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We describe the synthesis, crystal structure and lithium deinsertion–insertion electrochemistry of two new lithium-rich layered oxides, Li3MRuO5 (M = Mn, Fe), related to rock salt based Li2MnO3 and LiCoO2. The Li3MnRuO5 oxide adopts a structure related to Li2MnO3 (C2/m) where Li and (Li0.2Mn0.4Ru0.4) layers alternate along the c-axis, while the Li3FeRuO5 oxide adopts a near-perfect LiCoO2 (R3̅m) structure where Li and (Li0.2Fe0.4Ru0.4) layers are stacked alternately. Magnetic measurements indicate for Li3MnRuO5 the presence of Mn3+ and low spin configuration for Ru4+ where the itinerant electrons occupy a π*-band. The onset of a net maximum in the χ vs. T plot at 9.5 K and the negative value of the Weiss constant (ϑ) of −31.4 K indicate the presence of antiferromagnetic superexchange interactions according to different pathways. Lithium electrochemistry shows a similar behaviour for both oxides and related to the typical behaviour of Li-rich layered oxides where participation of oxide ions in the electrochemical processes is usually found. A long first charge process with capacities of 240 mA h g−1 (2.3 Li per f.u.) and 144 mA h g−1 (1.38 Li per f.u.) is observed for Li3MnRuO5 and Li3FeRuO5, respectively. An initial sloping region (OCV to ca. 4.1 V) is followed by a long plateau (ca. 4.3 V). Further discharge–charge cycling points to partial reversibility (ca. 160 mA h g−1 and 45 mA h g−1 for Mn and Fe, respectively). Nevertheless, just after a few cycles, cell failure is observed. X-ray photoelectron spectroscopy (XPS) characterisation of both pristine and electrochemically oxidized Li3MRuO5 reveals that in the Li3MnRuO5 oxide, Mn3+ and Ru4+ are partially oxidized to Mn4+ and Ru5+ in the sloping region at low voltage, while in the long plateau, O2− is also oxidized. Oxygen release likely occurs which may be the cause for failure of cells upon cycling. Interestingly, some other Li-rich layered oxides have been reported to cycle acceptably even with the participation of the O2− ligand in the reversible redox processes. In the Li3FeRuO5 oxide, the oxidation process appears to affect only Ru (4+ to 5+ in the sloping region) and O2− (plateau) while Fe seems to retain its 3+ state. [ABSTRACT FROM AUTHOR]

Aliovalent substitution of Nb5+ by Ti4+ in Sr2LuNbO6 is limited to 10% of Nb atoms. A full structural determination by NPD confirms this and reveals that the structure is better described as a superstructure of the simple cubic perovskite (as previously reported) with the monoclinic cell 21/2ap × 21/2ap × ²ap and ß ≈ 90° (S.G. P21/n). The substituted materials present both oxygen-vacancies induced by charge compensation and Sr-deficiency. Therefore, their formula should be given as Sr2-yLuNb1-xTixO6-δ. Electrical properties can be fully understood considering these compositional defects. The parent compound Sr2LuNbO6 presents low electrical conductivity in air, which improves by more than one order of magnitude upon Ti substitution. In any case, the title oxides show low electrical conductivity in a wide oxygen partial pressure (pO2) range (10-25 atm = pO2 = 10-1 atm). At high pO2 the conductivity increases with pO2 due to oxygen-vacancy annihilation and hole creation, according to a general p-type semiconducting mechanism; A-site substoichiometry and Tisubstitution are the origin of this behaviour. In the low pO2 region, the conductivity increases as the oxygen partial pressure decreases. Reduction of cations, Nb5+ or Ti4+, supports n-type conduction by electrons and oxygen vacancy creation. For the intermediate pO2 range a low ionic conduction contribution is observed. Although the estimated ionic conductivity is not high in the substituted compounds, the strategy seems to be valid since a significant enhancement of ionic conduction is observed upon aliovalent substitution. [ABSTRACT FROM AUTHOR]

