Structural,electronic properties and chemical bonding in protonated lithium metallates Li<Subscript>2−<Emphasis Type="Italic">x</Emphasis></Subscript>H<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>MO<Subscript>3</Subscript> (M = Ti,Zr, Sn)

Within density functional theory by an ab initio molecular dynamics method (SIESTA code) the features of structural, electronic properties and chemical bonding in lithium metallates Li₂MO₃ (M = Ti, Zr, Sn) are studied, as well as of their protonated forms Li_2−x H _x MO₃ at all possible H⁺ → Li⁺ substitutions. With the use of the calculated crystal orbital overlap populations and the formation energies of Li_2−x H _x MO₃ the most preferred H⁺ → Li⁺ substitutions in Li₂MO₃ metallates are discussed.     

An electrochemical investigation on (MoO<Subscript>3</Subscript>+PVP+PVA) nanobelts for lithium batteries

Molybdenum trioxide (MoO₃) xerogel films modified with poly(vinyl alcohol)+poly(vinyl pyrrolidone) (PVP+PVA) polyblends were obtained by ion-exchange method with sol-gel technique. Investigations were conducted using X-ray “diffractometry”, Fourier transform infrared spectroscopy, and cyclic voltammetry. The results show that the H atoms in polyblend are H-bonded with the O atoms in the Mo=O bonds of MoO₃ xerogel, which effectively shield the electrostatic interaction between MoO₃ interlayer and Li⁺ ions when MoO₃ xerogel is modified by the intercalation of (PVP+PVA). The reversibility of the insertion/extraction of Li⁺ ions is greatly improved by the modification with polyblend of MoO₃ nanocomposite films. MoO₃ and (PVP+PVA) _x MoO₃ (x = 0, 0.5) nanobelts were obtained by a simple hydrothermal process from MoO₃ sol. The electrochemical cells with configuration Li/(LiPF₆+EC+DMC)/MoO₃ modified by (PVP+PVA) were fabricated and their discharge profiles studied.     

Preparation and ion-exchange properties of zirconium tungstoarsenate

A new inorganic ion-exchanger, zirconium tugnstoarsenate, has been synthesized which has been characterized by chemical analysis, thermogravimetry, X-ray and infrared spectroscopy. The ion exchanger has been found to be stable in acids and neutral salt solutions. The K_d values for 30 metal ions have been determined at pH 3–4 which show that the exchanger has high affinity for UO ₂ ²⁺ , ZrO²⁺, Cs⁺ and Tl⁺ ions. The variation of K_d for a number of metal ions as a function of concentration of nitric acid and ammonium nitrate has been investigated to elucidate the probable exchange mechanism and to work out conditions for elution. Some binary separations, viz. Sr²⁺−Cs⁺, Sr²⁺−Rb⁺, Sr²⁺−Y³⁺, Fe³⁺−Al³⁺, Fe³⁺−Zn²⁺ and Zn²⁺−Hg²⁺ in trace amounts have been carried out on the column of the exchanger which demonstrate the utility of the exchanger in radionalytical and analytical chemistry.     

Study of the Solid Solutions of LiNbO3and LiTaO3with Mn

Two unusual, extensive new solid solutions of LiNbO₃and LiTaO₃with MnO have been prepared, where 4Mn²⁺replace a combination of 3Li⁺and a pentavalent cation: Nb⁵⁺or Ta⁵⁺. The formulas are Li_1−xM_1−xMn_4xO₃, 0<x<0.13, forM=Nb and 0<x<0.23 forM=Ta. The solid solutions were characterized by X-ray powder diffraction and density measurements. The manganese oxidation states were determined by X-ray photoelectron spectroscopy.     

Study of ion transport processes in soils by radioabsorption method

The transport processes of Na⁺, K⁺, Cs⁺, Ca²⁺, Zn²⁺, Mn²⁺, Fe³⁺ and HPO ₄ ²⁻ ions were studied in soils by radioabsorption method. The effective diffusion coefficients varied in the interval of 10⁻¹⁶–10⁻¹⁰ m²s⁻¹. The effective diffusion coefficient of Ca²⁺, Co²⁺, Zn²⁺ and Fe³⁺ ions increased by several orders of magnitude as a result of the addition of a complex forming agent.     

