Partial Substitution Of Ti Research Articles

Preparation of Si3N4–TiN–SiC composite by partial substitution of Ti–Si–Fe alloy for Si under N2 atmosphere

Preparation of Si3N4–TiN–SiC composite by partial substitution of Ti–Si–Fe alloy for Si under N2 atmosphere

Ti–S antibonding coupling enables enhanced bandgap tuning in Ti-substituted BaHfS3 perovskite

Chalcogenide perovskites have been proposed as one of the most promising candidates for solar cells due to their suitable bandgap, nontoxicity, and environmental stability. As a typically distorted perovskite, although BaHfS3 possesses extraordinarily strong light absorption near the band edge, the slightly large bandgap of ∼2.1 eV has limited its applications in photoelectronic. In this work, the Ba(Hf1−xTix)S3 (0 ≤ x ≤ 0.05) perovskites with good crystallinity were first successfully synthesized and exhibited a reduced bandgap from 2.01 to ∼1.4 eV. Moreover, it is striking that the bandgap sharply decreases to 1.52eV (24 % compared to undoped compound) with only 1 atom % Ti-alloying concentration. The Density functional theory calculation shows that the contribution of Ti near the conduction band minimum (CBM) increases through the partial substitution of Ti for Hf. It is also demonstrated that the significant decrease in the bandgap is due to the downshift of the CBM caused by Ti–S antibonding coupling accordingly. This study provides a promising Ti-substituted BaHfS3 material with excellent ambient and thermal stability, which can promote the use of chalcogenide perovskites in photovoltaics.

Boosting Hydrogen Evolution Reaction by Phase Engineering and Phosphorus Doping on Ru/P-TiO2.

Synergistic optimization of the elementary steps of water dissociation and hydrogen desorption for the hydrogen evolution reaction (HER) in alkaline media is a challenge. Herein, the Ru cluster anchored on a trace P-doped defective TiO2 substrate (Ru/P-TiO2 ) was synthesized as an electrocatalyst for the HER; it exhibited a commercial Pt/C-like geometric activity and an excellent mass activity of 9984.3 mA mgRu -1 at -0.05 V vs. RHE, which is 34.3 and 18.7 times higher than that of Pt/C and Ru/TiO2 , respectively. Experimental and theoretical studies indicated that using a rutile-TiO2 -crystal-phase substrate enhanced the HER activity more than the anatase phase. Rich surface oxygen vacancies on rutile-TiO2 facilitated the adsorption and dissociation of water, while the partial substitution of Ti4+ with P5+ enhanced H2 generation by facilitating hydrogen spillover from the Ru site to the surface P site, synergistically enhancing the HER activity.

Boosting Hydrogen Evolution Reaction by Phase Engineering and Phosphorus Doping on Ru/P‐TiO2

AbstractSynergistic optimization of the elementary steps of water dissociation and hydrogen desorption for the hydrogen evolution reaction (HER) in alkaline media is a challenge. Herein, the Ru cluster anchored on a trace P‐doped defective TiO2substrate (Ru/P‐TiO2) was synthesized as an electrocatalyst for the HER; it exhibited a commercial Pt/C‐like geometric activity and an excellent mass activity of 9984.3 mA mgRu−1at −0.05 V vs. RHE, which is 34.3 and 18.7 times higher than that of Pt/C and Ru/TiO2, respectively. Experimental and theoretical studies indicated that using a rutile‐TiO2‐crystal‐phase substrate enhanced the HER activity more than the anatase phase. Rich surface oxygen vacancies on rutile‐TiO2facilitated the adsorption and dissociation of water, while the partial substitution of Ti4+with P5+enhanced H2generation by facilitating hydrogen spillover from the Ru site to the surface P site, synergistically enhancing the HER activity.

