Lithium Borate Research Articles

Band gap determination by Tauc’s, ASF and DASF methods of alkaline earth modified lithium borate glasses co-doped with transition metal ions

In the current manuscript the inorganic glassy system with composition 15Li2O-25RO-59B2O3-0.7CuO-0.3Fe2O3 (R = Ca/Sr/Ba) have been synthesized through classical melt-quench method and investigated by XRD, and optical absorption techniques. The X-ray diffraction images of the synthesized glassy materials substantiated the inorganic glassy structure. The UV–Visible optical absorption spectra of the synthesized glassy materials were recorded with in the wavelength range 300 to 900 nm. The Tauc’s, ASF and DASF methods were employed to ascertain the optical and Urbach energies of the prepared glass system. The effect of alkaline earths on the optical absorption was discussed.

Mineralogy and Geochemistry of some Phosphate Deposits for Possible Rare Earth Elements Mineralization Potentials within Sokoto Basin, Northwestern Nigeria

Objective: Phosphate rocks found in some parts of Sokoto Sedimentary basins in Nigeria were studied to understand their mineralogy and geochemistry specifically to determine their abundance in Rare Earth Elements hosting minerals notably Apatite, Monazite and Xenotime as there is an increasing demand for these elements globally in the production of green technology. Methods: Field observations were carried out in places with reported phosphate occurrences and seven (7) representative phosphate samples were collected, crushed, pulverized, and analyzed using X-Ray Diffraction (XRD) analysis for their mineralogical composition while samples with significant fluorapatite concentrations were further analyzed with Lithium Borate fusion Inductively Coupled Plasma Mass Spectrometry (ICPMS) for their elemental composition. Findings: The phosphates typically occur as nodules intercalated with Shale occurring at depth of about 0.25 – 7m with a mineralogical composition including Fluoroapatite, Calcite, Smectite, Quartz, Kaolinite, Goethite, and Palygorskite. A high concentration of Fluorapatite was observed at Miyal’yako (79.28%) and Dillingo (36.60%) while interpretation of the relationship between P2O5 with other major oxides and trace elements revealed that the phosphates were primary type and typically formed in an oxidizing environment with fluctuating pH in the presence of calcite or gypsum. Novelty: The study pinpoints that, of the seven locations, only two showed high concentrations of fluoroapatites enough to suggest that they are areas of interest for further investigation in the search for REEs mineralization in Nigeria. Keywords: Rare Earth Elements; Phosphate; Mineralisation; Fluorapatite; Sokoto

The structure of glasses M2O-B2O3 (М – Li, Na, K): Estimation of thermodynamic characteristics of alkali borates and physicochemical modeling

The paper presents results of structural calculations carried out on the alkali borate glasses using physicochemical modeling based on Gibbs energy minimisation. Standard heat capacity, entropy and enthalpy of formation values for lithium, sodium and potassium borates are estimated by regression analysis for use as the input data for the models taking into account the error of the initial data. The correction of the physicochemical model was made using results of Raman spectroscopy. The dependence of the maximum of the “borate anomaly” on the number of non-bridging oxygen atoms was shown. It was found that the most obvious changes in the dependence of properties occur in the regions of N1 and N2 compositions, which are characterized by the appearance of asymmetric triangles BØ2O− and BØO22− in glasses, correspondingly.

Properties of trifluoromethylated lithium borates for lithium-ion battery electrolytes

