Solid-electrolyte batteries characteristics

Solid electrolyte batteries are currently available in a button or circular disc configuration, with a nominal 25.4mm diameter and rated at 350mA h. Table 9.12 summarizes the major physical and electrical characteristics of these batteries. 

The performance characteristics of lithium solid electrolyte batteries are shown in Table 9.13. 

Dry cells (batteries) and fuel cells are the main chemical electricity sources. Diy cells consist of two electrodes, made of different metals, placed into a solid electrolyte. The latter facilitates an oxidation process and a flow of electrons between electrodes, directly converting chemical energy into electricity. Various metal combinations in electrodes determine different characteristics of the dry cells. For example, nickel-cadmium cells have low output but can work for several years. On the other hand, silver-zinc cells are more powerful but with a much shorter life span. Therefore, the use of a particular type of dry cell is determined by the spacecraft mission profile. Usually these are the short missions with low electricity consumption. Diy cells are simple and reliable, since they lack moving parts. Their major drawbacks are... 

PEO and Related Systems. High ionic conductivities have been characteristically associated with polymer-alkali metal complexes, which are receiving great deal of research attention as electrolytes for solid state batteries. LiC104 dispersed homogeneously in cross-linked (P-cyanoethyl methylsiloxane) polyO-cyano-ethyl methylsiloxane-co-dimethylsiloxane) shows a network film conducting in the order of 10 s ohm-1 cm-1 at room temperature [106]. 

Electrons participating in the intercalation/deintercalation reaction (Equation (5.1)) can be represented by a current-producing system. Second, it is characteristic that the current-producing system reversibly operated by a self-driven (galvanic) cell (discharging the battery) performs the electrical useful work AG = —zFE (where E is the EMF of the cell), because electrical potential difference is spontaneously developed between two electrodes. By contrast, when the cell is short-circuited - that is, when the two electrodes are not separated from each other but are directly in electrical contact - electrons do not appear explicitly but rather participate in corrosion (or permeation in the case of solid electrolyte cells). They perform no electrical useful work because the two electrodes have the same electrical potential. 

Much attention is now focused on whether or not solid electrolytes can be commercialized. Inorganic solid electrolytes have achieved ionic conductivity equivalent to current liquid electrolyte solutions. If such solid electrolytes can be commercialized, they are expected to revolutionize LIB electrode structure and battery characteristics. 

Several batteries based on solid electrolytes are also made and the chemistry and characteristics of one are included in Table 11.7. Such cells can only be discharged at low currents and therefore give an extremely poor power density. On the other hand their great reliability make them well suited for low powered electronic circuitry and medical implants. 

Of practical importance is the contribution that is made by carbonaceous materials as an additive to enhance the electronic conductivity of the positive and negative electrodes. In other electrode applications, carbon serves as the electrocatalyst for electrochemical reactions and/or the substrate on which an electrocatalyst is located. In addition, carbonaceous materials are fabricated into solid structures which serve as the bipolar separator or current collector. Clearly, carbon is an important material for aqueous-electrolyte batteries. It would be very difficult to identify a practical alternative to carbon-based materials in many of their battery applications. The attractive features of carbon in electrochemical applications are its high electrical conductivity, acceptable chemical stability, and low cost. These characteristics are important for the widespread acceptance of carbon in aqueous electrolyte batteries. 

P(Py), along with P(ANi), represents the CP most commonly investigated for commercially practical secondary batteries. Li/P(Py) Queries exhibit good discharge characteristics and cyclability, as Table 15-1 reveals. Typical discharge and charge reactions for a standard, Li/LiC104-liquid or solid electrolyte/P(Py) battery, are very similar to those cited for P(Ac) above. We may now briefly discuss illustrative, individual examples of P(Py) batteries and improvements therein. 

MURATA K (1995), An overview of the research and development of solid polymer electrolyte batteries , Electrochim Acta, 40 2177-2184 NiSHiMOTO A, WATANABE M, iKEDA Y and KOHJiYA s (1998), High ionic conductivity of new polymer electrolytes based on high molecular weight polyether comb polymers , Electrochim Acta, 43(10-11) 1177-1184 OH B and KIM Y R (1999), Evaluation and characteristics of a blend polymer for a solid polymer electrolyte . Solid State Ionics, 124 83-89 OMATA T and MAKOTO K (1998), Lithium ion-conductive polymer electrolyte and lithium ion battery , European Patent No.0854527 OWENS B B and Osaka t (1997), Panel discussion future prospects of lithium batteries , J Power Sources, 68 173-186... 

Besenhard JO, Heydecke J, Wudy E, Fritz HP, Foag W (1983) Characteristics of molybdenum oxide and chromium oxide cathodes in primary and secondary organic electrolyte batteries. II. Transport properties. Solid State Ionics 8 61-71... 

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