Influence of partial substitution of Ti for Al on microstructure, thermal stability and corrosion resistance of novel quaternary Ni33.3Y33.3Al33.4-xTix medium entropy metallic glasses

In this present study, the influence of partial substitution of Ti for Al on microstructure, thermal stability and corrosion resistance of novel quaternary low-density Ni33.3Y33.3Al33.4-xTix (x = 3∼21 at.%) medium entropy metallic glass ribbons (ME-MG ribbons) was investigated. According to the rule of atomic radius similarity, by gradually replacing Al by Ti, we have synthesized a series of multi-component glassy alloy ribbons via using a single roller melt-spinning technique and also have examined their phase structure, thermal characteristics, microhardness and anti-corrosion properties. Besides, the phase composition of some representative annealed ribbon samples and the crystallization activation energy of these melt-spun ME-MG ribbons have been also determined and studied in detail. Results show that all of the rapidly solidified alloy ribbons can maintain completely amorphous nature. However, the thermal stability of ME-MG ribbons becomes reduced with the increasing Ti content. The maximum crystallization onset temperature at the heating rate of 20 K/min is around 706.65 K for Ni33.3Y33.3Al30.4Ti3 alloy ribbons. The maximum apparent activation energy of crystallization by means of thermodynamic analysis can be up to ∼803 kJ/mol for Ni33.3Y33.3Al21.4Ti12 alloy ribbons. The average microhardness value of these metallic ribbons can reach 455 HV0.1 or more when Ti content is less than 15 at.%, which is approximately 1.5 times the hardness of the Al-based amorphous alloy ribbons. The microstructural characterization of each ME-MG ribbon surface in as-received state and after a period of 45-hour and 75-hour corrosion immersion in 0.6 M NaCl solution was applied by scanning electron microscopy as well. Substituting moderately Al with Ti can effectively improve the anti-corrosion ability; the most positive pitting corrosion potential and the smallest corrosion current density are approximately -0.145 VSCE and 0.045 μA/cm2 for Ni33.3Y33.3Al24.4Ti9 and Ni33.3Y33.3Al27.4Ti6 ME-MG ribbons, respectively. Thus, it can be deduced that these new-fashioned ME-MG ribbons possess the superior anti-corrosion property, higher microhardness and acceptable thermal stability simultaneously, which may open momentous possibilities for the development and practical application of high-performance metal materials.

Solution-based fabrication of high-entropy Ba(Ti,Hf,Zr,Fe,Sn)O3 films on fluorine-doped tin oxide substrates and their piezoelectric responses

This paper reports the first fabrication of high-entropy Ba(Ti,Hf,Zr,Fe,Sn)O3 films on fluorine-doped tin oxide substrates through spin coating and hydrothermal synthesis. A homogeneous distribution of all constituent elements was observed through energy-dispersive x-ray spectroscopy mapping. High distortion (approximately 1.7%) of the lattice structure was caused by the underlying substrate and partial substitution of Ti with other larger elements of Hf, Zr, Fe, and Sn on B sites. Two types of Ba(Ti,Hf,Zr,Fe,Sn)O3 films were studied: high-density and slightly textured polycrystalline particles (Sample A), and randomly distributed [110]-oriented nanorods with marginal crystallinity (Sample B). In the piezoelectric experiment, Samples A and B substantially outperformed the medium-entropy oxide (MEO) samples and single-crystal ZnO bulk. Sample A also exhibited the highest piezoelectric coefficient (d33 ∼ 60 pm/V) among all studied samples. Its superior performance was attributable to a combination of high crystallinity, strong out-of-plane distortion, slightly textured polycrystalline structures, and cocktail effects. Furthermore, enhanced piezoelectricity was achieved after poling for the high-entropy oxide (HEO) and MEO samples, indicating their ferroelectric effect. The d33 of Sample A more than doubled (≈126.7 pm∙V−1), and the increase was substantially higher than that of Sample B. Our HEO samples have promise for use in piezoelectric- and ferroelectric-related applications.

Structural, magnetic, and electrical properties of Ti-doped La0.7Ba0.3Mn1-xTixO3 (0≤ x≤0.3) ceramics

The effect of Ti substitution at the Mn site on the structural, magnetic, and electrical properties of La0.7Ba0.3Mn1-xTixO3 (0≤x≤0.3) ceramics is studied. Samples are synthesized via a conventional solid-state reaction route. The analysis of X-ray diffraction data by using the FullProf Rietveld software confirms the phase transformation of these samples from an orthorhombic phase (0≤x≤0.1) to a rhombohedral one (0.2≤x≤0.3). The pristine sample (x = 0) undergoes paramagnetic to ferromagnetic transition characterization at the Curie temperature (TC) of 352 K and metal–insulator transition characterization at the transition temperature of 287 K. Partial substitution of Ti at the Mn site will not only decrease TC but is also expected to tune the electrical transport behavior of the system. Metal–insulator transition exists only in x = 0, x = 0.02, and x = 0.05 samples. By contrast, fully insulating behavior is observed in three remaining samples. The observed rapid decrease in TC could result from non-ferromagnetic Ti ions, which weaken the double-exchange interaction. The electrical resistivity data in metallic and insulating regions are analyzed using various conduction models. The nature of electronic transport in La0.7Ba0.3Mn1−xTixO3 (0.1 ≤ x ≤ 0.3) is studied.

