Phase transformations in La2-xYxMo2O9 (x = 0.05, x = 0.075): Temperature cycling and DRT analysis

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Formation and characteristics of thin films of ZrO2-8 mol % Y2O3 solid electrolytes

[6th International Conference on Self-Formation Theory and Applications Vilnius, Lithuania, Nov. 26-28, 2003]Thin films of ZrO2-8mol % Y2O3 have been deposed by pulsed DC magnetron sputtering method. The substrates of Ni-cermet and alloy-600 for the films were used. The results of the investigation of the X-ray diffraction patterns and SEM showed that the films are nanocrystalline and belong to cubic symmetry. The relaxation process is related to the ion transport in thin films. The results of the investigation of the temperature dependencies of thin films ionic conductivity showed that the dependence (T) is caused by the temperature dependence of oxygen vacancy mobility, while the number of charge carriers remains constant with temperatureLietuvos energetikos institutas, [email protected] universitetasVilniaus universitetas, [email protected] universitetas, [email protected] Didžiojo universiteta

Zr2-8 mol.% Y2O3 plonųjų sluoksnių gamybos technologija ir jų elektrinės savybės

Pateiktos ZrO2-8 mol.% Y2O3 plonųjų sluoksnių gamybos technologinės sąlygos, naudojant impulsinį magnetroną, o taip pat aprašyti sluoksnių joninio laidumo sando temperatūriniai ir dažniniai tyrimai. Elektriniai matavimai atlikti 300-1000 K temperatūrų intervale ir 2 10(4)-10(6) Hz dažnių diapazone. Plonųjų sluoksnių nusodinimas vyko 0,25-1,8 Pa slėgio O2 dujose. Sluoksniai buvo formuojami ant lydinio 600 bei 5 sv.% CSY/95 sv.% NiO padėklų. Kintamajame 2 10(4)-10(6) Hz dažnių elektriniame lauke aptikta relaksacinė elektrinių parametrų dispersija, kuri siejama su VO-- pernaša plonuosiuose sluoksniuose. Parodyta, kad temperatūrinį kristalitinio laidžio kitimą daugiausia lemia VO- krūvininkų judrio temperatūrinis kitimasThin films of ZrO2-8 mol.% Y2O3 have been deposed by pulsed magnetron sputtering on Ni-cermet and alloy-600 substrates. Investigation of the X-ray diffraction patterns and SEM has shown that the films are polycrystalline and belong to cubic symmetry. The relaxation process is related to the ion transport in thin films. Investigation of the temperature dependences of thin film ionic conductivity [sigma] has shown that the dependence [sigma](T) is caused by the temperature dependence of oxygen vacancy mobilityLietuvos energetikos institutas, [email protected] universitetasVytauto Didžiojo universiteta

Electrochemical performance of highly conductive nanocrystallized glassy alluaudite-type cathode materials for NIBs

Alluaudite-type materials are systematically attracting more attention as prospective cathode materials for sodium-ion batteries. It has been demonstrated that optimized thermal nanocrystallization of glassy analogs of various cathode materials may lead to a significant increase in their electrical conductivity. In this paper, three alluaudite-like glasses (Na2Fe3(PO4)3—FFF, Na2VFe2(PO4)3—VFF, and Na2VFeMn(PO4)3—VFM) were synthesized and subjected to an optimized thermal nanocrystallization. This procedure resulted in nanostructured samples with increased electrical conductivity at room temperature: 5×10−7 S/cm (FFF), 7×10−5 S/cm (VFM), and 6×10−4 S/cm (VFF). The nanocrystalline microstructure was also evidenced by ultra-high-frequency impedance spectroscopy (up to 10 GHz) and proposed electrical equivalent circuits. Prototype electrochemical cells were assembled and characterized with voltage cutoffs of 1.5 and 4.5 V. The electrochemical performance was, however, modest. The gravimetric capacity varied between the studied materials, but did not exceed 35 mAh/g. Capacity retention after ca. 100 cycles was satisfactory. Further optimization of the residual-glass-to-nanocrystallite volume ratio would be desirable

Electrochemical Performance of Highly Conductive Nanocrystallized Glassy Alluaudite-Type Cathode Materials for NIBs

Alluaudite-type materials are systematically attracting more attention as prospective cathode materials for sodium-ion batteries. It has been demonstrated that optimized thermal nanocrystallization of glassy analogs of various cathode materials may lead to a significant increase in their electrical conductivity. In this paper, three alluaudite-like glasses (Na2Fe3(PO4)3—FFF, Na2VFe2(PO4)3—VFF, and Na2VFeMn(PO4)3—VFM) were synthesized and subjected to an optimized thermal nanocrystallization. This procedure resulted in nanostructured samples with increased electrical conductivity at room temperature: 5×10−7 S/cm (FFF), 7×10−5 S/cm (VFM), and 6×10−4 S/cm (VFF). The nanocrystalline microstructure was also evidenced by ultra-high-frequency impedance spectroscopy (up to 10 GHz) and proposed electrical equivalent circuits. Prototype electrochemical cells were assembled and characterized with voltage cutoffs of 1.5 and 4.5 V. The electrochemical performance was, however, modest. The gravimetric capacity varied between the studied materials, but did not exceed 35 mAh/g. Capacity retention after ca. 100 cycles was satisfactory. Further optimization of the residual-glass-to-nanocrystallite volume ratio would be desirable

Anomalous temperature-dependent electrical properties of Na 2 MnP 2 O 7

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