Intercalation of lithium from Al–Li alloys into lithium titanates

Hardeman, R. W.; Fray, Derek J.

doi:10.1179/mst.1988.4.8.745

Cited by 7 publications

(5 citation statements)

References 6 publications

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“…The intercalation principle was also applied by Fray et al to remove lithium from the aluminum-lithium alloy using pellets of lithium titanate (Li 2ϩx O•TiO 2 ). 33 It is therefore likely that in the experiment represented by Fig. 9a, the reduction current during the first three potential cycles was mainly related to oxygen expulsion from the oxide scale which was then gradually converted to one of the calcium titanates.…”

Section: C6mentioning

confidence: 94%

“…In fact, intercalation of cations of alkali and alkaline earth metals into some solid phases of special structures is well known. 20,[29][30][31][32][33] A good example is the lithium ion battery in which lithium intercalation occurs in both the graphite negative and metal oxide positive electrodes. The intercalation principle was also applied by Fray et al to remove lithium from the aluminum-lithium alloy using pellets of lithium titanate (Li 2ϩx O•TiO 2 ).…”

Section: C6mentioning

confidence: 99%

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Voltammetric Studies of the Oxygen-Titanium Binary System in Molten Calcium Chloride

Chen

Fray

2002

J. Electrochem. Soc.

131

116

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Cyclic voltammetry was applied to study the O-Ti binary system in pre-electrolyzed (2.7-3.0 V) molten CaCl2 at 900°C. Before melting, the salt was thermally dried in air, following a four-stage heating program (60°C/h, 1 h at 90°C, 10°C/h, 4 h at 300°C) to minimize hydrolysis. The O-Ti system was represented by oxide-scale-coated titanium that was prepared by heating commercially pure titanium in air at 700°C. The voltammograms exhibited three reduction processes at electrode potentials more positive than that of the reduction of calcium cation. Two of these, at less negative potentials, could be attributed to the reductions of TiO2 to Ti2O3, and TiO to Ti metal, respectively. The Ti2O3 was found to disproportionate into TiO2 and TiO. The third process occurred at a more negative potential, but still more positive than that of calcium cation reduction, and was proven to be the cathodic ionization of dissolved oxygen from the metal phase. It was also found that for partially reduced oxide scale, various calcium titanates could form under conditions that promote reaction of CaO with, or calcium cation intercalation into, the oxide scale. © 2002 The Electrochemical Society. All rights reserved.

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Section: C6mentioning

confidence: 94%

Section: C6mentioning

confidence: 99%

Voltammetric Studies of the Oxygen-Titanium Binary System in Molten Calcium Chloride

Chen

Fray

2002

J. Electrochem. Soc.

131

116

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“…In fact, intercalation of cations of alkali and alkaline earth metals into some solid phases of special structures is well known. 48 In the lithium ion battery, e.g., the intercalation of lithium occurs into either the graphite negative or metal oxide positive electrodes. The intercalation principle was also applied successfully by Fray et al to intercalate lithium from the molten Al-Li alloys into lithium titanate for the molten aluminum purification.…”

Section: Rationalization Of the Ca Features Of A Canbmentioning

confidence: 99%

“…The intercalation principle was also applied successfully by Fray et al to intercalate lithium from the molten Al-Li alloys into lithium titanate for the molten aluminum purification. 23,48 49 When the insulating Nb 2 O 5 was intercalated with calcium, it became electronically conductive. The formation of the calcium-intercalated Nb 2 O 5 allowed the cathodic oxygen ionization to proceed at the oxide-electrolyte interface rather than at the threephase boundaries as required for the oxygen ionization of pure Nb 2 O 5 .…”

Section: Rationalization Of the Ca Features Of A Canbmentioning

confidence: 99%

Electrochemical Studies on Reduction of Solid Nb[sub 2]O[sub 5] in Molten CaCl[sub 2]-NaCl Eutectic

Xiao¹,

Fray²

2005

J. Electrochem. Soc.

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Cathodic processes during the electrodeoxidation of solid Nb 2 O 5 in thermally dried and pre-electrolyzed molten CaCl 2 -NaCl eutectic were studied at temperatures 850-950°C using cyclic voltammetry and chronoamperometry, respectively. In cyclic voltammograms at 850-950°C, several reduction peaks were clearly observed at the potentials at least 0.8 V vs ͑Na + , Ca 2+ ͒/͑Na-Ca͒ less cathodic than those of the metals deposition from the eutectic melt, confirming the concept of cathodic oxygen ionization. The chronoamperometric studies showed that the cathodic processes at the potentials of 0.7-0.2 V vs ͑Na + , Ca 2+ ͒/͑Na-Ca͒ always started with the oxygen ionization of the CaNb 2 O 6 film on the surface of the Nb 2 O 5 electrode in the molten CaCl 2 -NaCl eutectic electrolyte, which was governed by the oxygen diffusion within the film toward the CaNb 2 O 6 -electrolyte interface. The subsequent oxygen ionization of the oxides at the surface took place consecutively and/or simultaneously. Surface characterizations of the Nb 2 O 5 electrodes before and after the chronoamperometric measurements revealed that there existed a marked dependence of the morphologies, compositions, and phases on the imposed potential steps and that the calcium cations were intercalated electrochemically into the Nb 2 O 5 structure at the surface at relatively less cathodic potentials than that of the sodium deposition from the molten CaCl 2 -NaCl eutectic.

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“…These compounds have been used to remove impurities from molten metals by simply setting up a circuit between the intercalating compound, lithium titanate and the metal through a molten salt electrolyte. 27 Alkali metals and other elements have been removed from molten aluminium. 28 It has been known for decades that alkali atoms can intercalate into graphite, but recently it was found that by setting up a cell where graphite cathode is placed in a bath of a molten halide that it is possible, by forcing the alkali atoms into the graphite that carbon nanotubes and other nanoparticles could be formed.…”

Section: Intercalation From Molten Saltsmentioning

confidence: 99%

Innovative electrochemical processing using molten salts

Fray¹

2006

Mineral Processing and Extractive Metallurgy

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Until recently, the only electrochemical applications using molten salts involved the direct electrolysis or electrorefining using molten salts in which the ion carrying the current was predominant in the molten electrolyte. In recent years, there has been a considerable amount of research into high temperature fuel cells and batteries and some of this technology is directly applicable to the molten salts processing of materials. Combining molten salts with solid electrolytes has led to novel processes for the preparation of sodium, magnesium and other metals. It is known that the alkaline earth chlorides dissolve substantial quantities of their own oxides, leading to electrolytes that are oxygen ion conductors, under certain conditions, and these electrolytes have been used to remove oxygen from oxide cathodes to give pure metals. Surprisingly, it has been found that when the cathodes consist of mixtures of alloys, the product is an alloy or intermetallic compound. This approach may offer a more cost effective way of preparing high value added materials. Intercalation of alkali and alkaline earth elements into oxides and graphite is discussed. The former could be used for the refining of metals and the latter for the preparation of carbon nanotubes.

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Intercalation of lithium from Al–Li alloys into lithium titanates

Cited by 7 publications

References 6 publications

Voltammetric Studies of the Oxygen-Titanium Binary System in Molten Calcium Chloride

Voltammetric Studies of the Oxygen-Titanium Binary System in Molten Calcium Chloride

Electrochemical Studies on Reduction of Solid Nb[sub 2]O[sub 5] in Molten CaCl[sub 2]-NaCl Eutectic

Innovative electrochemical processing using molten salts

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