Lithium salts govern important characteristics of lithium-ion batteries, including their efficiency (ion conductivity), operating voltage (potential window), and thermal stability. Herein, a series of lithium borates (lithium difluoro(perfluoropinacolato)borate (PFP-F2), lithium difluoro(2-hydroxy-3,3,3,3ʹ,3ʹ,3ʹ-hexafluoroisobutirato)borate (HHIB-F2), lithium (perfluoropinacolato)(oxalato)borate (PFP-Ox), lithium bis(2-hydroxy-3,3,3,3ʹ,3ʹ,3ʹ-hexafluoroisobutirato)borate (HHIB2), and lithium (2-hydroxy-3,3,3,3ʹ,3ʹ,3ʹ-hexafluoroisobutirato)(oxalato)borate) containing CF3 and C=O groups were developed as potential electrolytes for lithium-ion batteries. The proposed lithium borates were synthesized in good purity from lithium tetrafluoroborate and lithium difluoro(oxalato)borate using trimethylchlorosilane and three types of bidentate ligands in ethylmethylcarbonate. The applicability of the novel lithium borates as electrolytes for lithium-ion batteries was demonstrated based on thermal and electrochemical stability evaluations. In addition, lithium borates with >4 CF3 groups (PFP-F2, PFP-Ox, and HHIB2) exhibited outstanding stability against hydrolysis (water contamination). HHIB-F2 showed the best ionic conductivity owing to the balanced incorporation of increased Li+ dissociation and mobility by introducing the CF3 group and reducing the anion size. HHIB-F2 and HHIB2-containing electrolytes showed better cycle performance than their conventional BF4 counterparts. This study suggests that the new lithium borates, HHIB2, and HHIB-F2, are promising lithium salts for lithium-ion batteries, providing a new direction for the lithium salt molecular design.

Structural analysis of Eu3+ in Li2O-MO-B2O3-Eu2O3(M=Mg, Ca, Sr, Ba) glass using XANES and EXAFS

The research focuses on the structural changes, coordination and interatomic distance of Europium doped Li2O-MO-B2O3 (M = Mg, Sr) glasses. The detailed analysis was subjected to understand Eu3+ ions in lithium magnesium borate and lithium strontium borate glasses as determined by the extended X-ray absorption fine structure analysis. XANES spectra of Eu2O3 content doped in the present glasses showed Eu3+ state upon the x-ray as incident source. The metal LIII edges, and K edges are investigated concerning alkaline earth ion glasses and their interactions with local environment. In this work, europium and barium ions in lithium borate glasses are studied by LIII-edges, strontium and calcium ions in lithium borate glasses are studied by K-edges using X-ray absorption spectroscopy to reveal the relationship between alkali earth metal ions with Eu3+, Ba2+, Ca2+, and Sr2+ ion local structure. The nearest neighbors of Eu for the first shell were analyzed for Eu–O distance in Eu3+-doped glasses by EXAFS analysis and found to be in the range of 2.35–2.36 Å. Judd-Ofelt analyses were performed, and JO parameters showed Ω4> Ω2> Ω6 trend for Mg, Ca, Sr in lithium borate glasses while a Ω2> Ω4> Ω6 trend for Ba in lithium borate glasses. Radiative properties were analyzed using JO parameters to calculate stimulated emission cross-section, branching ratio, and radiative lifetime. The calculation was also taken care of with thermal correction and found that the data obtained after thermal correction shows higher values.

Structural, electrical and optical properties of carbon nanoparticle-lithium borate glass composites

The present study reports the structural, optical, and ionic transport characteristics of carbon nanoparticle (CNP)-lithium borate glass composites synthesized via melt-quenching technique. The composites were characterized using high-resolution transmission electron microscopy, field-emission scanning electron microscopy, Raman spectroscopy, Ultraviolet–visible spectroscopy, and impedance analysis at different temperatures. The ionic conductivity at room temperature was found to increase from 7.08 × 10−7 S/cm to 1.57 × 10−6 S/cm and the direct and indirect band gap energies shrank from 3.61 eV to 3.44 eV and 2.86 eV to 2.08 eV respectively with the addition of 0.4 wt% of CNPs compared to the pristine glass. The structural modifications that occurred in the glass network with the inclusion of CNPs accounted for this improvement.