The structural features of intercalated Li3AlxTi2−x(PO4)3 compounds, with x = 0 and 0.2, have been deduced by Rietveld analysis of neutron diffraction (ND) patterns recorded between 100 and 500 K. The Li insertion decreases the symmetry from R3̅c to R3̅ in analyzed compounds. In pristine Li1+xAlxTi2−x(PO4)3 samples, Li occupies mainly six-fold M1 sites at ternary axes; but in lithiated Li3AlxTi2−x(PO4)3 samples, Li is located near M2 positions at M3/M3′ four-fold coordinated sites. In both cases, Li arrangement minimizes electrostatic Li–Li repulsions. The insertion of lithium resulted in the reduction of Ti4+ to Ti3+ that shifts 7Li, 27Al and 31P MAS-NMR resonances towards more positive chemical shifts, improving the resolution of different sites. The detection of twelve components in 7Li MAS-NMR spectra recorded at room temperature suggests the location of Li+ ions at three-oxygen faces that define M2 cavities. From 7Li MAS-NMR spectra, the occupancy of sites and mobility of lithium were investigated in the temperature range 100–500 K. The correlation between structural information, deduced by neutron diffraction, and lithium mobility, deduced by NMR spectroscopy, provides new insights into structural factors that affect lithium mobility in materials with NASICON structure. [ABSTRACT FROM AUTHOR]

The development of sustainable, safe, low-cost, high energy and density power-density energy storage devices is most needed to electrify our modern needs to reach a carbon-neutral society by ~2050. Batteries are the backbones of future sustainable energy sources for both stationary off-grid and mobile plug-in electric vehicle applications. Biomass-derived carbon materials are extensively researched as efficient and sustainable electrode/anode candidates for lithium/sodium-ion chemistries due to their well-developed tailored textures (closed pores and defects) and large microcrystalline interlayer spacing and therefore opens-up their potential applications in sustainable potassium and aluminum batteries. The main purpose of this perspective is to brief the use of biomass residues for the preparation of carbon electrodes for potassium and aluminum batteries annexed to the biomass-derived carbon physicochemical structures and their aligned electrochemical properties. In addition, we presented an outlook as well as some challenges faced in this promising area of research. We believe that this review enlightens the readers with useful insights and a reasonable understanding of issues and challenges faced in the preparation, physicochemical properties and application of biomass-derived carbon materials as anodes and cathode candidates for potassium and aluminum batteries, respectively. In addition, this review can further help material scientists to seek out novel electrode materials from different types of biomasses, which opens up new avenues in the fabrication/development of next-generation sustainable and high-energy density batteries.

The present work elucidates facile one-pot synthesis from biomass forestry waste (Norway spruce bark) and its chemical activation yielding high specific surface area ( S BET ) biochars as efficient lithium- and sodium-ion storage anodes. The chemically activated biochar using ZnCl 2 (Biochar-1) produced a highly mesoporous carbon containing 96.1% mesopores in its structure as compared to only 56.1% mesoporosity from KOH-activated biochars (Biochar-2). The latter exhibited a lower degree of graphitization with disordered and defective carbon structures, while the former presented more formation of ordered graphite sheets in its structure as analyzed from Raman spectra. In addition, both biochars presented a high degree of functionalities on their surfaces but Biochar-1 presented a pyridinic-nitrogen group, which helps improve its electrochemical response. When tested electrochemically, Biochar-1 showed an excellent rate capability and the longest capacity retentions of 370 mA h g -1 at 100 mA g -1 (100 cycles), 332.4 mA h g -1 at 500 mA g -1 (1000 cycles), and 319 mA h g -1 at 1000 mA g -1 after 5000 cycles, rendering as an alternative biomass anode for lithium-ion batteries (LIBs). Moreover, as a negative electrode in sodium-ion batteries, Biochar-1 delivered discharge capacities of 147.7 mA h g -1 at 50 mA g -1 (140 cycles) and 126 mA h g -1 at 100 mA g -1 after 440 cycles., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Aims: The pharmacokinetic (PK) similarity between MB02, a proposed bevacizumab biosimilar, and reference bevacizumab approved from the USA (US-bevacizumab) and European Union (EU-bevacizumab) was evaluated. Safety and immunogenicity were also assessed., Methods: In this phase 1, randomized, double blind, single dose, parallel group study, 114 healthy male volunteers were randomized 1:1:1 to receive a 3 mg/kg intravenous dose of MB02, US-bevacizumab or EU-bevacizumab, and evaluated for 100 days. PK similarity between MB02 and reference bevacizumab was determined using the standard bioequivalence criteria (0.80-1.25) for the area under the serum concentration-time curve from time 0 extrapolated to infinity (AUC (0-∞) ) and the maximum observed serum concentration (C max )., Results: Baseline demographics were similar across treatment groups. All study drugs exhibited similar PK profile. The 90% confidence interval for the geometric lead square means ratios for the primary parameters AUC (0-∞) and C max for MB02, US-bevacizumab and EU-bevacizumab were fully contained within the pre-defined bioequivalence limits for the 3 pairwise comparisons: AUC (0-∞) (MB02:US-bevacizumab 0.998 [0.944 to 1.05]; MB02:EU-bevacizumab 1.07 [1.00 to 1.14]; and US-bevacizumab:EU-bevacizumab 0.934 [0.884 to 0.988]) and C max (MB02:US-bevacizumab 0.983 [0.897 to 1.08]; MB02:EU-bevacizumab 1.06 [0.976 to 1.16]; and; US-bevacizumab: EU-bevacizumab 0.926 [0.851 to 1.01]). Treatment emergent adverse events were reported in 87 subjects (76.3%), most being mild and with comparable incidence among treatment groups. Thirty-three subjects (28.9%) reported 56 possibly related treatment emergent adverse events with comparable incidence across treatments, the most frequent being headache (10.5%) and fatigue (3.5%). Anti-drug antibody incidence was low and similar between treatment groups., Conclusions: This study demonstrates the PK similarity and bioequivalence of MB02 to the reference bevacizumab, whether approved from USA or EU. The safety and immunogenicity profile of MB02 was shown also to be similar to the bevacizumab reference product (NCT04238663)., (© 2021 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