Lithium-substituted cobalt oxide spinels LixM1−xCo2O4 (M = Co2+, Zn2+; 0 ≤ x ≤ 0.4)

Substitution of Li⁺ into Co₃O₄ and ZnCo₂O₄ gives rise to the solid solution series Li_xM_1?xCo₂O₄ (M = Co²⁺ or Zn²⁺) having the spinel structure upto x = 0.4. X-Ray diffraction intensities show that the spinel solid solutions are likely to have the following cation distributions: (Co²⁺)_t[Li⁺_xCo³⁺_2?3xCo⁴⁺_2x]₀O₄ and (Zn²⁺_1?xCo²⁺_x)_t[Li⁺_xCo³⁺_2?3xCo⁴⁺_2x]₀O₄. Electrical resistivity and Seebeck coefficient data indicate that the electron transport in these systems occurs by a small-polaron hopping mechanism.     

Effect of annealing atmosphere on structural,optical and electrical properties of Al-doped Zn<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Cd<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>O thin films

1 at.% Al-doped Zn_1−x Cd _x O (x = 0–8 at.%) thin films were prepared on glass substrates by sol–gel method. The codoping films retained the hexagonal wurtzite structure of ZnO, and showed preferential c-axis orientation. The effect of annealing ambient (in vacuum and nitrogen) on the optical and electrical properties of (Cd,Al)-codoped ZnO films were investigated using transmission spectra and electrical measurements. The transmittances of the codoping films were obviously degraded by vacuum annealing to 50–60 %, but enhanced to 70–80 % after nitrogen annealing. The carrier concentration and Hall mobility both increased, and resistivity decreased with narrowing band gap of Al-doped Zn_1−x Cd _x O, below different critical concentrations x = 4 % (in vacuum) and x = 6 % (in nitrogen). It is revealed that the conductivity is also improved by Cd doping along with band gap modification. The variations in optical and electrical properties are ascribed to both the changes of the crystallinity and concentration of oxygen vacancies under different ambient. In view of transmittance and conductivity, nitrogen annealing might be a more effective post-annealing way than vacuum annealing for our (Cd,Al)-codoped ZnO films to meet the requirements of transparent conducting oxide (TCO).     

Effect of metal substitution for cobalt on the oxygen adsorption properties of YBaCo<Subscript>4</Subscript>O<Subscript>7</Subscript>

YBaCo₄O₇ compound is capable to intake and release a large amount of oxygen in the temperature range of 200–400°C. In the present study, the effect of Zn, Ga and Fe substitution for Co on the oxygen adsorption/desorption properties of YBaCo₄O₇ were investigated by thermogravimetry (TG) method. Due to fixed oxidation state of Zn2+ ions, the substitution of Zn²⁺ for Co²⁺ suppresses the oxygen adsorption of YBaCo_4−xZn_xO₇. The substitution of Ga³⁺ for Co³⁺ also decreases the oxygen absorption capacity of YBaCo_4−xGa_xO₇. This can be explained by the strong affinity of Ga³⁺ ions towards the GaO₄ tetrahedron. Compared with Zn- and Ga-substituted samples, the drop of oxygen adsorption capacity is smallest for Fe-substituted samples because of the similar changeability of oxidation states of Co and Fe ions.     

Studies on phosphatidylserine by tandem quadrupole and multiple stage quadrupole ion-trap mass spectrometry with electrospray ionization: Structural characterization and the fragmentation processes

