Copper Ion Conductor Research Articles

Two new quaternary copper bismuth sulfide halides: CuBi2S3Cl and CuBi2S3Br as candidates for copper ion conductivity

Two new quaternary copper bismuth sulfide halides: CuBi2S3Cl and CuBi2S3Br as candidates for copper ion conductivity

High-Temperature Corrosion of Copper Induced by TeO2

It was found that copper is susceptible to the accelerated high-temperature corrosion induced by TeO2 at 650°C in air, which occurs at a constant rate. The calculated corrosion rate constant is 4.5 × 10−4 kg·m−2·s−1 and does not depend on the specific mass of tellurium oxide. Based on the results of the analysis of the microstructure (scanning electron microscopy/energy dispersive x-ray spectroscopy) and the phase composition (x-ray diffraction) of two formed corrosion layers, the phase distribution in the corrosion product has been ascertained. It was shown that during the corrosion process at 650°С, the inner corrosion layer containing Cu2O and Cu2Te and the outer corrosion layer mainly containing CuTe2O5 and Cu2O were formed. The inner layer provides a high copper ion conductivity due to Cu2Te, while the outer layer possesses a high oxygen ion conductivity due to the oxide melt. The mechanism of the overall corrosion process has been proposed.

Order–disorder phenomena in layered CuCrSe2 crystals

The thermal motion of Cu+ ions in a quasi-two dimensional copper ion conductor CuCrSe2 is studied in the vicinity of the order-disorder phase transition to superionic phase, basing on a single-crystal and powder X-ray diffraction, specific heat and electrical resistivity measurements. The copper ions gradually migrate with temperature decrease to empty tetrahedral sites reaching occupancy equilibrium in the disordered high-temperature phase at Ts = 365 K. The copper migration between Cuα and Cuβ tetrahedral sites occurs through the neighboring, face-sharing octahedral holes. Disorder of Cu+ ions brings perturbations in periodic potential of the crystal lattice providing additional scattering centers for electrons.

Structure-property relationships of fast copper ion conductor cubic CuI

Structure-property relationships of fast copper ion conductor cubic γ-CuI (300 K) and α-CuI (773 K) has been investigated using the time-of-flight (TOF) neutro powder diffraction over the Q-range up to 30 Å − 1 . Crystal structure of the both γ- and α-phases were refined using the conventional Rietveld methods combined with the maximum-entropy-method (MEM), whilst the local structures were analyzed by means of the pair distribution function (PDF) combined with the reverse Monte Carlo (RMC) simulation. The crystal structure analysis revealed temperature dependence of large thermal displacement of copper ions along <111> directions, with average copper ions density mostly distributed at the 8 c center of tetrahedrally-coordinated by I ions. The PDF analysis estimated the new peak position of Cu–Cu pairs shifted from 4.27 Å in the γ-phase to 2.49 Å in the α-phase and estimation of coordination number decreases from 12.1 to 5.8, respectively. The local structure analysis found the new split peaks of g Cu–Cu( r) at r about 2.47 Å and 2.72 Å in the α-phase that roughly correspond to the Cu–Cu diagonally distance between nearest neighboring tetrahedral corner 32 f-32 f sites and between tetrahedral center 8 c-32 f sites such as represented by the splitting Cu site model of Fm-3m.

A study of copper stoichiometry and phase relationships in the copper-zirconium phosphate system: CuZr2(PO4)3 – Cu0.5Zr2(PO4)3

CuZr2(PO4)3 crystallises with the Nasicon-type structure and is a copper(I) ion conductor. The possibility of a solid solution between CuZr2(PO4)3 and Cu0.5Zr2(PO4)3 has been a controversial issue for many years. As part of a continued study, CuZr2(PO4)3 and Cu0.5Zr2(PO4)3 were prepared by solid state methods and used to investigate the copper stoichiometry and phase relationships between these two materials as a function of copper content, temperature and oxygen fugacity. The following reversible reaction: Cu0.5Zr2(PO4)3 (s) + \(\frac{1}{2}\)CuO (s) ↔ CuZr2(PO4)3 (s) + \(\frac{1}{4}\)O2(g) was studied by thermogravimetry in an atmosphere of PO2 = 0.22 atm and was found to occur at 475 ± 10°C. Thus, CuZr2(PO4)3 is a thermodynamically stable phase in air above ∼475°C, which places a lower temperature limit on its use as an electrolyte in air. The results of X-ray powder diffractometry on materials with various copper contents that had been annealed in argon at 750°C indicate that there is no evidence for a significant solid solution between CuZr2(PO4)3 and Cu0.5Zr2(PO4)3 nor, a reductive decomposition of Cu0.5Zr2(PO4)3. The coexistence of CuZr2(PO4)3 and Cu0.5Zr2(PO4)3 as discrete phases is also supported by evidence from electron spin resonance spectroscopy on these materials, which indicate the presence of copper(II) ions in CuZr2(PO4)3 at a dopant and dispersed level of concentration. The results from energy dispersive X-ray analysis, as well as, the novel use of the fluorescent behaviour of CuZr2(PO4)3 in ultra-violet light as an analytical tool, support the above conclusions.