The electrode performance and degradation of 1:1 La 2-x NiTiO 6- δ :YSZ composites (x = 0, 0.2) has been investigated to evaluate their potential use as SOFC cathode materials by combining electrochemical impedance spectroscopy in symmetrical cell configuration under ambient air at 1173 K, XRD, electron microscopy and image processing studies. The polarisation resistance values increase notably, i.e., 0.035 and 0.058 Ωcm 2 h -1 for x = 0 and 0.2 samples, respectively, after 300 h under these demanding conditions. Comparing the XRD patterns of the initial samples and after long-term exposure to high temperature, the perovskite structure is retained, although La 2 Zr 2 O 7 and NiO appear as secondary phases accompanied by peak broadening, suggesting amorphization or reduction of the crystalline domains. SEM and TEM studies confirm the ex-solution of NiO with time in both phases and also prove these phases are prone to disorder. From these results, degradation in La 2-x NiTiO 6- δ :YSZ electrodes is due to the formation of La 2 Zr 2 O 7 at the electrode-electrolyte interface and the ex-solution of NiO, which in turn results in the progressive structural amorphization of La 18 NiTiO 6- δ phases. Both secondary phases constitute a non-conductive physical barrier that would hinder the ionic diffusion at the La 2-x NiTiO 6- δ :YSZ interface and oxygen access to surface active area.

The organic solvents that are widely used as electrolytes in lithium ion batteries present safety challenges due to their volatile and flammable nature. The replacement of liquid organic electrolytes by non-volatile and intrinsically safe ceramic solid electrolytes is an effective approach to address the safety issue. However, the high total resistance (bulk and grain boundary) of such compounds, especially at low temperatures, makes those solid electrolyte systems unpractical for many applications where high power and low temperature performance are required. The addition of small quantities of a polymer is an efficient and low cost approach to reduce the grain boundary resistance of inorganic solid electrolytes. Therefore, in this work, we study the ionic conductivity of different composites based on non-sintered lithium lanthanum titanium oxide (La 0.5 Li 0.5 TiO 3 ) as inorganic ceramic material and organic polymers with different characteristics, added in low percentage (<15 wt.%). The proposed cheap composite solid electrolytes double the ionic conductivity of the less cost-effective sintered La 0.5 Li 0.5 TiO 3 .