Low-energy CAD product-ion spectra of various molecular species of phosphatidylserine (PS) in the forms of [M−H]⁻ and [M−2H+Alk]⁻ in the negative-ion mode, as well as in the forms of [M+H]⁺, [M+Alk]⁺, [M−H+2Alk]⁺, and [M−2H+3Alk]⁺ (where Alk=Li, Na) in the positive-ion mode contain rich fragment ions that are applicable for structural determination. Following CAD, the [M−H]⁻ ion of PS undergoes dissociation to eliminate the serine moiety (loss of C₃H₅NO₂) to give a [M−H−87]⁻ ion, which equals to the [M−H]⁻ ion of a phoshatidic acid (PA) and give rise to a MS³-spectrum that is identical to the MS²-spectrum of PA. The major fragmentation process for the [M−2H+Alk]⁻ ion of PS arises from primary loss of 87 to give rise to a [M−2H+Alk−87]⁻ ion, followed by loss of fatty acid substituents as acids (R_xCO₂H, x=1,2) or as alkali salts (e. g., R_xCO₂Li, x=1,2). These fragmentations result in a greater abundance of [M−2H+Alk−87−R₂CO₂H]⁻ than [M−2H+Alk−87−R₁CO₂H]⁻ and a greater abundance of [M−2H+Alk−87−R₂CO₂Li]⁻ than [M−2H+Alk−87−R₁CO₂Li]⁻; while further dissociation of the [M−2H+Alk−87−R_{2(or 1)}CO₂Li]⁻ ions gives a preferential formation of the carboxylate anion at sn-1 (R₁CO₂⁻) over that at sn-2 (R₂CO₂⁻). Other major fragmentation process arises from differential loss of the fatty acid substituents as ketenes (loss of R_x′CH=CO, x=1,2). This results in a more prominent [M−2H+Alk−R₂′CH=CO]⁻ ion than [M−2H+Alk−R₁′CH=CO]⁻ ion. Ions informative for structural characterization of PS are of low abundance in the MS²-spectra of both the [M+H]⁺ and the [M+Alk]⁺ ions, but are abundant in the MS³-spectra. The MS²-spectrum of the [M+Alk]⁺ ion contains a unique ion corresponding to internal loss of a phosphate group probably via the fragmentation processes involving rearrangement steps. The [M−H+2Alk]⁺ ion of PS yields a major [M−H+2Alk−87]⁺ ion, which is equivalent to an alkali adduct ion of a monoalkali salt of PA and gives rise to a greater abundance of [M−H+2Alk−87−R₁CO₂H]⁺ than [M−H+2Alk−87−R₂CO₂H]⁺. Similarly, the [M−2H+3Alk]⁺ ion of PS also yields a prominent [M−2H+3Alk−87]⁺ ion, which undergoes consecutive dissociation processes that involve differential losses of the two fatty acyl substituents. Because all of the above tandem mass spectra contain several sets of ion pairs involving differential losses of the fatty acid substituents as ketenes or as free fatty acids, the identities of the fatty acyl substituents and their positions on the glycerol backbone can be easily assigned by the drastic differences in the abundances of the ions in each pair.     

Electrochemically induced transformations of ruthenium(III) trichloride microcrystals in salt solutions

Ruthenium (III) trichlorid solid crystals have been mechanically attached to gold surfaces and studied by cyclic electrochemical quartz crystal microbalance measurements in the presence of aqueous solutions of different concentrations containing M⁺Cl⁻, where M⁺=H⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺. The RuCl₃ and the complexes formed during the electrochemical transformations show two or more reduction and reoxidation pairs of waves, depending on the experimental conditions (concentration, scan rate, and potential range). The voltammetric peaks are shifted into the direction of higher potentials with increasing electrolyte concentrations except at very high concentrations when the peaks belong to the first reduction/reoxidation processes move oppositely. The mass change was reversible, during reduction mass increase, while during oxidation mass decrease occurred at medium electrolyte concentrations in two, more or less distinct steps. At high or low concentrations the mass excursions are more complex involving different mass increase/decrease regions as a function of potential which vary with the potential range of the measurements. The peak potentials and the electrochemical activity strongly depend on the nature of the cations and pH. It is related to the formation of complexes in different compositions. The mass change decreases with increasing electrolyte concentrations attesting the important role of the water activity and the transport of solvent molecules. It was concluded that in dilute solutions during the first reduction step M⁺ ions enter the surface layer. The strongly hydrated Li⁺ ions transfer water molecules into the microcrystals, while simultaneously with the incorporation of K⁺, Rb⁺, and Cs⁺ ions H₂O molecules leave the surface layer. The opposite transport of ions and solvent molecules occur during oxidation. In the course of further reduction the incorporation of all ions studied except that of Cs⁺ ions is accompanied with water sorption. The number of sorbed water molecules is proportional to the hydration number of these ions. A reaction scheme is proposed in which M⁺ _m-3[Ru^IIICl _m (H₂O) _n ]^3-m · xH₂O (m≥3) and [Ru^IIICl _m (H₂O) _n ]^3-m (Cl⁻)_3-m · xH₂O (m≤3) type complexes are reduced to the respective – or depending on the electrolyte concentration higher or lower – Ru(II)chloro complexes resulting in mixed valence compounds (phases). Taking into account the layered structure of RuCl₃ the electrochemical reduction can be explained as an intercalation reaction in that mixed valence intercalation phases with a general formula M _x ⁺(H₂O) _y [RuCl₃] ^x− are formed from RuCl₃·x H₂O. The reduction/reoxidation waves are related to the redox transformations of Ru(III) to Ru(II) sites, while the composition of the polynuclear complexes and the structure of microcrystals change. Presented at the 4th Baltic Conference on Electrochemistry, Greifswald, March 13.−16., 2005.     

