predictive reliability for battery electrolytes provided by GPU-accelerated MD using the highly efficient Desmond MD engine [1], along with the quantitative OPLS3 force-field [2] is demonstrated. Using GPU-Desmond/OPLS3, hundreds of simulations can be performed in a production environment with simulation duration in excess of 1 µs. We discuss the impact that simulation duration and force-field has on the accuracy of Li-ion electrolyte simulations. [1] K.J. Bowers, E. Chow, H. Xu, R.O. Dror, M.P. Eastwood, B.A. Gregersen, J.L. Klepeis, I. Kolossvary, M.A. Moraes, F.D. Sacerdoti, J.K.Salmon, Y. Shan and D.E. Shaw, Proceedings of ACM/IEEE Conference on Supercomputing (SC06), Tampa, Florida November 11-17, 2006. [2] E. Harder, W. Damm, J. Maple, C. Wu, M. Reboul, J.Y. Xiang, L. Wang, D. Lupyan, M.K. Dahlgren, J.L. Knight, J.W. Kaus, D.S. Cerutti, G. Krilov, W.L. Jorgensen, R. Abel, R.A. Friesner, J. Chem. Theory Comput., 2016, 12 (1), pp 281; DOI: 10.1021/acs.jctc.5b00864

Study on xLiBH4-NaBH4 (x = 1.6, 2.3, and 4) composites with enhanced lithium ionic conductivity

In the present work, ball-milled xLiBH4-NaBH4 (x = 1.6, 2.3, 4) composites were investigated as fast ionic conductors. It was found that the conductivity σ of xLiBH4-NaBH4 (x = 1.6, 2.3, 4) composites could attain 10−2 S cm−1 when temperature is higher than 373 K. Meanwhile, these σ values are one or two orders of magnitude higher than that of pristine LiBH4 at temperatures below 373 K. A window voltage of 4.5 V was identified by means of the cyclic voltammetry (CV) measurements on xLiBH4-NaBH4 (x = 1.6, 2.3, 4) composites for 5 cycles. The structural stability of xLiBH4-NaBH4 (x = 1.6, 2.3, 4) composites before and after CV tests were demonstrated by X-ray diffraction (XRD) and Fourier Transform infrared spectroscopy (FTIR). They are also very stable during the ramping from room temperature to 393 K. Measurements by differential scanning calorimetry (DSC) observed that both transition enthalpies and transition temperatures were all reduced, implying that the high temperature phase of LiBH4 was stabilized. Such phenomenon facilitates the enhancement of lithium mobility in these composites.

Synthesis and electrochemical properties of cation-disordered Li-Ni-Ti-O compounds as cathode material for lithium ion batteries

Li-excess disordered rock-salt cathode material, Li1+z/3Ni1/2-z/2Ti1/2+z/6O2 (Z = 0, 0.1, 0.2, 0.3, 0.4, 0.5) compounds have been synthesized via a facile sol-gel method. The X-ray diffraction (XRD) indicates that the obtained phase of the Li-excess materials is rock-salt. Morphology and microstructure observation shows that the particles size of this material is well distributed within the range of 100 nm. Cells are examined at room temperature with the voltage range of 2.5–4.5 V and the sample Li1.1Ni0.35Ti0.55O2 delivers the highest capacity of about 116.5 mAh g−1 at 20 mA g−1. The exploration of the lithium mobility in this system indicates that 0-transition metal diffusion channels do form when increasing the amount of Li. Furthermore, combining XRD after cycle, their structure evolution in these cation-disordered Li-excess materials was investigated.

Origin of Structural Evolution in Capacity Degradation for Overcharged NMC622 via Operando Coupled Investigation

The nickel-rich layered oxide materials have been selected as promising cathode materials for the next generation lithium ion batteries because of their large capacity and comparably high operating voltage. However, at high voltage (beyond 4.30 V vs Li/Li+), the members of this family are all suffering from a rapid capacity decay, which was commonly concerned with crystal lattice distortion and related cation disordering. In this work, the quasi-spherical Ni-rich layered LiNi0.6Co0.2Mn0.2O2 (QS-NMC622) material was successfully synthesized through the carbonate co-precipitation method. A coupled measurement, which is a combination of potentiostatic intermittent titration technique (PITT) and in situ X-ray diffraction (XRD), was deployed to simultaneously capture the structural changes and lithium ion diffusion coefficient of QS-NMC622 material during the first cycle. With help of in situ XRD patterns and high-resolution transmission electron microscope (HR-TEM) images, a defective spinel framework of Fd3̅m space group was detected along with a rapid decreasing lattice-parameter c and lattice distortion at deep delithiated state, which causes poor kinetics related to lithium ion mobility. The new-born framework seems to transform and remain as full spinel structure in the parent phase to the end of charge/discharge with high voltage, which could deteriorate both the surface and body structure stability during the subsequent cycles. This established coupled in situ measurement could be applied to simultaneously investigate the structure transformation and kinetics of cathode materials during charge/discharge.