Lithium Borate Ionic Liquids as Single‐Component Electrolytes for Batteries

AbstractCurrent electrolytes for lithium batteries are usually composed of at least two chemical compounds, an organic solvent such as a cyclic carbonate and a lithium salt such as LiPF6. Here, the concept of using a single‐component electrolyte is demonstrated in lithium batteries based on new lithium borate ionic liquids at room temperature. The design concept of this class of lithium ionic liquids (LiILs) is based on an asymmetrically substituted central tetracoordinate boron atom with oligoethylene glycol groups, fluorinated electron‐attracting groups, and one alkane group. The optimized borateLi+ LiILs show a high ionic conductivity value of >10−4 S cm−1 at 25 °C, high lithium transference numbers ( = 0.4 – 0.5) and electrochemical stability (>4 V). Some of the LiILs present high compatibility with lithium‐metal electrodes showing stable polarization profiles in platting/stripping tests. The selected LiIL is investigated as single‐component electrolytes in lithium‐metal battery cells showing discharge capacity values in Li0/LiIL/lithium–iron phosphate and Li0/LiIL/lithium titanate cells of 124 and 75 mAh g−1, respectively, at a C‐rate of 0.2 C and 65 °C with low‐capacity loss.

Microscopic and radioanalytical investigation of asbestos-containing decommissioning waste

During decommissioning of nuclear facilities, possibly contaminated asbestos containing materials (ACM) emerge. In this work, we propose an analytical method to characterize ACM contaminated with alpha and beta nuclides by microscopic (light and electron microscopy) and radioanalytical techniques. For this purpose, a chromatographic separation is applied after decomposition of ACM by a lithium borate fusion at 1065 °C. The subsequent separation is performed with UTEVA-TRU-Sr chromatographic resins. Recovery rates for analyzed radionuclides were on an average of 80–90% for Am, Cm, Pu isotopes, and Sr-90. Compared to sample pre-treatment with hydrofluoric acid, the lithium borate fusion proves more suitable, while providing higher working safety.

Towards guided metallic ions migration in network glass-formers: The Positronics approach in application to lithium tetraborate glass

The Positronics approach grounded on positron annihilation lifetime spectroscopy treated in terms of x3-x2-CDA (coupling decomposition algorithm) is used to recognize nanostructurization-driven volumetric effects in lithium tetraborate glass g-Li2B4O7 under transition to crystalline state, doping by Ag and/or Gd activators and 2-h above-Tg annealing in air environment. Lithium vacancies and vacancy complexes are shown to be principal free-volume elements responsible for positron trapping and decaying of bound positron-electron (positronium, Ps) states in these glasses. Expected devitrification (glass-to-crystal) transition corresponds to direct (Ps-to-positron) trapping conversion in volume-contracted network due to transformation of Ps-hosting sites in positron traps.Plausible migration scenarios for metallic activators in g-Li2B4O7 include occupation of vacancy-type positron traps and Ps-decay holes by Ag+ and/or Gd3+ ions, totally reducing positron-trapping and Ps-decaying contributions. Effect of thermal annealing in metal-doped lithium tetraborate glass is not related to simple de-occupation of vacancy-type defects due to escape of Ag + or Gd3+ ions. Annealing-stimulated transformations are guided by relaxation towards defect-free glass structure, being disturbed by competitive defect formation and destruction processes accelerated by interaction with oxygen. Since non-elementary nature of trapping-modification processes in doped glasses subjected to annealing, the formalism of x3-x2-CDA cannot be reasonably applicable.

Preliminary chemical and mineralogical characterization of tailings from base metal sulfide deposits in Serbia and North Macedonia

Tailings of old mines often contain metals, which were not of economic interest or could not be recovered with the existing technology at the time of active mining. This is especially true for metals that often occur as by-products in Cu-Pb-Zn-(Ag-Au) ores as Sb, Mo, Ge, and In. A fundamental characterization of some tailings is presented in terms of their mineralogy and content of valuable metals which could be extracted to finance a possible remediation and improve the supply of the EU with critical metals. Tailings from active and abandoned mines in Serbia (Bor, porphyry Cu/Au; Krivelj, porphyry Cu/Au; Blagodat, hydrothermal Pb-Zn; Lece, epithermal Au; Rudnik, hydrothermal/skarn Pb-Zn) and North Macedonia (Sasa, Pb-Zn; Probištip, Pb-Zn; Bučim, porphyry Cu; Lojane, fault-bound vein-type low-temperature As, Sb, Cr at the contact of rhyolite and serpentinite) were studied. Analysis for major and trace elements used a multi-method approach (lithium borate fusion and ICP-MS/OES analysis, gravimetric analysis, instrumental neutron activation analysis, total digestion ICP-OES, infrared spectroscopy) with mineral identification by scanning electron microscopy. Concentrations of the major commodity elements (Cu, Pb, Zn, Au, Ag) varies within several orders of magnitude depending on mineralogy and ore type. Critical metals (Co, Ga, Ge, Sb) contents are low with some exceptions. Some tailings contain moderate to elevated potentially toxic element levels (As, Cd, Pb, Tl). For the sample from Probištip which yielded the highest valuable metal concentrations (>5000 ppm Pb, 4020 ppm Zn), a heavy mineral concentrate of the sand size fraction (0.06 mm to 0.5 mm) was produced and analyzed by SEM and LA-ICP-MS for additional rare phases and trace elements. In all tailings studied, additional milling would be needed to separate ore from gangue minerals. Increasing metal prices might facilitate feasibility studies for some of the localities in the future, despite the limited quantitative information about the characterized tailings.