Mesoporous titania–ceria mixed oxide (MTCMO): a highly efficient and reusable heterogeneous nanocatalyst for one-pot synthesis of β-phosphonomalonates via a cascade Knoevenagel–phospha-Michael addition reaction

Mesoporous titania–ceria mixed oxide (MTCMO) was synthesised in a sol–gel method using cerium chloride and titanium isopropoxide (TTIP) as CeO2 as well as TiO2 precursors and sodium dodecyl sulphate (SDS) as a structure-directing agent and its application was evaluated in the synthesis of aromatic β-phosphonomalonate derivatives via cascade Knoevenagel–phospha-Michael addition reaction. The catalyst characterised by various techniques like FT-IR spectroscopy, XRD, SEM, EDS, TEM and N2 adsorption-desorption. Partial substitution of Ti4+ cations with Ce4+ improved the BET surface area because TiO2 crystallites were suppressed to be grown. Furthermore, as a consequence of charge imbalance in the obtained Ti-O-Ce solid solution, some oxygen vacancies have generated that act as Lewis base sites while cations (Ti and Ce) around the oxygen vacancies act as Lewis acid sites. Reusability up to eight consecutive runs without significant decrease in reactivity, Mild reaction conditions, environmentally benign and compatibility with various functional groups are some of the advantages of this work.

Understanding the ultrahigh dielectric permittivity response in titanium dioxide ceramics

Dielectric materials with ultrahigh permittivity have attracted intensive interest due to the increasing demand of microelectronics and energy storage applications. In this work, for the first time we successfully synthesized zinc/magnesium and tungsten co-doped TiO2 dielectric ceramics with giant permittivity (εr ≈ 104) via ordinary mixed-oxide technique. The obtained ceramics are of pure homogenous rutile phase structure as verified by XRD and Raman spectroscopy; scanning electron microscopy studies indicate the very dense microstructure of them. Our detailed studies on dielectric performances imply that the partial substitution of Ti4+ by W6+ inhibits the generation of defect dipole and enhances the interface Maxwell-Wagner polarization, making the latter a dominant factor for the obtained giant permittivity. Our findings in this work might help to understand the physical origin of ultrahigh dielectric permittivity in (M0.5W0.5)xTi1-xO2-type (M = Mg or Zn) and other TiO2-based dielectric materials.

BaTi0.8B0.2O3 (B = Mn, Fe, Co, Cu) LNT Catalysts: Effect of Partial Ti Substitution on NOx Storage Capacity

The effect of partial Ti substitution by Mn, Fe, Co, or Cu on the NOx storage capacity (NSC) of a BaTi0.8B0.2O3 lean NOx trap (LNT) catalyst has been analyzed. The BaTi0.8B0.2O3 catalysts were prepared using the Pechini’s sol–gel method for aqueous media. The characterization of the catalysts (BET, ICP-OES, XRD and XPS) reveals that: i) the partial substitution of Ti by Mn, Co, or Fe changes the perovskite structure from tetragonal to cubic, whilst Cu distorts the raw tetragonal structure and promotes the segregation of Ba2TiO4 (which is an active phase for NOx storage) as a minority phase and ii) the amount of oxygen vacancies increases after partial Ti substitution, with the BaTi0.8Cu0.2O3 catalyst featuring the largest amount. The BaTi0.8Cu0.2O3 catalyst shows the highest NSC at 400 °C, based on NOx storage cyclic tests, which is within the range of highly active noble metal-based catalysts.

