On the substitution of lithium in copper oxide
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.
Abstract: The extent of solubility of Li + in monoclinic CuO and its effect on the crystal structure and electrical behaviour have been studied employing different experimental techniques. It is found that (i) the extent of lithium incorporation in CuO is limited to ≤ 25at%, (ii) the defect compounds, Cu 1−x Li x O 1− δ , are formed without altering the crystal structure and (iii) the resistivity decreases with increase in Li concentration. Further, it is observed that these compounds continue to exhibit semiconducting ( d ϱ dT ) behaviour.
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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.
455 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
Cites background from "On the substitution of lithium in c..."
...Es wurde eine Löslichkeit von 2 mol% [159] bis 4-6 mol% gefunden [149, 160], während eine Löslichkeit von bis zu 25 mol% [161] zweifelhaft ist....
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442 citations
TL;DR: In this article, the properties of the system Li+xNi++1−2xNi+++xO for the entire range 0.3 < x < 0.5 are reported.
Abstract: Crystallographic and magnetic measurements of the system Li+xNi++1−2xNi+++xO for the entire range 0 ⩽ x ⩽ 0.5 are reported. For values ofx ⩽ 0.3, the lattice appears to be antiferro-magnetic and is cubic above the Curie temperature. For the range of compositions 0.3 < x < 0.5, the lattice is rhombohedral and ferrimagnetic, a maximum magnetic moment pet gram of 31 c.g.s. cm3g being observed at x = 0.46. A maximum ferrimagnetic Curie temperature of 241°K was observed for the composition x = 0.41. These properties are interpreted in terms of a partial ordering of lithium and nickel ions into alternate sets of (111) planes which couple antiparallel to one another, the moments within any set being either ferromagnetically coupled or paramagnetic, depending upon the number of non-magnetic near neighbors in the neighboring planes. This system is compared to the ordered rock-salt-type compound Cu0.25Co0.75O. The lack of ferrimagnetism and the tetragonal distortion to c/a < 1 in Cu0.25Co0.75O are explained.
213 citations
TL;DR: The resistivity of nonmetallic La/sub 2-sub y/Sr/sub y,Cu/sub 1-//sub x/Li/sub X/O/sub 4-sub delta/ single crystals and ceramics accurately follows the functional form exp((T/sub 0/T)/sup 1/4/), characteristic of variable-range hopping as mentioned in this paper.
Abstract: The resistivity of nonmetallic La/sub 2-//sub y/Sr/sub y/Cu/sub 1-//sub x/Li/sub x/O/sub 4-//sub delta/ single crystals and ceramics accurately follows the functional form exp((T/sub 0//T)/sup 1/4/), characteristic of variable-range hopping. For each of the crystals grown from Li-containing flux and CuO flux, pure reduced ceramics, and ceramics containing 0.025 to 0.2 mol % Li, the values of T/sub 0/ are in the range 0.3--7 x 10/sup 6/ K. The hopping conductivity shows that the crystals, which also manifest the two-dimensional quantum spin fluid state, antiferromagnetism, and the tetragonal-to-orthorhombic transition, are nonmetallic because the electronic states at the Fermi energy are localized. No evidence of a large gap is observed, and all samples, including the reduced ceramic, are p type, leading to the suggestion that in the nonmetallic state as well as the superconductor, the Fermi energy lies near the top of the band of singly occupied states (lower Hubbard band). The suppression of superconductivity by Li impurities is discussed.
124 citations
TL;DR: In this paper, the symmetry requirements of the monoclinic system were shown to be satisfied by Story-Iaskelyne's drawings of melaconite with cuprite and chrysocolla.
Abstract: The goniometrical measurements of N. Story-l\\laskelyne ) on crystals of tenorite (also called melaconite) found with cuprite and chrysocolla in a chloritic veinstone from Lostwithiel, Cornwall, satisfy the symmetry requirements of the monoclinic system, and the crystal habit illustrated in the drawing of Story-l\\1askelyne is clearly that of the holohedral class of the monoclinic system. ~Ioreover, as A. Scacchi) has pointed out, the goniometrical measurements of J. J enzsch ) on artificial crystals of cupric oxide formed near a flue in a smelterhearth during roasting of copper matte with sodium chloride at Freiberg, yield calculated elements agreeing with those of Story-1\\Iaskelyne, and the crystals drawn by J enzsch exhibited the same habit and twinlaw as those of Story-·Maskelyne. J enzsch interpretE
66 citations
TL;DR: In this paper, the influence of four dopant lithium concentrations on the electrical properties of CuO was investigated, showing an initial strong decrease of the conduction activation energies for small contents of Li (<1.7 at. %), which becomes weak for larger contents.
Abstract: We present an investigation of the influence of four dopant lithium concentrations on the electrical properties of CuO. X-ray measurements have revealed a single phase formed up to 4.2 at. % of Li, and a second phase formed, Li2CuO2, in the case of 10.5 at. % of Li concentration. The log(ρ/T) vs 1/T data are better represented by two straight lines than by one and show an initial strong decrease of the conduction activation energies for small contents of Li (<1.7 at. %), which becomes weak for larger contents. The change in slope observed in the resistivity measurements as a function of temperature has also been investigated by calorimetric measurements, revealing a specific heat anomaly which can be associated with the antiferromagnetic order transition.
63 citations