Lithium-copper oxide cells

The lithium-copper oxide cell is voltage compatible (OCV = 1.5 V), i.e. it may be used as a direct replacement for conventional Leclanche or alkaline zinc cells. CuO has a particularly high volumetric capacity (4.2 Ah/cm3) so that cells are characterized by high specific energy -300 Wh/kg (700 Wh/dm3). The discharge curve shows a single step which may be attributed to the simple displacement reaction ... 

The lithium-copper oxyphosphate cell has similar features to the lithium-copper oxide cell, but has a somewhat higher voltage. The cell reaction is written as... 

The lithium-copper oxide cells used in this investigation were made by SAFT and had a type specification LCOl. Each cell has a negative electrode of lithium metal, an electrolyte of lithium perchlorate in an organic solvent and a positive electrode of copper oxide and carbon. The cell is constructed in the form of a hollow tubular lithium central cylinder which is separated by a thin annular synthetic material from a concentric tubular copper oxide-carbon ring matrix enclosed by an outer steel can. Current collectors are attached to the lithium and steel cylinders. 

Table 9.10 Characteristics of lithium-copper oxide cells...

Figure 30.23 shows a performance comparison of a lithium-copper oxide cell which has been stored at desert temperatures for 5 years (solid line) against that of a new cell (dashed line). 

Figure 30.23 SAFT lithium-copper oxide cells voltage-time shelf-life curves (Courtesyof SAFT)...

Figure30.56 1, SAFT LC01 1.5 V (3.6Ah) lithium-copper oxide cell 2, alkaline K6 zinc-manganese dioxide cell. Capacity versus discharge current at various operating temperatures. The superiority of the lithium-copper oxide couple at low drain is evident (Courtesy...

Bobbin and eylindrieal eell formats are available from Saft. Other suppliers of lithium-copper oxide cells include Eagle Picher and Sanyo (Japan) (button cells). 

The cylindrical cells supplied by SAFT have an open-circuit voltage of 2.8 V and a nominal voltage of 2.8 V, as opposed to the 1.5 V nominal voltage available from lithium-copper oxide cells. These cells are designed to operate at temperatures up to 175°C with high reliability. Details of the available range of these cells are supplied in Table 56.19. 

Fig. 4.23 Discharge curves of lithium-copper oxide button cells (LC 01) after accelerated shelf testing at 70°C (a) fresh cell (b) after 6 months at 70°C (c) after 12 months at 70°C (d) after Jfi months at 70°C, (By courtesy of SAFT Gipelec.)...

Fig. 4. 25 Comparison of discharge curves at ambient temperature of voltage-compatible lithium-copper oxide button cells and conventional aqueous cells (a) lithium-copper oxide (b) alkaline manganese (c) zinc-silver oxide. Load = 75 k i...

The impedance of small lithium-copper oxide primary cells has been investigated in a frequency range from 5 mHz to 10 kHz. The cells had been stored after assembly for from three weeks up to three years and their state of charge was from 100% down to 20%. After an initial period of electrochemical stabilization, the cells exhibited consistent results and the shape of the impedance locus was found to depend markedly on the state of charge of the cell. An interpretation of the results is given in terms of an analogue circuit which contains components to represent the contribution to the impedance of each electrode and of the electrolyte. 

LITHIUM/COPPER OXIDE Li/CuO) AND LITHIUM/COPPER OXYPHOSPHATE [Li/Cu OiPOJz] CELLS... 

Like any common batteries, lithium batteries will rupture if exposed to fire. The low-rate lithium batteries, intended for watches, should be safe if used within manufacturers specified temperatures. Thick separators in these low-rate cells prevent shorting and their small size permits easy heat dissipation if any local internal reactions should occur. In fact, a good case can be made that most low-rate lithium cells are safer than zinc-mercury cells, which can introduce poisonous mercury into the atmosphere when incinerated. SAFI supply lithium-copper oxide... 