The structure of β-Na 0.33 V 2 O 4.67 F 0.33 has been investigated by both theoretical and experimental methods. It exhibits the same structure as that of the parent bronze β-Na 0.33 V 2 O 5 . The partial substitution of oxygen by fluorine has little effect on the average structure and cell parameters, but the sodium environment changes significantly. Using DFT calculations, we determined the most stable positions of fluorine atoms in the unit cell. It was found that the partial replacement of oxide by fluoride takes mainly place in the coordination sphere of Na producing a shortening of the Na-anion bond lengths. We also analyzed the electronic properties based on density of states and Bader charge distribution. The crystallochemical situation of sodium ions in β-Na 0.33 V 2 O 4.67 F 0.33 oxyfluoride, detected by both experimental and computational methods, affects its mobility with respect to the parent oxide. The higher ionicity in the Na coordination sphere of β-Na 0.33 V 2 O 4.67 F 0.33 is related to a sodium ion diffusion coefficient, D Na+ , that is 1 order of magnitude lower (1.24 × 10 -13 cm 2 s -1 ) than in the case of β-Na 0.33 V 2 O 5 (1.13 × 10 -12 cm 2 s -1 ). Electrochemical sodium insertion/deinsertion properties of the oxyfluoride have been also investigated and are compared to the oxide. Insertion/deinsertion equilibrium potential for the same formal oxidation state of vanadium increases due to fluorination (for instance reduction of V +4.3 occurs at 1.5 V in the oxide and at 1.75 V in the oxyfluoride). However, the capacity of Na 0.33 V 2 F 4.67 F 0.33 at constant current is lower than in the case of β-Na 0.33 V 2 O 5 , and a lower oxidation state of vanadium owing to the aliovalent O/F substitution.D Na+ , and a lower oxidation state of vanadium owing to the aliovalent O/F substitution.

Metal oxyfluorides are currently attracting much attention for next-generation rechargeable batteries because of their high theoretical capacity and resulting high energy density. Rhombohedral VO 2 F is promising because it allows two-electron transfer during electrochemical lithium cycling, with a theoretical capacity of 526 mAh g -1 . However, the chemical changes it undergoes during operation are not clearly understood. In this work, a combination of synchrotron X-ray and neutron diffraction was employed to accurately describe the crystal structure of both pristine and lithiated VO 2 F, using samples with high crystallinity to overcome challenges in previous studies. The mechanism and reversibility of the lithium insertion was monitored in real time by high angular synchrotron diffraction measurements, performed in operando on a lithium battery in the high-voltage range: 3.9-2.3 V vs Li + /Li. Insertion of up to one lithium ion proceeds through a solid-solution reaction, while Rietveld refinements of neutron powder diffraction data revealed that the lithiated states adopt the noncentrosymmetric R 3 c framework, uncovering an octahedral Li-(O/F) 6 coordination with reasonable Li-O/F bond lengths. This work further evaluates the redox changes of VO 2 F upon Li intercalation. By a comparison of changes in electronic states of all the elements in the compound, it clarifies the critical role of both anions, O and F, in the charge compensation through their covalent interactions with the 3d states of V. The clear evidence of participation of F challenges existing assumptions that its high electronegativity renders this anion largely a spectator in the redox reaction.

The partial substitution of up to 5% Nd+3 by Ca+2 results in the oxide Nd1.90Ca0.10MgTiO5.94 that presents some remarkable structural features with a noticeable influence on its properties. In this oxide with a monoclinic perovskite-like structure and an octahedral tilting scheme (a-a-b+), both A- and B-ions are arranged in a rock-salt like manner, representing therefore the first example of a type of perovskite theoretically predicted. Besides this unprecedented arrangement of A- and B-ions, the oxygen vacancies created through doping with acceptor ions are trapped by association with the acceptor defects and hence the mobility of these vacancies is strongly limited. The oxygen conductivity of the substituted material is lower and the activation energy for oxygen motion is higher than those of the parent oxide, in which the concentration of anion vacancies is only due to intrinsic defects.