Robust Strategy for Crafting Li5Cr7Ti6O25@CeO2 Composites as High-Performance Anode Material for Lithium-Ion Battery

A facile strategy was developed to prepare Li5Cr7Ti6O25@CeO2 composites as a high-performance anode material. X-ray diffraction (XRD) and Rietveld refinement results show that the CeO2 coating does not alter the structure of Li5Cr7Ti6O25 but increases the lattice parameter. Scanning electron microscopy (SEM) indicates that all samples have similar morphologies with a homogeneous particle distribution in the range of 100-500 nm. Energy-dispersive spectroscopy (EDS) mapping and high-resolution transmission electron microscopy (HRTEM) prove that CeO2 layer successfully formed a coating layer on a surface of Li5Cr7Ti6O25 particles and supplied a good conductive connection between the Li5Cr7Ti6O25 particles. The electrochemical characterization reveals that Li5Cr7Ti6O25@CeO2 (3 wt %) electrode shows the highest reversibility of the insertion and deinsertion behavior of Li ion, the smallest electrochemical polarization, the best lithium-ion mobility among all electrodes, and a better electrochemical activity than the pristine one. Therefore, Li5Cr7Ti6O25@CeO2 (3 wt %) electrode indicates the highest delithiation and lithiation capacities at each rate. At 5 C charge-discharge rate, the pristine Li5Cr7Ti6O25 only delivers an initial delithiation capacity of ∼94.7 mAh g-1, and the delithiation capacity merely achieves 87.4 mAh g-1 even after 100 cycles. However, Li5Cr7Ti6O25@CeO2 (3 wt %) delivers an initial delithiation capacity of 107.5 mAh·g-1, and the delithiation capacity also reaches 100.5 mAh g-1 even after 100 cycles. The cerium dioxide modification is a direct and efficient approach to improve the delithiation and lithiation capacities and cycle property of Li5Cr7Ti6O25 at large current densities.

Lithium barrier materials for on-chip Si-based microbatteries

The integration of lithium-ion batteries, featuring ultra-high discharge rates, directly into silicon-based semiconductor devices opens unique paths towards the development of new mobile micro-electronics applications. Nevertheless, the small and mobile lithium ions have to be confined within the battery area of the silicon chip, otherwise the nearby fine microelectronics devices will be irreversibly damaged. Hence, a barrier material that blocks Li+ transport from the active components of the battery into the surrounding crystalline Si is needed. Here we evaluated the capability of magnetron sputtered barrier films of nitrides and alloys of refractory metals to prevent lithium ion diffusion and, thus, the formation of Li–Si phases outside the battery area. In order to determine the Li profiles in the barrier layer and in the silicon substrate, time-of-flight secondary ion mass spectroscopy was applied for profiling the first microns. In combination with electrochemical testing it turned out that titanium nitride as well as tantalum nitride barriers are able to significantly block Li ion migration.

Lithium Mobility in Borate and Phosphate Glass Networks

Abstract In order to improve our understanding of the Li-mobility in oxide glass networks with Li as the principle mobile particle, electrical conductivity and self-diffusivity of lithium was studied in two phosphate (0.2 Li2O·0.8 P2O5, 0.3 Li2O·0.2 MgO·0.5 P2O5) and one borate (0.25 Li2O·0.75 B2O3) glass compositions. Conductivity measurements provided information about ion dynamics while isotope-exchange experiments involving isotopically enriched Li diffusion glass couples provided information about long-range diffusivity of Li-isotopes through borate and phosphate networks. Due to the limitations of individual glass stabilities, the temperature range for selected experiments was very small, e.g. as in the case of Li–phosphate composition between 373 and 520 K. The activation energy for Li-migration derived from conductivity measurements was similar for Li–Mg–phosphate and Li–borate, 90.4 and 85.2 kJ/mol, while for pure Li–phosphate the value was 74.7 kJ/mol. In the case of self-diffusion, the activation energies were comparable with Li–Mg–phosphate having the highest value of 76.9 kJ/mol while Li–phosphate and Li–borate had almost the same value of 72.9 and 72.2 kJ/mol, respectively. In these glass compositions with similar Li-cation concentration, the differences in the mobility predominantly depend on structural arrangement of building units and the spatial distribution of negative potentials, as reflected in the value of H R/f, i.e. the Haven ratio divided by the correlation factor, as a mean to better understand the diffusion mechanism in glass structures, where vacancy vs. interstitial diffusion cannot be clearly defined. For Li–phosphate almost unconstrained Li-migration was indicated with the H R/f value of 0.98, while Li–Mg–phosphate had the most structural constraint on mobilized Li-cations, with the H R/f value of 0.30. Findings are compared with silicate (Li2O·3 SiO2) and aluminosilicate (Li2O·Al2O3·4 SiO2) glasses from our previous studies in order to elaborate the effect of network topology.