Copper diffusion in solid copper sulfide electrode

Sanchez, Sylvie; Cassaignon, Sophie; Vedel, J.; Meier, H. Gomez

doi:10.1016/0013-4686(95)00454-8

Cited by 18 publications

(21 citation statements)

References 13 publications

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“…It has already been shown in previous studies [16,39,40] that it is possible to determine the chemical diffusion coefficient of copper in copper sulfide, Dcu, from electrochemical impedance spectroscopy (EIS) spectra. According to Wagner Jr. [10] for a non stoichiometric compound the concentration to be considered is the deviation from stoichiometry.…”

Section: Resultsmentioning

confidence: 99%

“…One can quote Rickert [42,43], Tinter [44], Castel [41], Pauporte [45], Sanchez [16] and Allen [38].…”

Section: Data From Literaturementioning

confidence: 99%

“…Copper sulfide has been extensively studied (conductivity [17][18][19], structure [20][21][22][23][24][25][26][27][28][29][30], band structure [13][14][15], phase diagram [25,[31][32][33][34], thermodynamic properties [10-12, 26, 33, 35], electrochemistry [16,36,37]). …”

Section: Introductionmentioning

confidence: 99%

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Copper diffusion in copper sulfide: a systematic study

Cassaignon

Pauporté

Guillemoles

et al. 1998

Ionics

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Abstract.Copper sulfide Cu2_xS is a model mineral for chalcogenides because of the existence of a non-stoichiometric compounds series in the range Cu2S -CuS in which properties change with x. For this reason, we have studied the influence of the mineral composition on the diffusion in this solid.Electrochemical Impedance Spectroscopy (EIS) applied to CU2_xS/cupric sulfate electrolyte was the main investigation technique. It enabled us to work at the equilibrium potential at which the composition is fixed and known. Changing the composition by electrochemically removing (or adding) a known amount of Cu, we were able to determine the chemical diffusion coefficient of copper in the composition range (from x = 0 to 0.066). In this work, we present the results obtained in the chalcocite and djurleite phases. These results were compared to other values reported in the literature. From this systematic study we discuss various diffusion mechanisms. Our observations support that in chalcocite and djurleite Cu diffuses via a vacancy mechanism.

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Section: Resultsmentioning

confidence: 99%

“…One can quote Rickert [42,43], Tinter [44], Castel [41], Pauporte [45], Sanchez [16] and Allen [38].…”

Section: Data From Literaturementioning

confidence: 99%

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Copper diffusion in copper sulfide: a systematic study

Cassaignon

Pauporté

Guillemoles

et al. 1998

Ionics

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“…[30][31][32][33][34][35] It requires considering the kinetic equations of all the steps of the mechanism.…”

Section: -Diffusion Of Watermentioning

confidence: 99%

“…It is equivalent to Warburg impedance 30 and presents the term (jω) −0.5 characteristic of a diffusion. Taking into account of the double layer capacitance (characteristic of the capacitive current [30][31][32][33][34][35][36] ) the global electrical circuit defined for this system is given in Figure 6. The analytical expressions of all the electrical parameters involving in the faradaic impedance are gathered in Table II.…”

Section: R T1 K A1mentioning

confidence: 99%

Kinetic Model of Aluminum Behavior in Cement-Based Matrices Analyzed by Impedance Spectroscopy