Gamma irradiation-induced changes in the structural, optical, electrical and radiation shielding properties of lithium borate glasses

Lithium borate glass with the chemical composition 25Li2O–75B2O3 (LBO) was prepared using the melt quenching technique. The changes in their structural, optical and electrical parameters due to gamma irradiation were investigated and its radiation shielding ability was discussed. The as-prepared glasses were transparent, colourless and inclusion free. The glasses were irradiated for 20, 40, 60, 80 and 100 kGy using a60Co gamma source having a dose rate of 2.906 kGy/h. As the radiation dose increases colour centres were formed in the LBO glass, for higher dosages the glasses turned black. The theoretical structural parameters such as density, optical basicity, ionicity, boron-boron separation, bond density, molar volume and oxygen packing density were calculated. The structural changes were carried out using x-ray diffraction confirming the amorphous nature even after a high dose of gamma irradiation. Gamma irradiation induces the formation of BO4. The bandgap decreases from 3.72 to 3.64 eV with an increase in the dose of gamma irradiation. The dielectric spectroscopy and A.C. conductivity mechanism of the glasses were analyzed. The activation energy of the glasses was calculated before and after gamma irradiation using the Arrhenius plot. High doses of gamma irradiation resulted in an increase in activation energy of LBO glasses which increases from 0.12 eV to 0.42 eV at 100 kHz frequency. The radiation shielding ability of the prepared glass samples was estimated using theoretical simulations by Phy-X/PSD software.

High power picosecond green and deep ultraviolet generations with an all-fiberized MOPA.

We demonstrate high power picosecond green and deep ultraviolet (DUV) lasers based on an all-fiberized master oscillator power amplifier (MOPA). The main power amplifier is fabricated with a highly Yb-doped large mode area (LMA) silicate glass fiber. It delivers 75.2-W laser output at 1029 nm with a pulse repetition rate of 10 MHz and a pulse duration of 70 ps. With a lithium triborate (LBO) crystal, a 43.0-W green output at 514.5 nm has been achieved with a pulse duration of 55 ps. With a caesium lithium borate (CLBO) crystal, a 14.5-W picosecond DUV output at 257 nm has been generated, which is the highest power for the all-fiber based DUV laser, to the best of our knowledge.

Nickel and manganese on lithium borate glass cathode for energy storage materials

In this work, co-doped nickel and manganese ions in lithium-borate-based glass (xNiO-yMnO:0.8LBO) were successfully fabricated with different Ni and Mn ratios and studied their structure and function relationship, especially on electrochemical properties. All fabricated glasses were amorphous phase, observed by XRD and TEM techniques. Optical band gaps ranging from 3.336 to 3.539 eV were found in prepared glass system. The oxidation state of Ni2+ and the mixing of Mn2+/3+ were clearly observed using XPS technique and synchrotron-based XANES technique. Additionally, the Ni and Mn K-edge EXAFS analysis exhibited a co-existence of octahedral site structure (A-site) and tetrahedral site structure (B-site) in all glasses with a different proportional site. By electrochemical studies, the specific capacitances of these glass system significantly increased with increasing Ni contents in glass composition. Interestingly, the highest specific capacitance value of 81.57 F.g–1 was obtained for NM31 (0.15NiO-0.05MnO:0.8LBO) glass sample suggesting a new promising glass electrode in future Li-ion battery.

