Lithium coin-type

These lithium coin cells generally use a metal oxide intercalation compound for the positive active material and a hthium alloy, such as lithium aluminum, which is less reactive than metallic lithium, for the negative electrode. An organic solution is used for the electrolyte. The energy density and specific energy of the different rechargeable lithium coin-type batteries are summarized in Fig. 34.36. 

FIGURE 34.36 Energy density and specific energy of rechargeable lithium coin-type batteries. 

Lithium-Aluminum Vanadium Pentoxide Batteries. The LiAl/V205 cell is another rechargeable lithium coin-type battery with a low self-discharge rate (2% per year at 20°C) which can be used for low-drain loads. Over 1000 cycles can be obtained at 10% depth of discharge. The construction is similar to the one illustrated in Fig. 34.37, except that V2OS is used for the active positive material. 

FIGURE 34.44 Charge characteristics of a carbon-lithium coin-type battery (CL2020 size) with solar batteries. (From Panasonic Division of Matsushita Electric Corp. of America.)... 

TABLE 34.22 Rechargeable Carbon-Lithium Coin-Type Batteries... 

Secondary batteries can be electrically charged, and these batteries can offer savings in costs and resources. Recently, lithium-ion and nickel-metal hydride batteries have been developed, and are used with the other secondary batteries, such as nickel-cadmium, lead-acid, and coin-type lithium secondary batteries. 

The cathode of coin-type batteries consists of Mn02 with the addition of a conductive material and binder. The anode is a disk made of lithium metal, which is pressed onto the stainless steel anode can. The separator is nonwoven cloth made of polypropylene, which is places between the cathode and the anode. 

Li-Mn02 batteries are available in a variety of shapes and construction [30] in accordance with their particular use. Figure 32 shows various applications of lithium batteries based on their drain current. Coin-type batteries are generally used for low-rate drain. Cylindrical batteries with the inside-out construction can serve as a... 

Table 1. Specifications of coin-type manganese dioxide-lithium batteries...

Table 8. Specification of coin-type lithium-carbon monofluoride batteries for high-temperature range...

Table 1. Commercially available rechargeable coin-type cells with lithium-metal alloys...

Figure 6. Lithium cycling efficiency of composite lithium anodes in an Li/a -V205 coin-type cell (thickness 2 mm, diameter 23 mm) with 1.5 mol L 1 LiAsF6 - EC/2MeTHF. ...

In-situ x-ray diffraction (XRD) was performed on a coin type cell with a 4x6 mm Kapton window coated with conductive thin copper layer. The graphite electrode was pressed against the Kapton window so as to be reached by the x-ray beam. After several lithiation/delithiation cycles under a C/10 rate between 1.5 and 0V, the cell was fully delithiated up to 1.5V. The cycle capacity achieved with the graphite electrode is about 360mAh/g. The cell was then re-lithiated under a slower rate of C/20. XRD patterns were taken for about five minutes every hour while the cell is under continuous discharge. As result the lithium composition x in LixC6 was incremented by 0.05 between two successive XRD scans. 

Coin-type cells (size CR2032, Hohsen Co.) with a lithium foil counter electrode (FMC Corporation) and a polypropylene separator (Celgard 3501) were assembled inside a helium-filled glovebox (<5ppm, H20 and 02). Laboratory made cell fixtures were also used for the HPPC test at room temperature. 

Further on, the Co-Ni complexes were used for modification of Hohsen Carbon type (10-10) and Hohsen Graphite type (10-28) anode materials for Li-ion batteries applying similar procedure. These anode materials were tested in 2016 size lithium coin cells with a configuration Li/electrolyte (LP-30)/(modified anode material). The coin cells were assembled by standard technology in dry atmosphere of a glove box and then... 

Preliminary electrochemical tests of materials obtained have been performed in two types of cells. Primary discharge measurements have been executed in standard 2325 coin-type cells (23 mm diameter and 2.5 mm height) with an electrolyte based on propylene carbonate - dimethoxyethane solution of LiC104. Cathode materials have been prepared from thermally treated amorphous manganese oxide in question (0.70 0.02g, 85wt%.) mixed with a conductive additive (10 % wt.) and a binder (5wt%). Lithium anodes of 0.45 mm thickness have been of slightly excess mass if compared to the stoichiometric amount, so as to ensure maximal possible capacity of a cell and full consumption of the cathode material. 

There have been a number of attempts to produce commercial lithium rechargeable batteries. The V205 positive is currently used by the Matsushita Battery Industrial Co in Japan for the production of small capacity, coin-type cells. Fig. 7.24 shows a cross-section of one prototype. For the construction of the battery, V205 and carbon black are mixed together with a binder, moulded and vacuum-dried to form the positive electrode pellet. A solution of LiBF4 in a propylene carbonate-y-butyrolactone-1,2-dimethoxyethane mixture absorbed in a polypropylene separator is used as the electrolyte. 

As mentioned above, a coin type Li polymer battery has high performance. In particular, the PMMA gel electrolyte is very stable toward lithium anodes. 

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