Delpech¹,

Cannes²,

Barré³

et al. 2017

J. Electrochem. Soc.

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Aluminum reactivity in cement-based matrices, generally used for conditioning low-and intermediate-level radioactive wastes, is a problem due to dihydrogen produced by the corrosion reaction which depends on the pH of the pore solution. Electrochemical impedance spectroscopy has been used to propose a mechanism for aluminum corrosion in cementitious matrices based on ordinary Portland cement (OPC, pH ≈ 13) or magnesium phosphate cement (MKP, pH ranging between 4 and 9) containing or not LiNO 3 as a corrosion inhibitor. The fit of impedance diagrams recorded on aluminum electrode as a function of time has been realized using electrical parameters to model the cement and kinetic constants for the faradaic impedance. The so determined kinetic constants are used to calculate the corrosion current and the dihydrogen production as a function of time. Comparison of these results with experimental measurements of dihydrogen release obtained by gas chromatography shows a very good agreement except in the MKP matrix containing LiNO 3 . In the OPC matrix, dihydrogen production is between 500 and 1000 times higher than in the MKP matrix, which put in evidence the significant benefit in using MKP cements for aluminum encapsulation. It has long been common practice to stabilize and solidify lowand intermediate-level radioactive wastes using cement before sending them to disposal.1-3 The wastes are confined with a cement or a mortar in a steel container which is closed. Ordinary Portland Cement (OPC) is one of the most widely used materials for conditioning radioactive wastes. Indeed, it is inexpensive, it can be easily supplied and, after hydration, it can exhibit high stability over time. 4 However, wastes produced by nuclear activities are very diverse and, under certain circumstances, can chemically react with cementbased phases or aqueous interstitial solution, thus reducing the quality of the conditioning material. For instance, the dismantling of old nuclear reactors generates a large volume of low and intermediate-level wastes, some of them containing metallic aluminum. Aluminum is a reactive amphoteric metal, forming a protective oxide layer on contact with air or water. This layer is generally stable in the pH range 4-9. [5][6][7] However, in a strongly alkaline medium, such as that encountered in conventional cementitious materials based on OPC, this layer is soluble, resulting in continued corrosion with associated liberation of dihydrogen. Then, the use of Portland cement to encapsulate large amounts of aluminum is prohibited. The formation of dihydrogen contributes to increase the pressure in the container which is able to crack. It is the reason why the main criterion for metallic waste management is based on the volume of dihydrogen production.In this context, our work concerns the aluminum reactivity in cement-based matrices for conditioning radioactive wastes. To overcome the Al corrosion, the strategy proposed consists in (i) replacing OPC by an alternative mortar leading to a pore solution with an appropria...

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Potential of CuS cap to prevent decomposition of Cu₂ZnSnS₄ during annealing

Larsen

Scragg

Frisk

et al. 2015

Physica Status Solidi (a)

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One of the challenges associated with processing of Cu2ZnSnS4 (CZTS) is the thermal decomposition reaction that causes loss of S and SnS from the absorber surface. To reduce the decomposition a sufficiently high SnS and S partial pressure must be supplied during annealing. The absorber surface can alternatively be protected with a thin cap. Aiming to obtain a more flexible process, CZTS precursors were capped with a thin CuS layer before annealing. The cap was subsequently removed with a KCN etch before device finishing. It was found that the cap coverage decreased during annealing, exposing a part of the absorber surface. At the same time, the initially Cu poor absorber took up Cu from the cap, ending up with a stoichiometric Cu content. Devices made from capped precursors or precursors annealed without sulfur had poor device characteristics. An increased doping density of almost one order of magnitude could be the reason for the very poor performance. CuS is therefore not a suitable cap material for CZTS. Other cap materials could be investigated to protect the CZTS absorber surface during annealing. A thin CuS cap is deposited on CZTS to prevent surface decomposition during annealing.

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Copper diffusion in solid copper sulfide electrode

Cited by 18 publications

References 13 publications

Copper diffusion in copper sulfide: a systematic study

Copper diffusion in copper sulfide: a systematic study

Kinetic Model of Aluminum Behavior in Cement-Based Matrices Analyzed by Impedance Spectroscopy

Potential of CuS cap to prevent decomposition of Cu₂ZnSnS₄ during annealing

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Copper diffusion in solid copper sulfide electrode

Cited by 18 publications

References 13 publications

Copper diffusion in copper sulfide: a systematic study

Copper diffusion in copper sulfide: a systematic study

Kinetic Model of Aluminum Behavior in Cement-Based Matrices Analyzed by Impedance Spectroscopy

Potential of CuS cap to prevent decomposition of Cu2ZnSnS4 during annealing

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About

Potential of CuS cap to prevent decomposition of Cu₂ZnSnS₄ during annealing