Copper Ion Conductor Research Articles

Low-energy excitation in copper ion conductors

Neutron inelastic scattering of copper ion conductors Cu 1.8S, Cu 1.8Se and CuI was measured by the time-of-flight (TOF) method at room temperature. Low-lying excitations near ħω≃3.4 meV, which had been observed in the measurement in Cu 2Se, existed in these copper ion conductors. A relation between the excitation energy and the mass of cations can be represented by h ̵ ω≃ 1 M .

Rechargeable solid electrolyte cells employing vanadium-tungsten complex oxide cathodes

Rechargeable solid electrolyte cells have been developed by using a high copper ion conductor, Rb 4Cu 16I 7Cl 13, a copper anode, and vanadium-tungsten complex oxides with Wadsley-Roth phases, V 1+ x W 1− x O 5 (0< x<0.8) and V 2+ x W 3− x O 13 (0< x<1.4). On the basis of convenient polarization measurements, the V 1+ x W 1− x O 5 system was found to be better cathode than the V 2+ x W 3− x O 13 system. The cell with the complex oxide, V 1.30 W 0.70 O 5, showed good charge-discharge performance of cycle numbers more than 500 at a current of 20 μA and the temperature of 25°C. From the viewpoint of the crystallographic open structure, the electronic conduction, and the thermodynamic property, the complex oxides were indicated to be possible cathode materials for rechargeable solid electrolyte cells.

Rechargeable Solid Electrolyte Cells with Copper Ion Conductor and Vanadium-Tungsten Complex Oxide

Rechargeable Solid Electrolyte Cells with Copper Ion Conductor and Vanadium-Tungsten Complex Oxide

Some Battery Applications of Solid Electrolytes in Japan

AbstractIn Japan, some micro-batteries using solid electrolytes, such as silver ion, copper ion and lithium ion conductors are now under development for applying them to micro-devices, integrated-circuits and very-large-scaleintegration. For these purposes, inorganic crystalline and glassy electrolytes as well as polymeric electrolytes have been developed. For electric energy storage batteries, sodium ion conductors such as beta- or beta"- alumina have been developed as the electrolyte. A 1 MW sodium-sulfur battery demonstration power plant is to be constructed in Japan by the fall of 1991. To the fuel cell applications, oxide ion conductors or hydrogen ion conductors have chiefly been tried to be used, though solid electrolyte fuel cells are now at an early stage of development in Japan. Further, an AMTEC system for thermal energy to electrical energy conversion using beta•- alumina is under development in Japan. In this review paper, these battery applications of solid electrolytes in Japan are described briefly.

Characterization of poly(ethylene oxide) copper salt polymer electrolytes

The physico-chemical and electrochemical properties of a new class of polymer electrolytes formed by complexes of poly(ethylene oxide) and copper trifluorosulphonate salts have been investigated. The results suggest that these electrolytes are good copper ion conductors. Under particular conditions of concentration and temperature, and apparent electronic transport has also been evidenced.

Low-Energy Excitation in β-Cu2Se

Neutron inelastic scattering of solid electrolyte β-Cu 2 Se was measured by the time-of-flight (TOF) method at room temperature. Low-lying dispersionless excitations near \(\hbar\omega\sim 3.4\) meV, which would be common to copper ion conductors, existed in the β-phase. This result was compared with those of the excitations in other solid electrolytes.

MnO2 for Solid Electrolyte Cells

Two kinds of manganese dioxide, CMD and EMD, were investigated as the cathode active material for the solid electrolyte cells where is the copper (I) ion conductor and is graphite. The CMD was distributed in the cathode mixture more uniformly than the EMD, and the former gave the cells much better performance than the latter. The EMD subjected to thermal treatment showed that for the cathode material the crystalline powder was superior to the amorphous powder, and that the γ phase was better than the β phase. The discharge reaction of the manganese dioxide cathode was explained by the mechanism similar to that in dry cells.

Effect of Halides on Fast Copper-Ion Conductor in Phosphate-Based Glasses

Total electrical conductivity depends on both the content of cuprous ions and of the halide ions in the glass.Considerably large electronic conductivity of the glasses suggests that hopping conduction between Cu+ and Cu2+ is likely to occur. Contribution of the halide ions to the electrical conductivity can be explained that they drastically increases the mobility of carrier, both ionic and electronic ones.It is suggested from IR spectra that the structure of glasses consists mainly of metaphosphate chains.The halide anions remaining outside the phosphate chain will enhance the movements of the carrier by forming the pair of Cu+ ion with them.