Materials with the formula Sr 2 CoNb 1-x Ti x O 6-δ (x=1.00, 0.70; δ=number of oxygen vacancies) present a cubic perovskite-like structure. They are easily and reversibly reduced in N 2 or Ar and re-oxidized in air upon heating. Oxidation by water (wet N 2 ), involving splitting of water at a temperature as low as 700 °C, produces hydrogen. Both compounds displayed outstanding H 2 production in the first thermochemical cycle, the Sr 2 CoNb 0.30 Ti 0.70 O 6-δ material retaining its outstanding performance upon cycling, whereas the hydrogen yield of the x=1 oxide showed a continuous decay. The retention of the materials' ability to promote water splitting correlated with their structural, chemical, and redox reversibility upon cycling. On reduction/oxidation, Co ions reversibly changed their oxidation state to compensate the release/recovery of oxygen in both compounds. However, in Sr 2 CoTiO 6-δ , two phases with different oxygen contents segregated, whereas in Sr 2 CoNb 0.30 Ti 0.70 O 6-δ this effect was not evident. Therefore, this latter material displayed a hydrogen production as high as 410 μmol H 2  g -1 perovskite after eight thermochemical cycles at 700 °C, which is among the highest ever reported, making this perovskite a promising candidate for thermosolar water splitting in real devices., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In the frame of a repositioning programme with cholinergic medicines in clinical use searching for neuroprotective properties, we surprisingly found that spasmolytic antimuscarinics otilonium and pinaverium exhibited neurotoxic effects in neuronal cultures. We decided to characterize such unexpected action in primary cultures of rat embryo cortical neurons. Neurotoxicity was time- and concentration-dependent, exhibiting approximate EC 50 values of 5 μM for both drugs. Seven antimuscarinic drugs endowed with a quaternary ammonium, and another 10 drugs with different cholinergic activities, carrying in their molecule a ternary ammonium did not exhibit neurotoxicity. Both drugs caused a concentration-dependent blockade of whole-cell inward currents through voltage-activated calcium channels (VACCs). Consistent with this, they also blocked the K + -elicited [Ca 2+ ] c transients. Neither antioxidant catalase, glutathione, n-acetylcysteine, nor melatonin protected against neurotoxicity of otilonium or pinaverium. However cyclosporine A, a blocker of the mitochondrial permeability transition pore, prevented the neurotoxic effects of otilonium and pinaverium monitored as the fraction of cells undergoing apoptosis. Furthermore, the caspase-9 and caspase-3 inhibitor Ac-LEHD-CHO mitigated the apoptotic neuronal death of both drugs by around 50%. Data are compatible with the hypothesis that otilonium and pinaverium elicit neuronal death by activating the intrinsic mitochondrial-mediated signaling pathway of apoptosis. This may have its origin in the mitigation of Ca 2+ entry and the uncoupling of the Ca 2+ -dependent generation of mitochondrial bioenergetics, thus causing the opening of the mitochondrial mPTP to elicit apoptotic neuronal death., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Previous studies have found an association between the SNP rs143383 + 104T/C in the growth differentiation factor 5 (GDF5) gene and the risk of developing knee osteoarthritis (KOA) in various populations worldwide., Objective: To discover if there is an association between the SNP rs143383 + 104T/C, in the GDF5 gene and the risk of developing KOA in individuals from northern Mexico., Methods: We used a case-control study format that included 145 patients with KOA and 145 healthy controls unrelated to patients. A peripheral blood sample was taken for each of them to identify the SNP by means of real-time PCR according to standard protocols., Results: We found a strong association between the TT genotype and the risk of developing KOA (OR = 1.7, 95% CI = 1.12-2.8, p = 0.014), but not in the heterozygous TC state (OR = 1.56, CI 95% = 0.58-4.17, p = 0.367)., Conclusion: The TT genotype of the SNP rs143383 increases the susceptibility to KOA in the population of northern Mexico, according to the recessive segregation model.