The Arrangement of First- and Second-shell Water Molecules Around Metal Ions: Effects of Charge and Size

Structural features of clusters involving a metal ion (Li⁺, Na⁺, Be²⁺, Mg²⁺, Zn²⁺, Al³⁺, or Ti⁴⁺) surrounded by a total of 18 water molecules arranged in two or more shells have been studied using density functional theory. Effects of the size and charge of each metal ion on the organization of the surrounding water molecules are compared to those found for a Mg[H₂O]₆²⁺• [H₂O]₁₂ cluster that has the lowest known energy on the Mg²⁺• [H₂O]₁₈ potential energy surface (Markham et al. in J Phys Chem B 106:5118–5134, 2002). The corresponding clusters with Zn²⁺ or Al³⁺ have similar structures. In contrast to this, clusters with a monovalent Li⁺ or Na⁺ ion, or with a very small Be²⁺ ion, differ in their hydrogen-bonding patterns and the coordination number can decrease to four. The tetravalent Ti⁴⁺ ionizes one inner-shell water molecule to a hydroxyl group leaving a Ti⁴⁺(H₂O)₅ (OH⁻) core, and an H₃O⁺• • • H₂O moiety dissociates from the second shell of water molecules. These observations highlight the influence of cation size and charge on the local structure of hydrated ions, the high-charge cations causing chemical changes and the low-charge cations being less efficient in maintaining the local order of water molecules. Electronic Supplementary Material: Supplementary material is available for this article at http://dx.doi.org/10.1007/S00214-005-0056-2.     

Biosorption of metal ions with Penicillium chrysogenum

Biosorption of metal ions with Penicillium chrysogenum mycelium is described in this article. Alkaline pretreatment was used to remove proteins and nucleic acids from cells, and this treatment increased the adsorption capacities, for Cr³⁺ from 18.6 mg g⁻¹ to 27.2 mg g⁻¹, for Ni²⁺ from 13.2 mg g⁻¹ to 19.2 mg g⁻¹, for Zn²⁺ from 6.8 mg g⁻¹ to 24.5 mg g⁻¹. The adsorption of metal ions was strongly pH dependent. The mycelium could beused for large-scale removal of Cr³⁺ from tannery wastewater. The results show that this inexpensive mycelium adsorbent has potential in industry because of its high adsorption capacity. The main chelating sites are amino groups (−NH₂) of chitosan in the mycelium. A new model is established, which describes the relation of adsorption of metal ions on pH according to amino group chelating with metal ions and H⁺. The relative errors of simulation for Cu²⁺, Ni²⁺, Zn²⁺, and Cr³⁺ are 4.66%, 5.45%, 11.55%, and 1.69%, respectively.     

Osmotic and Activity Coefficients of the {<Emphasis Type="Italic">x</Emphasis>ZnCl<Subscript>2</Subscript>+(1−<Emphasis Type="Italic">x</Emphasis>)ZnSO<Subscript>4</Subscript>}(aq) System at 298.15 K

Isopiestic vapor pressure measurements were made for {xZnCl₂+(1−x)ZnSO₄}(aq) solutions with ZnCl₂ molality fractions of x=(0,0.3062,0.5730,0.7969, and 1) at the temperature 298.15 K, using KCl(aq) as the reference standard. These measurements cover the water activity range 0.901–0.919≤a _w≤0.978. The experimental osmotic coefficients were used to evaluate the parameters of an extended ion-interaction (Pitzer) model for these mixed electrolyte solutions. A similar analysis was made of the available activity data for ZnCl₂(aq) at 298.15 K, while assuming the presence of equilibrium amounts of ZnCl⁺(aq) ion-pairs, to derive the ion-interaction parameters for the hypothetical pure binary electrolytes (Zn²⁺,2Cl⁻) and (ZnCl⁺,Cl⁻). These parameters are required for the analysis of the mixture results. Although significant concentrations of higher-order zinc chloride complexes may also be present in these solutions, it was possible to represent the osmotic coefficients accurately by explicitly including only the predominant complex ZnCl⁺(aq) and the completely dissociated ions. The ionic activity coefficients and osmotic coefficients were calculated over the investigated molality range using the evaluated extended Pitzer model parameters.     