Solid electrolyte cells with a copper ion conductor Rb4Cu16I7Cl13. IV. Mixed-phase cathodes containing metal oxides

Solid electrolyte cells Cu, X/X/(MO, C, X), have been investigated (X; Rb4Cu16I7Cl13, MO; metal oxide, and C; graphite). An electrolytic manganese dioxide was used as a model oxide for preparing three types of cathode: (1) only MO, (2) a mixture of MO and C, and (3) a mixture of MO, C and X. Cell performances depended not only on the composition of the mixed-phase cathode, but also on the uniformity of the mixture of the materials. Several cells with metal oxides such as MnO2, V2O5, and WO3, showed high and stable electromotive forces of 0.546–0.575 V and good discharge behaviour at room temperature.

Rechargeable all solid-state cell with high copper ion conductor and copper chevrel phase

A new type of rechargeable solid-state cells, Cu xMo 6S 8−y Rb 4 Cu 16 I 7 Cl 13 Cu xMo 6 S 8− y , has been developed. The coulometric titration curves of the copper Chevrel phase enabled us to determine the composition ranges, which are available both for an anode (1.1<x<4.0 in Cu xMo 6S 7.8) and for a cathode (0.2<x<1.1 in Cu xMo 6S 7.8). The Cu 3.8 Mo 6 S 7.8 Cu 0.2 Mo 6 S 7.8 couple yielded an open-circuit voltage of 0.55V and a current of several hundreds of micro-amperes with high cathode efficiency at room temperature. The cell was submitted to a thousand or more charge-discharge cycles without showing appreciable deterioration at a current density of 375μA/cm 2. The copper ion distribution in the Chevrel phase was further discussed on the basis of coulometric titration curves.

Rechargeable solid electrolyte cells with a copper ion conductor, RB 4Cu 16I 7−xCl 13+x

A high performance secondary solid electrolyte cells with a high copper ion conductor, Rb 4Cu 16I 6.8Cl 13.2, has been developed. The cell using copper-Chevrel phase, Cu 4Mo 6S 8, as an anode and a layered copper intercalation compound, NbS 2, as a cathode produced a high discharge capacity and a good rechargeability. At a current density of 150μA/cm 2, the cathode capacity was above 60mAhr/g(0.3 e/NbS 2) and even at 750μA/cm 2 it was 48mAhr/g(0.24 e/NbS 2). On the charge-discharge cycle test of 75μA/cm 2 and 0.3%e/NbS 2 depth, the cell did not show a significant deterioration in the charge-discharge curves during 500 or more cycles.

Single and multi-layerbuilt solid electrolyte cells with a copper ion conductor

The performances of two types of solid electrolyte cell were investigated. One was a single-layer cell Cu,X/X/Cu2Se,Se (Se/Cu2Se=3 in weight) where X was a copper ion conductor Rb4Cu16I7Cl13. The open circuit voltage (OCV) of the cell was 385 mV at room temperature and was stable after 250 days. Appreciable polarization could not be observed up to about ten microamperes of discharge rate. The other was the multi-layerbuilt cell consisting of two, three or five single cells. As expected, the OCVs and the overpotentials of the layerbuilt cells were nearly proportional to the number of single cells assembled.

Photointercalation and Optical Information Storage Using Cu6 − x PS 5 I

The agyrodite is simultaneously a copper ion conductor and a p‐type electronic semiconductor. With an energy gap of , the compound intercalates copper upon illumination as demonstrated in photoelectrochemical experiments. The intercalation of copper is accompanied by a color change which is believed to be due to an annihilation of color centers. In experiments in which Cu was partially replaced by Ag, photointercalation was verified by means of x‐ray fluorescence measurements. It is shown how such a photointercalation reaction could be used to store optical information.

Coulometric titration of copper in Cu xMo 6S 8−y(0⩽y⩽0.4) with solid Cu-electrolyte Rb 4Cu 16I 7Cl 13