Mixed Ti-Zr metal-organic-frameworks for the photodegradation of acetaminophen under solar irradiation

Mixed Ti-Zr metal-organic-frameworks (MOFs) have been synthesized and tested as photocatalysts under solar-simulated radiation using acetaminophen (ACE) as target pollutant. These materials were obtained upon partial substitution of Ti by Zr atoms in the crystalline structure of NH2-MIL-125(Ti) MOF. The effect of the Ti:Zr molar ratio on their characteristics and catalytic behaviour has been analysed. Materials with high Zr relative amount (60–80%) showed amorphous structure and low solar-photocatalytic activity. In contrast, lower Zr proportions resulted in new MOFs with well-defined crystalline structure and high activity for the solar photocatalytic degradation of ACE, even higher than that of the bare Ti MOF. Results with scavengers allowed concluding that O2− radicals are the main reactive species, although photogenerated OH radicals and electrons also contribute to the degradation. The stability of the most active photocatalyst was confirmed upon three successive runs.

Controlling trapping states on selective theranostic core@shell (NaYF4:Yb,Tm@TiO2-ZrO2) nanocomplexes for enhanced NIR-activated photodynamic therapy against breast cancer cells.

Photodynamic and immune therapies are innovative medical strategies against cancer, and their integration with upconversion nanoparticles (UCNPs) can improve the diagnosis and treatment of the disease. The UCNPs convert the deep penetrating near-infrared (NIR) light into higher energy emissions, allowing the imaging and detection of malignant cells and the simultaneous energy transfer for activation of the photosensitizers. In this work, the UCNPs were coated with a photocatalytic TiO2/ZrO2 shell and an increase of oxygen defects (VO) was observed as a result of the partial substitution of Ti4+ by Zr4+ ions in the crystalline lattice of TiO2. Such defects act as trapping states improving charge separation and then reducing the recombination rate of the electron-hole pairs (e-/h+) generated upon resonant energy transfer from the donor (UCNPs) to acceptors (shell). The overall results are the enhancement of both ROS production and the emission band centered at 801 nm which is useful for tracking cells at the deep tissue level. However, an excess of those defects produces deleterious effects on both processes as a result of charge migration. The specificity against HER2 positive breast cancer was provided by bioconjugation with the monoclonal antibody trastuzumab. After administration of the synthesized NaYF4:Yb,Tm@TiO2/ZrO2-trastuzumab theranostic nanocomplex doped with an optimal ZrO2 molar concentration (25%) and subsequent exposure to 975 nm light (0.71 W cm-2) during 5 minutes, HER2-positive SKBr3 breast cancer cells were suppressed with 88% drop of the cell viability, 28% higher than UCNPs decorated with a pure TiO2 shell.

Effect of partial substitution of Ti for Al on the phase structure and electrochemical hydrogen storage properties of Mg3AlNi2 alloy

Ti was introduced into Mg3AlNi2 to partly substitute Al to improve the electrochemical hydrogen storage properties. Several alloys, namely Mg3Al1-xTixNi2 (x = 0, 0.2, 0.4, 0.6), were prepared by pretreatment of ultrasonic dispersion and high energy ball milling, followed by sintering. X-ray diffraction study indicates that all the alloys show multiphase structures. Galvanostatic charge and discharge experiments show that the maximun discharge capacity and the cycle stability of Mg3AlNi2 alloy electrode are significantly improved after partial substitution of Ti for Al. Field emission scanning electron microscopy was performed to directly observe the surface morphology evolution of the alloys before and after 50 charge-discharge cycles in electrolyte in order to investigate the anti-pulverization ability, while Tafel polarization was carried out to study the anti-corrosion ability. Our results show that the discharge capacity degradation of the Mg3Al1-xTixNi2 (x = 0, 0.2, 0.4, 0.6) alloys is mainly attributed to the pulverization of alloy particles in electrolyte. The high rate discharge ability of the alloys can also be remarkably enhanced by proper substitution of Ti for Al. Potentiostatic discharge, linear polarization and electrochemical impedance spectra were carried out to further investigate the kinetic properties, and it was found that proper substitution of Ti for Al could greatly improve surface activity and hydrogen diffusion ability of the Mg3AlNi2 electrode alloy.