The use of copper(I) halides as a preparative tool

The use of copper(I) halides as a preparative tool is discussed with respect to the synthesis of adduct compounds with new polymeric and oligomeric main group molecules. By using this approach new polymers of main group elements--some of which have been predicted by theoretical investigations--can be obtained in a crystalline state and are therefore accessible for a basic structural characterization. Thus, it becomes possible to compare the structural data, experimental data, and theoretical results. Mixed copper halide chalcogenides are accessible when complex copper thiometalates and copper halides are combined. These solid-state compounds are of special interest since they provide experimental access to new main group molecules. In addition, they exhibit a high copper ion conductivity when certain structural features are present in the compounds. A survey is given of basic synthetic and general structural aspects.

Ionic Conductor Composites: Theory and Materials

The main theoretical concepts on ionic conduction at interfaces, especially the space charge layer model, are summarized in the first part of this review: ion trapping or redistribution leads to charge carrier accumulation, depletion or inversion and, consequently, to conductivity changes in composite materials. Experimental confirmations of the space charge layer model and the complementary percolation model are discussed. Major developments of ionic conductor composite materials over the last 25 years are presented in the second part, including lithium and other alkaline ion conductors, copper and silver ion conductors, di- and trivalent cation and anion conductors, glass and polymer composites. Some future trends and research needs are indicated in conclusion.

Composite Copper Chalcogenide Halides: Neutron Powder Diffraction of CuClCu2TeS3 and Electrical Properties of CuClCu2TeS3, (CuI)2Cu3SbS3, and (CuI)3Cu2TeS3

The crystal structure of CuClCu2TeS3 was refined from TOF neutron powder diffraction data in order to verify the distribution of chlorine and sulfur. It is a novel derivative of the zincblende type with an ordered distribution both of the cations Cu+ and Te4+ and of the anions Cl− and S2−. The compound crystallizes in the rhombohedral system, space group R3m (No. 160) with a=7.3502(1) Å, c=10.3873(2) Å, V=485.99 Å3, and Z=3. The structure refinement converged to Rwp=0.039 and RBragg=0.032. From the neutron data it can be derived that there is no significant disorder of Cl and S atoms. Impedance spectroscopic measurements in the temperature range 140–280°C reveal that CuClCu2TeS3 is a semiconductor with an activation energy of 0.75 eV (T<200°C) and 1.25 eV (T>200°C), respectively. On the other hand (CuI)3Cu2TeS3 and (CuI)2Cu3SbS3 exhibit high copper ion conductivity with activation energies of 0.2 and 0.35 eV, respectively, but a negligible electronic conduction.

Copper(I) halide-phosphorus adducts: a new family of copper(I) ion conductors

Ion exchange experiments and impedance spectroscopy investigations were performed on adducts of copper(I) halides to phosphorus and polyphosphorchalcogenide polymers, respectively. All compounds under investigation except one showed an ion exchange reaction ( Cu + → Ag +) in an aqueous silver nitrate solution at room temperature and are therefore considered to contain mobile copper ions. Impedance measurements on (CuI) 8P 12, (CuI) 3P 12 and Cu 3P 15I 2 demonstrated that the total conductivity of (CuI) 8P 12 and (CuI) 3P 12 is predominantly ionic with corresponding activation energies of 0.45 and 0.59 eV, respectively, while the conductivity of Cu 3P 15I 2 is mainly electronic with a related activation energy of about 0.72 eV.

Phase transition and copper ion conductor in PbBr2-CuBr

The solid solution of PbBr2-CuBr has a high electric conductivity above 150 °C. The frequency and temperature dependences of complex dielectric constants have been investigated in the concentration of x=0.01-0.3. They exhibited a strong dieletric relaxation caused by the ionic conduction. Specific heat capacities have been measured in the temperature range from 100 to 200 °C. They showed no anomalous specific heat at the temperature 150 °C, but a distinct peak of heat was found at about 170 °C depending on the concentration. Using the simplified model of disorder of mobile ions, the excess specific heat was explained as the transition of copper ions between two sites.

