Author
Udupa
Bio: Udupa is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Crystal structure & Solid solution. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.
Topics: Crystal structure, Solid solution, Alkali metal, Copper oxide, Lithium
Papers
More filters
TL;DR: In this article, the extent of solubility of Li + in monoclinic CuO and its effect on the crystal structure and electrical behavior have been studied employing different experimental techniques.
4 citations
Cited by
More filters
TL;DR: In this article, the electrochemical reactivity of tailor-made CuO powders prepared according to a new low-temperature synthesis method was studied by a combination of transmission electron microscopy (TEM) and electrochemical techniques.
Abstract: The electrochemical reactivity of tailor-made CuO powders prepared according to a new low-temperature synthesis method was studied by a combination of transmission electron microscopy (TEM) and electrochemical techniques. All the processes involved during cycling were successfully identified. We show that the reduction mechanism of CuO by lithium involves the formation of a solid solution of Cu II 1x Cu I x O 1 1/2 :, 0 ≤ x ≤ 0.4, a phase transition into Cu 2 O, then the formation of Cu nanograins dispersed into a lithia matrix ( Li 2 O) followed by the growth of an organic-type coating. This one is responsible for the extra capacity observed on the voltage vs. composition curve. During the subsequent charge, the organic layer vanishes first, and then the Cu grains are partially or fully oxidized with a concomitant decomposition of Li 2 O. The formation of Li 2 O and Cu nanograins and then the one of Cu. CuO, and Cu 2 O nanograins on the first discharge and subsequent charge, respectively, were identified by high-resolution TEM studies. These results enabled a better understanding of the processes governing the reactivity of 3d metal oxides vs. lithium down to 0.02 V.
469 citations
TL;DR: LiCu 2 O 2 crystals were studied by powder X-ray diffraction and phase analysis showed that the applied growth conditions are suitable for preparation of a single-phase compound.
Abstract: LiCu 2 O 2 crystals grown by spontaneous crystallization from the fluxed melt were studied by powder X-ray diffraction. The phase analysis shows that the applied growth conditions are suitable for preparation of a single-phase compound. The as-grown crystals contain only traces of foreign phases (Li 2 CuO 2 , CuO, Cu 2 O) typical for preparation of the LiCu 2 O 2 compound. Attempts to anneal or quench the as-grown crystals led to two-phase samples containing LiCu 2 O 2 and LiCu 3 O 3 . X-ray powder diffraction pattern of a LiCu 2 O 2 crystal is reported and compared with literature data. The crystal structure is orthorhombic, space group Pnma , in agreement with literature data. Lattice parameters of the studied sample are a =5.7286(2) A, b =2.8588(1) A, and c =12.4143(3) A. Time evolution of a diffraction pattern illustrates a slow increase of the secondary-phases contribution assumed to be due to interaction of the powdered crystal with humid air. A brief summary of compounds known in the Li–Cu–O system is included
9 citations
TL;DR: In this paper, thin thin films were prepared by plasma-enhanced chemical vapor deposition (CVD) with Cu(acac)2 and Inacac3 precursors, and a dependence of the resistivity of the films on the indium concentration was found.
Abstract: CuO:In thin films were prepared by plasma-enhanced chemical vapor deposition (CVD) with Cu(acac)2 and In(acac)3 precursors. A unique method or facility in vaporizing solid-state precursors and the transportation to the CVD reactor was described. The structure of the films evolved from nano-crystalline characteristic to amorphous state as the In/Cu atomic ratio of the mixed precursors increased from 0 to 0.25. A dependence of the resistivity of the films on the indium concentration was found. A low room-temperature resistivity of 7.35 Ω·cm was achieved for the sample of an In/Cu atomic ratio of 0.08, with an activation energy of 0.14 eV. X-ray photoelectron spectroscopy (XPS) study excluded the possibility that the increased conductivity of the samples came from a reduction of Cu2+ to Cu+. Positive holes (h•) induced by negatively charged defect complex were assumed to contribute to the increase of conductivity.
5 citations
15 Dec 2016
TL;DR: In this article, a thermodynamic approach was used to elucidate the electrochemical behavior of conversion-type electrodes using Li-Cu-O and Li-Fe-O as model material systems.
Abstract: Konversionselektroden sind vielversprechende Elektrodenmaterialien fur zukunftige Lithium-Ionen-Batterien, da sie sehr hohe spezifische Kapazitaten im Vergleich zu Interkalationselektroden aufweisen. In dieser Arbeit wird ein thermodynamischer Ansatz gewahlt, um den elektrochemischen Prozess von Konversions-Elektroden anhand der Modell-Systeme Li-Cu-O und Li-Fe-O zu beleuchten. Mit den konsistenten thermodynamischen Beschreibungen konnen elektrochemische Eigenschaften berechnet werden. Conversion-type electrodes are promising electrode materials for future lithium ion batteries since they exhibit high specific capacities compared to intercalation-type eclectrodes. In this work, a thermodynamic approach was used to elucidate the electrochemical behavior of conversion-type electrodes using Li-Cu-O and Li-Fe-O as model material systems. electrochemical properties can be calculated using self-sonstistent thermodynamic descriptions developed in this work. Umfang: XVI, 291 S. Preis: €48.00 | £44.00 | $84.00
5 citations