Lithium-copper oxide primary cells have been established since 1969 as a versatile and reliable power source in a range of applications. 

The lithium-copper oxide battery has two special characteristics. Its initial voltage is approximately 2 V, but when fully loaded it drops to a flat 1.5 V. Thus it can be used as a direct replacement for carbon and alkaline cells. (Most other lithium batteries have voltages from 2.8 to 3.5 V.) Lithium-copper oxide also has a wide temperature range, spanning —55 to -H25°C. Although it is not the highest performance lithium combination, its voltage and temperature characteristics permit applications in specific niches. 

These researches opened the door to the fabrication and commercialization of varieties of primary hthium batteries since the late l%0s nonaqueous hthium cells, especially the 3-V primary systems, have been developed. These systems include lithium-sulfur dioxide (Li//S02) cehs, lithium-polycarbon monofluoride (Li//(CF t) ) cells introduced by Matsuschita in 1973, lithium-manganese oxide (Li//Mn02) cells commercialized by Sanyo in 1975, lithium-copper oxide (Li//CuO) cells, lithium-iodine (Li//(P2VP)1J cells. During the same period, molten salt systems (LiCl-KCl eutecticum) using a Li-Al alloy anode and a FeS cathode were introduced [1]. The lithium-iodine battery has been used to power more than four million cardiac pacemakers since its introduction in 1972. During this time the lithium-iodine system has established a record of reliability and performance unsurpassed by any other electrochemical power source [18]. 

Initially the central cavity of the cell is filled with electrolyte solution that passes by capillary action into the copper oxide-carbon matrix which swells to form a spongy mass. After a time, all the electrolyte is removed from the central cavity and becomes distributed homogeneously throughout the space between the lithium and the steel cylinders. After an initial period of electrochemical stabilization, very little further change occurs and the cell is available for use. 

Tbe constraction of the Li/CuO button-type battery shown in Fig. 14.87a is similar to other conventional and lithium/solid-cathode cells. Copper oxide forms the positive electrode and lithium the negative. The electrolyte consists of lithium perchlorate in an organic solvent (dioxolane). 

For the reference electrode of a three-electrode electrochemical cell, the end tip of the Teflon coated copper wire was removed. Lithium titanium oxide (Li4Ti50i2, Altair) was coated on the bare copper [36, 37]. The reference electrode was located between two separators, as shown in Figure 8(b). Before conducting the electrochemical tests, the state of charge of the lithium titanium oxide was set to 50%, and in this state its potential was approximately 1.57 V (vs. All of the cells were assembled in a glove box (MBraun,... 

A typical lithium-ion cell consists of a positive electrode composed of a thin layer of powdered metal oxide (e.g., LiCo02) mounted on aluminum foil and a negative electrode formed from a thin layer of powdered graphite, or certain other carbons, mounted on a copper foil. The two electrodes are separated by a porous plastic film soaked typically in LiPFe dissolved in a mixture of organic solvents such as ethylene carbonate (EC), ethyl methyl carbonate (EMC), or diethyl carbonate (DEC). In the charge/ discharge process, lithium ions are inserted or extracted from the interstitial space between atomic layers within the active materials. 

Conditioning of the manganese oxide suspension with each cation was conducted in a thermostatted cell (25° 0.05°C.) described previously (13). Analyses of residual lithium, potassium, sodium, calcium, and barium were obtained by standard flame photometry techniques on a Beckman DU-2 spectrophotometer with flame attachment. Analyses of copper, nickel, and cobalt were conducted on a Sargent Model XR recording polarograph. Samples for analysis were removed upon equilibration of the system, the solid centrifuged off and analytical concentrations determined from calibration curves. In contrast to Morgan and Stumm (10) who report fairly rapid equilibration, final attainment of equilibrium at constant pH, for example, upon addition of metal ions was often very slow, in some cases of the order of several hours. 

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