Effect of Multiple Alloying Elements on the Glass-Forming Ability, Thermal Stability, and Crystallization Behavior of Zr-Based Alloys

Effect of multiple alloying elements on the glass-forming ability, thermal stability, and crystallization behavior of Zr-based glass-forming alloys were studied in the present work. We investigated the effect of complete or partial substitution of Ti and Ni with similar early and late transition metals, respectively, on the glass-forming ability and crystallization behavior of the Zr50Ti10Cu20Ni10Al10 alloy. Poor correlation was observed between different parameters indicating the glass-forming ability and the critical size of the obtained glassy samples. Importance of the width of the crystallization interval is emphasized. The kinetics of primary crystallization, i.e., the rate of nucleation and rate of growth of the nuclei of primary crystals is very different from that of the eutectic alloys. Thus, it is difficult to estimate the glass-forming ability only on the basis of the empirical parameters not taking into account the crystallization behavior and the crystallization interval.

Compositional analysis on the reverted austenite and tempered martensite in a Ti-stabilized supermartensitic stainless steel: Segregation, partitioning and carbide precipitation

Controlling the amount of reverted austenite at room temperature allows for tailoring of mechanical properties in supermartensitic stainless steels. The austenite reversion and stabilization occurs during inter-critical tempering through partitioning of austenite-stabilizing elements. The degree of partitioning greatly depends on the reversion temperature, which dictates the local equilibrium conditions. Atom probe tomography and energy dispersive spectroscopy in transmission electron microscopy were used to study the austenite reversion mechanism in terms of the elemental distribution of austenite-stabilizing, ferrite-stabilizing and carbide forming elements. Synchrotron X-ray diffraction confirmed that the austenite equilibrium phase fraction was reached after 2.5h of isothermal reversion at 625°C, allowing for direct comparison with thermodynamic and kinetic calculations. However, such soaking time was not enough to produce compositional homogenization in the reverted austenite. The austenite reversion and stabilization mechanism was related mainly to strong partitioning of Ni. Negligible partitioning of Cr, Mo, Si and Ti were observed. Instead, these elements were strongly segregated at the reverted austenite/martensite interfaces. Carbon and Ti played a secondary role in the austenite stabilization through the precipitation of nano-sized Ti (C,N) with partial substitution of Ti by Mo. Virtually carbon-free austenite and martensite were observed away from the interfaces and precipitates.

Synthesis and Superconductivity of Electron-Doped β-ZrNCl with Partial Substitution of Ti on Zr Site

Highly crystallized α-TiNCl and ZrNCl with orthogonal network of [M 2 N 2] (M: Ti and Zr) were used to synthesize the solid-solution phase α-Ti y Zr1−y NCl, which was irreversibly transformed into its β-form polymorph with honeycomb network upon a heat treatment. The intercalation of lithium (Li) into the obtained powder samples was carried out to realize the electron doping in β-form compound. The measurements of magnetic susceptibility and electrical resistivity suggest that the intercalated compound β-Li0.43Ti0.09Zr0.91NCl shows superconductivity with transition temperature (T c ) of 15.0 K. Upon the cointercalation of solvent molecule of tetrahydrofuran (THF), two transitions were observed at 14.1 and ∼21 K, corresponding to the main phase of β-Li x (THF) y ZrNCl and a THF-cointercalated phase of β-Ti y Zr1−y NCl, respectively. We consider that such a tiny substitution of Ti on Zr site in β-form structure play an important role in the increase of T c .

Improved photochemical properties of Aurivillius Bi5Ti3FeO15 with partial substitution of Ti4+ with Fe3+

Abstract This work improved the optical absorption and photocatalytic ability of four-layered Aurivillius Bi5Ti3FeO15 through microstructural modification via partial substitution of Ti4+ with Fe3+. Bi5Ti3−xFe1+xO15 (x = 0–0.6) photocatalysts were prepared through sol-gel citrate-complexation synthesis. The sample crystallized into plate-like nanoparticles with [001] facets. Phase formation and crystal structure were confirmed via X-ray powder diffraction (XRD) Rietveld refinements. Bi5Ti3−xFe1+xO15 (x = 0–0.6) maintained its structural characteristic, i.e., a perovskite unit of (Bi3Ti3−xFe1+xO13)2– sandwiched by two (Bi2O2)2+ layers along c axis. The samples were investigated via scanning electron microscope (SEM), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX), and specific surface area analyses. The band gap showed characteristic transitions from the valence band (VB) of (O2p+Fet2 g+Bi6s) to the conduction band (CB) of (Ti-3d+Fe-eg). With increasing substitution of Ti4+ with Fe3+, the sample greatly red shifted its absorption edges. The d–d transitions in FeO6 greatly contribute to the narrow band-gap. Aurivillius is a potential photocatalyst and demonstrated photodegradation of Rhodamine B (RhB) under visible light irradiation (λ > 420 nm). Such photocatalytic activities were attributed to the special structural layer and the catalytic mediators of multivalent Ti4+/3+ and Fe3+/2+ ions in the perovskite slabs as confirmed by XPS measurements. Results suggested that substitution of Ti4+ with Fe3+ in an Aurivillius phase was an efficient method to modify the bandwidth and structure of Aurivillius phase. This phenomenon can be used as a strategy to improve the photochemical properties of Ti/Fe-containing Aurivillius phases.