New Copper Phosphates as Ionic or Mixed Conductors

AbstractAs part of a search for solid‐state copper ion conductors, new copper phosphate compounds of the Nasicon or alluaudite type structure were synthesized. Compounds with the former structure are reported here in more depth. CuTiZrP3O12 and the previously prepared compound CuTi2P3O12 were found to be copper ion conductors with a relatively low electronic contribution, and comparable both in structure and in conductivity behaviour to both CuZr2P3O12 and the NaZr2P3O12 end‐member of the classical Nasicon composition range. In contrast to the Cu(I) halide conductors these phases are stable under ambient conditions. Partial substitution of Zr by Sc, or Ti by Cr (rather than Si for P) results in a new Cu‐rich compound Cu2ZrScP3O12, together with the previously prepared compound Cu2TiCrP3O12, both showing expectedly very high Cu+ conductivity comparable to Nasicon compounds with a similar charge carrier concentration. A new related phase CuTiCrP3O12 was also synthesized. Magnetic measurements, Wagner‐Hebb polarization and e.m.f. measurements performed to elucidate partial conductivity contributions and valence states are discussed. The e.m.f. results obtained with Cu‐activity cells reveal a predominant ionic conductance together with a minor but not negligible electronic contribution resulting in a fast copper diffusion. Cu–Fe and Cu–Mg phosphates were also prepared for the first time as first examples of quaternary compounds in the Cu–Fe–P–O and Cu–Mg–P–O system respectively. These materials, Cu1,3Fe3P3O12 and Cu2Mg3P3O12 were found to be of the alluaudite structure type, with predominant electronic conductivity at high temperature.

Some performance characteristics of a solid-state battery composed of Chevrel phase, a copper-ion conductor, and Prussian blue

A solid-state battery composed of copper molybdenum sulphide (Chevrel phase: CP), copperion conductive solid electrolyte, and iron hexacyanoferrate complex (Prussian blue: PB), was studied from the viewpoint of its applicability to a recyclable energy source. The electromotive force increased with the copper content of the CP. The discharge capacity increased with increasing sulphur content as well as copper content of the CP. The discharge-charge cycling behaviour indicated that both CP and PB containing a three-dimensional open structure were potential electrode materials for a promising rechargeable battery.

Low-energy excitation in CuI

Neutron inelastic scattering of the copper-ion conductor CuI is measured bythe time-of-flight (TOF) method at 35, 200, 280 and 360°C. The neutron inelastic spectra are analyzed by the use of a model function for the generalized density of states. This model function consists of two components: a low-energy excitation mode and phonon modes due to the transverse acoustic branch. The value of the dispersionless low-energy excitation ℏω∼3.4 meV is almost independent of temperature. The relation between the excitation energy and the mass of the cations can be represented by ℏω∼( 1 M ) 1 2 . The relation could also be described as a cation plasma model with an appropriate effective charge of the cation.

A study of the mass transport properties of the solid state copper(I) ion conductor Rb 4Cu 16I 7Cl 13 and its application in the determination of the thermodynamic stability of Nd 2CuO 4

The preparation of Rb 4 Cu 16 I 7 Cl 13 from the respective metal halides in flowing argon is described. The electrochemical behavior of the solid state cell Cu|Rb 4 Cu 16 I 7 Cl 13 |Cu has been studied by impedance spectroscopy. The electronic resistance of the external circuit is significant and is taken into consideration in the evaluation of the ionic conductivity. Rb 4 Cu 16 I 7 Cl 13 has a copper ion conductivity of 69 Sm −1 at 473 K, and an activation energy of 14 kJ mole −1 in the temperature range 351 to 473 K. Titration of copper through the cell revealed interesting morphological features of copper crystal growth at 473 K. EMF measurements on the cell Cu|Rb 4 Cu 16 I 7 Cl 13 |Nd 2 CuO 4 , Nd 2 O 3 , O 2 , Pt gave δ G o =−27,300 −61 T J mole −1 K −1 for the cell reaction Cu(c)+0.5 O 2 (g)+Nd 2 O 3 (c)=Nd 2 CuO 4 (c).

Electrochemical properties of copper-based polymer electrolytes

Consistent interest has lately been devoted to complexes formed between poly(ethylene oxide), PEO, and multivalent metal salts, since these polymer electrolytes offer challenging prospects for investigation, both in terms of definition of bulk transport properties of complicated, multiphase systems and in terms of the evaluation of practical application in advanced electrochemical devices, such as flat, thin-layer batteries and laminated electrochromic windows. In this work we present results obtained by complex impedance spectroscopy, cyclic voltammetry and differential scanning calorimetry on a series of PEOCU(CF 3SO 3) 2 complexes prepared using different techniques. The data suggest that these complexes are copper ion conductors, although the overall transport mechanism is still unclear.