Alkali and alkaline earth zinc and lead borate glasses: Structure and properties

Low melting Li 2 O-PbO-B 2 O 3 , Me 2 O-ZnO-B 2 O 3 , Me = Li, Na, K, Rb and CaO-ZnO-B 2 O 3 glasses were studied with Raman and infrared spectroscopies to advance the structural understanding of zinc borate glasses as potential candidates for substitution of lead containing glasses. Although the effect of type of alkali ions on the number (N 4 ) of fourfold coordinated boron (B 4 ) in the glasses is small, the alkali ions direct the type of borate groups, i.e., pentaborate in lithium, sodium, and calcium zinc borate glasses, as well as diborate in potassium and rubidium containing ones. Both groups were simultaneously found in Li 2 O-PbO-B 2 O 3 . Alkali ions are mainly responsible for the formation of B 4 -units and metaborate. Zinc ions favorably compensate non-bridging oxygen and partially form ZnO 4 . With decreasing N 4 and field strength of the alkali ions the atomic packing density, glass transition temperature and Young's Modulus also decrease. The coefficient of thermal expansion increases with decreasing N 4 . • In alkali-zinc-borate glasses alkali ions mainly neutralize the charge of B 4 -units. • Zinc ions favorably compensate the charge of non-bridging oxygens in the glasses. • The number of tetrahedral boron depends on the nature of the network-modifier. • The type of alkali ion and Zn or Pb ion directs the formation of borate units. • Alkali-glasses reflect a decrease of Young's Modulus with atomic packing density.

The dual role of bismuth in Li2O–Bi2O3–B2O3 glasses along the orthoborate join

AbstractThe structures of glasses in the lithium–bismuth orthoborate composition range deviate significantly from the short‐range order structure of the two crystalline end‐members. Although binary Li3BO3 and BiBO3 are solely of comprised trigonal orthoborate anions, all glasses formed by their combination contain four‐coordinated borate tetrahedra. We analyze the structure of (75−1.5x)Li2O–xBi2O3–(25+0.5x)B2O3 glasses in increments of x = 5, with 11B magic‐angle spinning nuclear magnetic resonance (NMR), infrared (IR), and Raman spectroscopy. For the full series, the oxygen‐to‐boron ratio remains constant at O/B = 3:1. NMR quantifies an increase in the fraction of tetrahedral boron with increasing bismuth oxide content. Evolution of the mid‐IR profile suggests multiple types of tetrahedral boron sites. Raman spectroscopy reveals that Bi2O3 tends to cluster within the lithium borate matrix when initially introduced and that this behavior transforms into a bismuthate network with increasing bismuth oxide content. In all cases, mixed Bi–O–B linkages are observed. The dual role of bismuth as network modifier and network former is likewise observed in the far IR. The glass transition temperature continuously increases with bismuth oxide content; however, the glass stability displays a maximum in the multicomponent glass of x = 40.

Optically based dosimetry of high-energy radiation using the undoped lithium tetraborate crystals: Nonlinear features

The lithium tetraborate (LTB) optical characteristics studies, particularly the luminescence and phosphorescence after irradiation on the M − 30 microtron to create radiation defects, are presented. The investigation was conducted in a wide range of intensities of accelerated electrons, their energies within 7–15 MeV, and absorbed radiation doses.The threshold character and nonlinear influence of the radiation defects on the optical dosimetric characteristics of LTB were established when their concentration became comparable to that of intrinsic or structural defects. Undoped optical crystals LTB are a convenient target for this type of research. It is shown that the combination of optical data from the study of thermally stimulated luminescence and phosphorescence allows one to control the irradiation conditions: flux density and absorbed dose.The obtained results are important for radiation technologies that use high doses of radiation, and can also be taken into account when planning of dosimetric procedures in medicine using high-energy nuclear particles.