Effect of Fe content on atomic and electronic structure of complex oxides Sr(Ti,Fe)O3 − δ

We present a study of the electronic and atomic structure of two series of SrTi1−xFexO3−δ (STFO) powders with different Fe content produced by two different methods, spray pyrolysis or modified Pechini synthesis, by means of soft X-ray absorption spectroscopy. Partial substitution of Ti by Fe atoms in SrTiO3 were found to cause asymmetric distortion of TiO6 octahedrons, which increases with increasing Fe content that may violate the cubic symmetry of STFO. The presence mainly of Fe3+states in octahedral environment at small concentration of Fe atoms along with essentially smaller content of Fe4+ states in octahedral environment where the latter contribution increases with increasing Fe content was traced. It is found that the modified Pechini method allows to synthesize more stable structures but a tendency of the SrOx formation in the structure prepared by this technique was marked. The spray pyrolysis method gives the structure free of SrO precipitates but the presence of Fe3+ states in tetrahedral environment with Fe content higher than 50% and even a certain amount of Fe2+ ions in an octahedral environment at concentrations higher than 75% in the STFO prepared by this method was established. The O1s (K)-absorption spectra point to increase in oxygen vacancy concentration with increasing Fe content. The lowest degree of structure distortions with enough high oxygen vacancy concentration was traced in STFO (x=0.25 to x=0.35) produced by modified Pechini synthesis, which makes it mostly appropriate for technical applications, e.g., as gas sensors, oxygen separation membranes or as fuel cell material.

Molybdenum substitution at the B-site of lanthanum strontium titanate anodes for solid oxide fuel cells

The effects of Mo doping into the B-site of La0.3Sr0.7TiO3-δ perovskite on its ionic conductivity and catalytic activity as an anode material of solid oxide fuel cells have been investigated. The partial substitution of Ti by Mo reduces the bond energy between metal and oxygen ions in the perovskite. The concentration of Mo5+/Mo6+ redox couples increases with the rise of the content of Mo, while the oxygen ionic conductivity decreases simultaneously. The doping of Mo significantly reduces the anodic polarization resistance and improves the performance of the single cell. The cell with La0.3Sr0.7Ti0.97Mo0.03O3-δ anode and La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte exhibits a maximum power density of 135 mW cm−2 at 850 °C with hydrogen as fuel.

Cation Miscibility and Lithium Mobility in NASICON Li1+xTi2-xScx(PO4)3 (0 ≤ x ≤ 0.5) Series: A Combined NMR and Impedance Study.

Rhombohedral NASICON compounds with general formula Li1+xTi2-xScx(PO4)3 (0 ≤ x ≤ 0.5) have been prepared using a conventional solid-state reaction and characterized by X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and impedance spectroscopy. The partial substitution of Ti4+ by Sc3+ and Li+ in pristine LiTi2(PO4)3 increases unit-cell dimensions and the number of charge carriers. In Sc-rich samples, the analysis of XRD data and 6Li/7Li, 31P, and 45Sc MAS NMR spectra confirms the presence of secondary LiScO2 and LiScP2O7 phases that reduce the amount of lithium incorporated in the NASICON phase. In samples with x < 0.3, electrostatic repulsions between Li ions located at M1 and M3 sites increase Li mobility. For x ≥ 0.3, ionic conductivity decreases because of secondary nonconducting phases formed at grain boundaries of the NASICON particles (core-shell structures). For x = 0.2, high bulk conductivity (2.5 × 10-3 S·cm-1) and low activation energy (Ea = 0.25 eV) measured at room temperature make Li1.2Ti1.8Sc0.2(PO4)3 one of the best lithium ionic conductors reported in the literature. In this material, the vacancy arrangement enhances Li conductivity.