Some performance characteristics of a solid-state battery composed of Chevrel phase, a copper-ion conductor, and Prussian blue

Some performance characteristics of a solid-state battery composed of Chevrel phase, a copper-ion conductor, and Prussian blue

Limiting-current chlorine gas sensor based on β″-alumina solid electrolyte

A new type of limiting-current solid-state ionic gas sensor for gases that may not be transferred in solid electrolytes is presented. The sensor is based on the reaction of the gaseous species with the electroactive component under the condition of limited access of the gas by a kinetic barrier. The technique allows the presently available fast solid alkali metal, silver and copper ion conductors to be used at ambient and moderately increased temperatures. A linear relationship between the electrical current and the gas concentration is observed for chlorine gas. The device may be operated at lower temperatures than the potentiometric chlorine gas sensor, is sensitive to low partial gas pressures and may also overcome problems of cross-sensitivity. Sensors for gases other than chlorine may be based on the same principle.

Rechargeability of solid-state copper cells utilizing cathodes of Prussian blue and Berlin green

Discharge and cycling performance of solid-state cells using copper metal, copper ion conductor, and iron hexacyanoferrates, Prussian blue (PB) and Berlin green (BG), was studied. The discharge capacities from start (0.58 V) to 0.4 V of the Cu/PB and Cu/BG cells at 100 μA/cell were 1.35 and 1.98 mAh respectively. At this time, cathode efficiencies were 62% for PB and 79% for BG. The Cu/BG cell showed nearly flat discharge- and charge-end voltage curves over 700 cycles, while the Cu/PB cell displayed the very slowly decreasing curves. The cell performance was discussed on the basis of the crystal structure for ionic diffusion and the hopping mechanism through high- and low-spin iron ions for electronic conduction in the cathode materials.

A study of the mass transport properties of the solid-state copper(I) ion conductor CuZr2P3O12 and its limitations in the determination of the thermodynamic stability of Nd2CuO4

The preparation of CuZr 2 P 3 O 12 from NH 4 H 2 PO 4 , Cu 2 O and ZrO 2 is described. The electrochemical behaviour of the solid state cell Pt/CuZr 2 P 3 O 12 /Pt was studied by impedance spectroscopy. For the first time copper was titrated through the solid state cell Cu/CuZr 2 P 3 O 12 /Au at 1073 K, demonstrating that CuZr 2 P 3 O 12 is a copper(I) ion conductor. CuZr 2 P 3 O 12 has a copper ion conductivity of 3.4 S m −1 at 1073 K, and an activation energy of 0.42 eV for the temperature range 673–1273 K. CuZr 2 P 3 O 12 is unstable with respect to oxidation, therefore electrochemical measurements are restricted to non-oxidizing environments which limits its practical use. An attempt was made, given these constraints, to determine the free energy of formation of Nd 2 CuO 4 .

Analysis of solid state battery resistances

Solid state batteries are fabricated to study their internal resistance in thin film and pellet forms, using two different electrolytes with the following configurations: type 1 is Pb/PbCl 2: n MCl/AgCl/Ag, where n = 1, 3 or 5 mol.%. M = K or Rb, and type 2 is Cu/Rb 4Cu 16I 7Cl 13/V 2O 5 or Se. The electrical resistance of the electrolyte itself is measured by a normal a.c. impedance bridge (using gold electrodes) and is compared with the cell resistances measured by the loading method (R.N. Prasad, N.M. Abhyankar, R.N. Karekar, T.S. Rao and S.D. Phadke, Thin Solid Films, 161 (1988) 77; R.N. Prasad, N.M. Abhyankar, S.D. Phadke and R.N. Karekar, Thin Solid Films, 164 (1988) 345) and also by the V OC/ I SC method. The total internal resistance R in may be divided into various parts: R mig (resistance associated with migration), R dis (resistance associated with dissociation), R diff (resistance associated with diffusion), R re (resistance associated with reaction) and R el (electronic shunt resistance). The dominant governs the current of the cell, depending on the cell constituents. For all the cells R in changes with R L in a non-linear way. The possibility of space-charge-limited current phenomena is checked by plotting R in vs. 1/ I L 1 2 , which is found to be nearly linear for a copper ion conductor (type 2). These results indicate the dominant contributions to the resistance in the current flow.