Effect of Ni content in lithium nickel borate glasses: Structure and electrochemical studies

To improve the cathode materials performance of Li-ion batteries, an effect of nickel content in lithium borate (xNi:LiBO3) glass systems was introduced. The physical, structural, magnetic and electrochemical properties of xNi:LiBO3 glasses with x = 0, 0.15, 0.20, and 0.25 were carefully studied. XRD, XAS, and XPS techniques were used to investigate the effect of Ni contents in all glass structures. A glass structural motif was clearly confirmed by XRD and TEM results with an absence of crystallization behavior. By VSM measurement, LiBO3 based glass samples exhibited diamagnetism, while Ni doped glass samples exhibited a mixing of paramagnetism and weak ferromagnetism. Interestingly, a mixing valence state of Ni2+ and Ni3+ was observed of all glasses and local bonding distances between Ni-O and Ni-Ni were discovered ranging of 1.98–1.99 Å and 2.72–2.86 Å, respectively. Surprisingly, electrochemical properties of prepared LiBO3 glasses could be enhanced by increasing the Ni content in glass structure. In this study, the 0.25Ni:LiBO3 glass electrode showed the highest specific capacitance of 91.06 F.g−1 at a scan rate of 5 mV/s, indicating that it could be a promising glass electrode for Li ion battery.

The effect of replacing copper metal or oxide with neodymium on the optical properties of lithium tetraborate glass

The melting quenching technique is used to create lithium tetraborate glasses with the following composition (in mol %): 80 Li2B4O7-(20-x) Nd2O3-x Cu metal or x CuO mol% (x = 0, 5, 10, 15, and 20). X-ray diffraction (XRD), optical absorption, photoluminescence, thermal analysis, and Fourier transmission infrared (FTIR) were studied. The optical absorption spectra indicate the presence of Nd3+ and Cu2+ ions. The absorption spectra determine the Judd–Ofelt intensity parameters (Ωλ), the oscillator strengths, and bonding parameters. The high value of Ω2 indicates the increasing covalent bonding within the host structure. The ratio between emission intensities and excitation indicates that glass samples are used as laser sources. The photoluminescence spectra revealed neodymium ion emission. The glasses containing 20 mol % Nd2O3 (free from copper) emitted light at 1053 nm. The strength of emission peaks decreases as copper concentration increases according to the quenching effect. The findings indicate that the samples investigated are suitable for use in solid-state lasers.

Thermal conduction in a densified oxide glass: Insights from lattice dynamics

Thermal conductivity is an important property of oxide glasses, but its structural origins remain largely unknown. Here, we provide detailed modal information on thermal conductivity in a calcium aluminosilicate glass by relying on recent advances in lattice dynamics methods. We probe various structural features using molecular dynamics simulations by densifying the glass at pressures up to 100 GPa and studying the vibrational, mechanical, and thermal properties. We demonstrate good agreement between these simulations and complementary experiments, both of which indicate significant pressure-induced alteration of mechanical moduli, vibrational density of states, boson peak behavior, and thermal conductivity. We also find an intriguing correlation between the boson peak frequency and the total thermal conductivity in both the current glass series and a lithium borate glass series reported in literature. This correlation scales with the Debye frequency, suggesting that both parameters are associated with the transformation of the elastic medium under pressure.

Utilizing Triethyl Phosphate to Increase the Solubility of Lithium Nitrate for Improved Silicon Anode Performance

An electrolyte consisting of lithium nitrate (LiNO3) and lithium difluoro(oxalto)borate (LiDFOB) in ethylene carbonate (EC), ethylmethyl carbonate (EMC), and triethyl phosphate (TEP) was used to improve the long-term cycling stability of silicon anodes. TEP was selected for its ability to dissolve LiNO3 in carbonates to a concentration of ~0.2 M. The large amount of LiNO3 combined with the LiDFOB salt led to a capacity retention of 87.1% after one hundred cycles due to the formation of a stable solid electrolyte interphase (SEI). Ex-situ surface analysis revealed that the SEI consists of oxalates, lithium alkyl carbonates, borates, and nitrate decomposition products. By selecting two components that preferentially reduce before the rest (LiNO3 and LiDFOB), the SEI formed was able to prevent significant solvent decomposition and allow for improved electrochemical cycling in pure silicon anodes.