The perovskite series Sr 2 CoNb 1-x Ti x O 6-δ (0≤x≤1) was investigated in the full compositional range to assess its potential as cathode material for solid oxide fuel cell (SOFC). The variation of transport properties and thus, the area specific resistances (ASR) are explained by a detailed investigation of the defect chemistry. Increasing the titanium content from x=0-1 produces both oxidation of Co 3+ to Co 4+ (from 0 up to 40 %) and oxygen vacancies (from 6.0 to 5.7 oxygen atom/formula unit), although each charge compensation mechanism predominates in different compositional ranges. Neutron diffraction reveals that samples with high Ti-contents lose a significant amount of oxygen upon heating above 600 K. Oxygen is partially recovered upon cooling as the oxygen release and uptake show noticeably different kinetics. The complex defect chemistry of these compounds, together with the compositional changes upon heating/cooling cycles and atmospheres, produce a complicated behavior of electrical conductivity. Cathodes containing Sr 2 CoTiO 6-δ display low ASR values, 0,13 Ω cm 2 at 973 K, comparable to those of the best compounds reported so far, being a very promising cathode material for SOFC., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Compound IG20 is a newly synthesised sulphated glycolipid that promotes neuritic outgrowth and myelinisation, at the time it causes the inhibition of glial proliferation and facilitates exocytosis in chromaffin cells. Here we have shown that IG20 at 0.3-10 μM afforded neuroprotection in rat hippocampal slices stressed with veratridine, glutamate or with oxygen plus glucose deprivation followed by reoxygenation (OGD/reox). Excess production of reactive oxygen species (ROS) elicited by glutamate or ODG/reox was prevented by IG20 that also restored the depressed tissue levels of GSH and ATP in hippocampal slices subjected to OGD/reox. Furthermore, the augmented iNOS expression produced upon OGD/reox exposure was also counteracted by IG20. Additionally, the IG20 elicited neuroprotection was prevented by the presence of inhibitors of the signalling pathways Jak2/STAT3, MEK/ERK1/2, and PI3K/Akt, consistent with the ability of the compound to increase the phosphorylation of Jak2, ERK1/2, and Akt. Thus, the activation of phase II response and the Nrf2/ARE pathway could explain the antioxidant and anti-inflammatory effects and the ensuing neuroprotective actions of IG20., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The symmetry of the room-temperature (RT) structure of title compounds La 2-x Sr x CoTiO 6-δ changes with x, from P2 1 /n (0 ≤ x ≤ 0.2) to Pnma (0.3 ≤ x ≤ 0.5) and to R3̅c (0.6 ≤ x ≤ 1). For x = 1 the three pseudocubic cell parameters become very close suggesting a transition to a cubic structure for higher Sr contents. Similar phase transitions were expected to occur on heating, paralleling the effect of internal pressure induced by substitution of La 3+ by Sr 2+ . However, only some of these aforementioned transitions have been thermally induced. The symmetry-adapted modes formalism is used in the structural refinements and fitting of neutron diffraction data recorded from RT to 1273 K. Thus, for x = 1, the out-of-phase tilting of the BO 6 octahedra vanishes progressively on heating, and a cubic structure with Pm3̅m symmetry is found at 1073 K. For lower Sr contents this transition is predicted to occur far above the temperature limit of common experimental setups. The analysis of the evolution of the perovskite tolerance factor, t-factor, with both Sr content and temperature indicates that temperature has a limited ability to release structural stress and thus to enable transitions to more symmetric phases. This is particularly true when compared to the effect of internal pressure induced by substitution of La by Sr. The existence of phase transitions in materials for solid oxide fuel cells that are usually exposed to heating-cooling cycles may have a detrimental effect. This work suggests strategies to stabilize the high-symmetry high-temperature phase of perovskite oxides through internal-pressure chemically induced.

Titanium-oxide-based materials are considered attractive and safe alternatives to carbonaceous anodes in Li-ion batteries. In particular, the ramsdellite form TiO2 (R) is known for its superior lithium-storage ability as the bulk material when compared with other titanates. In this work, we prepared V-doped lithium titanate ramsdellites with the formula Li0.5 Ti1-x Vx O2 (0≤x≤0.5) by a conventional solid-state reaction. The lithium-free Ti1-x Vx O2 compounds, in which the ramsdellite framework remains virtually unaltered, are easily obtained by a simple aqueous oxidation/ion-extraction process. Neutron powder diffraction is used to locate the Li channel site in Li0.5 Ti1-x Vx O2 compounds and to follow the lithium extraction by difference-Fourier maps. Previously delithiated Ti1-x Vx O2 ramsdellites are able to insert up to 0.8 Li(+) per transition-metal atom. The initial gravimetric capacities of 270 mAh g(-1) with good cycle stability under constant current discharge conditions are among the highest reported for bulk TiO2 -related intercalation compounds for the threshold of one e(-) per formula unit., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new hydrated sodium nickel fluoride with nominal composition NaNiF3·3H2O was synthesized using an aqueous solution route. Its structure was solved by means of ab initio methods from powder X-ray diffraction and neutron diffraction data. NaNiF3·3H2O crystallizes in the cubic crystal system, space group Pn3̅ with a = 7.91968(4) Å. The framework, derived from the ReO3 structure type, is built from NaX6 and NiX6 (X = O, F) corner-shared octahedra, in which F and O atoms are randomly distributed on a single anion site. The 2a × 2a × 2a superstructure arises from the strict alternate three-dimensional linking of NaX6 and NiX6 octahedra together with the simultaneous tilts of the octahedra from the cube axis (φ = 31.1°), with a significant participation of hydrogen bonding. NaNiF3·3H2O corresponds to a fully cation-ordered variant of the In(OH)3 structure, easily recognizable when formulated as NaNi(XH)6 (X = O, F). It constitutes one of the rare examples for the a(+)a(+)a(+) tilting scheme with 1:1 cation ordering in perovskite-related compounds. The Curie-like magnetic behavior well-reflects the isolated paramagnetic Ni(2+) centers without worth mentioning interactions. While X-ray and neutron diffraction data evidence Na/Ni order in combination with O/F disorder as a main feature of this fluoride, results from Raman and magic-angle spinning NMR spectroscopies support the existence of specific anion arrangements in isolated square windows identified in structural refinements. In particular, formation of water molecules derives from unfavorable FH bond formation.