Facile preparation and electrochemical properties of large-scale Li<Subscript>1+<Emphasis Type="Italic">x</Emphasis></Subscript>V<Subscript>3</Subscript>O<Subscript>8</Subscript> nanobelts

Large-scale Li_1+x V₃O₈ nanobelts were successfully fabricated using filter paper as deposition substrate through a simple surface sol–gel method. The nanobelts were as long as tens of micrometers with widths of 0.4–1.0 μm and thickness of 50–100 nm. The nanobelts were characterized by X-ray diffration (XRD), Fourier infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM). The formation mechanism of the nanobelts was investigated, showing that the morphology of the nanobelts is mainly determined by the calcination temperature. Electrochemical properties of the Li_1+x V₃O₈ nanobelts were characterized by charge–discharge experiments, and the results demonstrate that the Li_1+x V₃O₈ nanobelts exhibit a high discharge capacity (278 mAh g⁻¹) and excellent cycling stability.     

The influence of polyvinylpyrrolidone on thick and optical properties of BaTiO<Subscript>3</Subscript>:Er<Superscript>3+</Superscript> thin films prepared by sol–gel method

Erbium (Er³⁺) 0.5% mol doped barium titanate (BaTiO₃) thin films were elaborated via sol–gel method and dip-coating technique using titanium alkoxide and barium pentanedionate. Two syntheses were performed [with and without polyvinylpyrrolidone (PVP)] in order to obtain thick films. The BaTiO₃:Er³⁺ thin films prepared from the sol with PVP were elaborated with 1 layer and those without PVP and were elaborated with 17 layers. In both cases, the films were deposited on silica quartz substrates. Both BaTiO₃:Er³⁺ films presented a cubic phase, as determined by X-ray diffraction. BaTiO₃:Er³⁺ films elaborated with PVP via single-step dip coating produced crack-free films with thicknesses of ~800 nm. SEM micrographs for the obtained BaTiO₃:Er³⁺ films revealed high homogeneity and density. Mapping images obtained from BaTiO₃:Er³⁺ revealed homogeneous distribution of Er³⁺ ions on the surface. XPS analyses of the chemical state and chemical environment of the constituent elements in the compositions showed that Er³⁺ ions in (Ba_1−x Er _x )TiO₃ are in mixed valence of Er³⁺/Er²⁺. The BaTiO₃:Er³⁺-PVP film exhibited luminescent properties under near-infrared excitation, as revealed by green emissions. The BaTiO₃:Er³⁺-PVP film has good potential for optical applications.     

Cation mobility in modified Li1 ? xTi2 ? xNbx(PO4)3 lithium titanium NASICON phosphates

Li_{1 − x} Ti_{2 − x} Nb _x (PO₄)₃ NASICON materials are prepared and studied by X-ray diffraction, ⁷Li and ³¹P NMR spectroscopy, and impedance spectroscopy. Vacancy mobility in Li_{1 − x} Ti_{2 − x} Nb _x (PO₄)₃ is lower than interstitial lithium mobility. Nb⁵⁺ cations with low doping levels increase cation mobility in LiTi₂(PO₄)₃. Original Russian Text ? I.Yu. Pinus, I.A. Stenina, A.I. Rebrov, N.A. Zhuravlev, A.B. Yaroslavtsev, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 8, pp. 1240–1244.     