In order to determine the copper content x of copper Chevrel compound Cu x Mo 6S 8−y(0⩽ y⩽0.4) as a function of copper activity a Cu and sulfur deficit y, a solid state electrochemical cell, Cu/Rb 4Cu 16I 7Cl 13/Cu x Mo 6S 8−y/Pt, was constructed and coulometric titration studies were made at 400 K. For the evaluation of the coulometric titration data, measurements were made on the electronic conductivity of copper-ion conductor Rb 4Cu 16I 7Cl 13. Also, a brief investigation was made on the condition of formation of single phase Chevrel Cu x Mo 6S 8−y with varying x and y at 1000°C. The structural change of Cu x Mo 6S 8−y with a change in x and y was studied by the X-ray diffraction method. It was found that x for constant a Cu decreases with increasing y. The maximum value x max of x in Cu x Mo 6S 8−y in equilibrium with metallic copper was found to be expressed by x max =-( 10 3 )y+5 . In the region of y<0.3, x max exceeded 4, contrary to a presupposition that x max is less than 4. X-ray analysis revealed that most of the copper Chevrel compounds denoted by Cu x Mo 6S 8 so far were sulfur deficient ones with y≅0.4. The importance of sulfur deficit on the properties of the copper Chevrel compound was emphasized.

Phase diagram and high copper ion conductivity of the copper(I) chloride-rubidium chloride system

The phase diagram of the CuCl—RbCl system has been determined by differential thermal analysis, X-ray diffraction analysis and electrical conductivity measurement. This system contains six intermediate compounds, Rb 2CuCl 3, RbCuCl 2, Rb 11Cu 14Cl 25, Rb 9Cu 16Cl 25, RbCu 2Cl 3 and Rb 3Cu 7Cl 10. Of these intermediate compounds, Rb 9Cu 16Cl 25 has a congruent melting-point at 169°C, and the other compounds have the incongruent melting-points. A single crystal of Rb 9Cu 16Cl 25 was prepared and the crystal form was determined to be cubic (space group I4 132) with a = 21.225 Å. Rb 3Cu 7Cl 10 has a high copper ion conductivity of 3.32 × 10 -3 S cm -1 at 25°C, while the other compounds are poor conductors.

Rechargeable solid electrolyte cells with a copper ion conductor, Rb4Cu16I7??Cl13+?, and a titanium disulphide cathode

A rechargeable solid electrolyte cell has been developed using a high copper-ion-conductivity solid electrolyte, Rb4Cu16I7−δCl13+δ, a copper anode, and an intercalation cathode, TiS2. The open-circuit voltage was 0.59 V at 25° C. The cell yielded a current of several tens of microamperes at room temperature without appreciable polarization. The cell could be submitted to one hundred or more charge-discharge cycles without showing appreciable deterioration.

Preparation and electrical conductivity of thin films of Rb4Cu16I7Cl13

A thin film of the copper ion conductor Rb4Cu16I7Cl13 was prepared on a glass plate by vacuum evaporation. An appropriate thin film was obtained by controlling the amount of the electrolyte mounted in a boat, the evaporation time etc. and by heating the deposited film at a temperature between 130 and 210° C. The electronic and ionic conductivities of the film measured by d.c. and a.c. techniques were nearly equal to those of a dense tablet of the solid electrolyte.

Polarization study on the solid electrolyte Cu16Rb4I7+xCl20-(7+x) (0≲x≲1)

The electronic conductivities of the copper ion conductors Cu16Rb4Cl12I8 and Cu16Rb4Cl13I7 have been measured by a d.c. polarization technique. The concentrations of electron holes in these materials were determined as a function of temperature from an analysis of transient currents in polarized cells. The electronic conductivity exhibits an activation energy of 1 eV and a room-temperature value of 5×10−16(ω cm)−1. The electron hole concentration ranges from 109cm−3 at room temperature to about 1011cm−3 at 130°C, and the transference number for the electron holes ranged from 10−15 at 25°C to 10−11 at 140°C.

Preparation and characterization of the solid electrolyte system RbCu4i2− xCl3+ x (−0.25⩽ x⩽0.75)

The quaternary system RbCu 4I 2− x Cl 3+ x (−0.25⩽0.75) which includes the high copper ion conductivity solid electrolyte Rb 4Cu 16I 7Cl 13 has been studied by means of X-ray diffraction, photoacoustic spectroscopy, X-ray photoelectron spectroscopy, and electrical conductivity measurements. Samples were prepared starting with purified CuCl, CuI, and RbI. It was found that the lattice constant of the solid electrolyte varies from 10.011 to 10.019 Å (±0.002 Å) within the range 0.125< x<0.25. This fact indicates the existence of a solid solution in a narrow compositional range.

Solid-state electrochemical studies of the mixed conductor Cu xMo 6S 8−y. I. Partial copper ion conductivity and chemical diffusion

The partial copper ion conductivity and chemical diffusion coefficient of the phase CuxMo6S8−y (y=0.30+0.15) have been determined as a function of x (1.5