We report the rich magnetic behaviour of Sr2CoNb1-xTixO6 (0 ≤ x ≤ 0.5) oxides as a result of their complex microstructure. Although these oxides show an average simple-cubic perovskite structure, they present a flexible microstructure due to short-range ordering between Co/Ti and Nb cations in the perovskite B-sites. The microstructure consists of double-cubic perovskite domains grown in a simple-cubic perovskite matrix. The size and number of the double-cubic perovskite domains decrease as the Ti content increases. As a result of aliovalent substitution of Nb(5+) by Ti(4+) in the parent Sr2CoNbO6 mixed-valence Co(3+)/Co(4+) oxides are obtained. A spin glass-like state has been observed at low temperatures for all the series, with freezing temperatures increasing with the Ti-content in the range 22 to 33 K. Furthermore, the x = 0.3 and x = 0.5 samples show non-interacting superparamagnetic particle-like dynamics associated with relatively high amounts of Co(4+), with "blocking temperatures" of 13 and ∼16 K, respectively. The complex magnetic behaviour of the title oxides seems to be connected with the clustering of magnetic Co(3+) and the distribution of Co(4+) as a result of the microstructure.

Aliovalent substitution of Nb(5+) by Ti(4+) in Sr2LuNbO6 is limited to 10% of Nb atoms. A full structural determination by NPD confirms this and reveals that the structure is better described as a superstructure of the simple cubic perovskite (as previously reported) with the monoclinic cell 2(1/2)ap× 2(1/2)ap× 2ap and β≈ 90° (S.G. P21/n). The substituted materials present both oxygen-vacancies induced by charge compensation and Sr-deficiency. Therefore, their formula should be given as Sr2-yLuNb1-xTixO6-δ. Electrical properties can be fully understood considering these compositional defects. The parent compound Sr2LuNbO6 presents low electrical conductivity in air, which improves by more than one order of magnitude upon Ti substitution. In any case, the title oxides show low electrical conductivity in a wide oxygen partial pressure (pO2) range (10(-25) atm ≤pO2≤ 10(-1) atm). At high pO2 the conductivity increases with pO2 due to oxygen-vacancy annihilation and hole creation, according to a general p-type semiconducting mechanism; A-site substoichiometry and Ti-substitution are the origin of this behaviour. In the low pO2 region, the conductivity increases as the oxygen partial pressure decreases. Reduction of cations, Nb(5+) or Ti(4+), supports n-type conduction by electrons and oxygen vacancy creation. For the intermediate pO2 range a low ionic conduction contribution is observed. Although the estimated ionic conductivity is not high in the substituted compounds, the strategy seems to be valid since a significant enhancement of ionic conduction is observed upon aliovalent substitution.

The structural features of intercalated Li3AlxTi2-x(PO4)3 compounds, with x = 0 and 0.2, have been deduced by Rietveld analysis of neutron diffraction (ND) patterns recorded between 100 and 500 K. The Li insertion decreases the symmetry from R3̄c to R3̄ in analyzed compounds. In pristine Li1+xAlxTi2-x(PO4)3 samples, Li occupies mainly six-fold M1 sites at ternary axes; but in lithiated Li3AlxTi2-x(PO4)3 samples, Li is located near M2 positions at M3/M3' four-fold coordinated sites. In both cases, Li arrangement minimizes electrostatic Li-Li repulsions. The insertion of lithium resulted in the reduction of Ti(4+) to Ti(3+) that shifts (7)Li, (27)Al and (31)P MAS-NMR resonances towards more positive chemical shifts, improving the resolution of different sites. The detection of twelve components in (7)Li MAS-NMR spectra recorded at room temperature suggests the location of Li(+) ions at three-oxygen faces that define M2 cavities. From (7)Li MAS-NMR spectra, the occupancy of sites and mobility of lithium were investigated in the temperature range 100-500 K. The correlation between structural information, deduced by neutron diffraction, and lithium mobility, deduced by NMR spectroscopy, provides new insights into structural factors that affect lithium mobility in materials with NASICON structure.