Electrochemical kinetics of nanosized Ag and Ag2O thin films prepared by radio frequency magnetron sputtering

Ag and Ag₂O thin films have been prepared by radio frequency magnetron sputtering on Cu substrates and have been characterized by X-ray diffraction, scanning electron microscope and atomic force microscope. The electrochemical performance of the thin films has been studied by galvanostatic cycling and cyclic voltammetry. The potential dependence of Li-ion chemical diffusion coefficients, [(D)\tilde]_\textLi {\widetilde{D}_{\text{Li}}} , of the films has been determined by galvanostatic intermittent titration technique and electrochemical impedance spectroscopy. It is found that Li-ion chemical diffusion coefficients of the Ag film range from 10⁻¹⁶ to 3 × 10⁻¹⁴ cm² s⁻¹. The Ag/Li₂O composite that is formed from Ag₂O after the first cycle exhibits higher [(D)\tilde]_\textLi {\widetilde{D}_{\text{Li}}} values than the Ag film, especially at a low Li-intercalation content. The phase transitions in the two-phase region cause a significant decrease of chemical diffusion coefficients.     

Oxygen addition effects on electrochromic properties of PECVD-synthesized WO x C y films for flexible electrochromic devices

An investigation was conducted into the electrochromic properties of organotungsten oxide WO _x C _y films synthesized onto 60 Ω/□ flexible polyethylene terephthalate/indium tin oxide substrates using low temperature, plasma-enhanced chemical vapor deposition (PECVD) at varying oxygen concentrations. The PECVD-synthesized WO _x C _y films were proven to offer remarkable electrochromic performance. Cyclic voltammetry switching measurements revealed that only low driving voltages from −1 to 1 V are needed to provide reversible Li⁺ ion intercalation and de-intercalation in a 0.1 M LiClO₄–PC electrolyte. Light modulation with transmittance variation of up to 72.9% and coloration efficiency of 62.5 cm²/C at a wavelength of 650 nm was obtained.     

Potassium-conducting solid electrolytes in K<Subscript>1 − 2<Emphasis Type="Italic">x</Emphasis></Subscript>Sr<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>GaO<Subscript>2</Subscript> system

New solid electrolytes with a high conductivity by K⁺ ions in the K_{1 − 2x} Sr _x GaO₂ system are synthesized and studied. It is found that the introduction of Sr²⁺ ions into potassium monogallate leads to the formation of solid solutions with KGaO₂ structure in a wide range of additive concentration. These solid solutions exhibit a high conductivity; the conductivity increases monotonically with increasing concentration of strontium within the single-phase range. The electrical characteristics are related to the electrolyte structure. The results are compared with the earlier data for the gallate solid electrolytes with the additives of four-charged cations and the systems based on potassium monoferrite and monoaluminate.     

Synthesis of the perovskite ceramic Li3xLa2/3–xTiO3 by a chemical solution route using a triblock copolymer surfactant

The synthesis of the perovskite Li_3xLa_2/3–x□_1/3–2xTiO₃ by a chemical solution route, using a triblock copolymer surfactant, PEO_n–PPO_m–PEO_n, is described. This titanate is a non-hygroscopic fast lithium conductor and therefore is a good candidate for electrochemical applications. It is generally prepared by a conventional solid-state reaction (SSR) method. However this synthesis method does not allow the preparation of nanopowders or the formation of thin films. For these special purposes, synthesis by a chemical solution route, with the formation of a polymeric precursor during synthesis, has been investigated. By using the above-mentioned non-ionic surfactant, the preparation of nanopowders of complex oxides can be done. Furthermore, this way of synthesis leads to the formation of an intermediate polymeric precursor which can be easily spread on substrates to obtain films. We show that the formation of a pure phase of the perovskite Li_3xLa_2/3–x□_1/3–2xTiO₃ is highly dependent on the synthesis conditions, namely the presence of water in the solvent, the EO/metal ratio, the Li⁺ content in the precursor and the calcination temperature. The influence of these parameters on the microstructure of the oxide is studied by X-ray diffraction, scanning electron microscopy and granulometry. A powder of Li_3xLa_2/3–x□_1/3–2xTiO₃ (x = 0.10), with an average particles size of 200 nm, has been obtained. The ionic conductivity of this oxide is the same as the one obtained with oxide prepared by SSR (a bulk conductivity of 1.4 × 10⁻³ S/cm at 37 °C). The ceramic obtained from this powder after sintering at 1,150 °C shows a good pH response. This material can then be used as a sensitive membrane in a potentiometric pH sensor. The presence of hydrophobic PPO groups in the polymer precursor allowed preparing films of Li_3xLa_2/3–x□_1/3–2xTiO₃ with a good adherence on Pt substrate. This kind of synthesis is then very promising to prepare micro pH sensors.