Amorphous Cathodes for Lithium Batteries
Interest in ambient temperature secondary lithium batteries has focused recently on the use of crystalline layered compounds as cathode materials (1). In particular the dichalcogenide, TiS2, has been found to possess many of the characteristics desired of a secondary electrode, such as a continuous non-stoichiometric phase, LixTiS2 for o<χ<l, high electron conductivity, and high free energy of reaction. Many of the other dichalcogenides show similar but generally inferior electrochemical characteristics. However, amongst the group VIB dichalcogenides, crystalline molybdenum disulfide only intercalates about 0.1 Li/Mo and the tungsten compounds react directly to the lithium chalcogenide, Li2S or Li2Sε. This behavior is just that expected from thermodynamic calculations. Ideally to achieve optimum energy storage capacity, either volumetric or gravimetric, reaction with more than one alkali metal per transition metal is desired without breaks in the discharge curve as observed with VSe2. Although some crystalline trichalcogenides such as TiS3, MoO3 and NbSe3 have been studied only one, NbSe3, shows significant reversibility under deep discharge conditions and it contains heavy, expensive and toxic components; moreover, its gravimetric energy density under load is less than that of TiS2. This paper discusses some initial work on a new class of cathode materials, amorphous transition metal chalcogenides. As examples, the properties of MoS2, MoS3 and V2S5 will be described (2).
KeywordsCathode Material Molybdenum Disulfide Lithium Batterie High Electron Conductivity Cycle Behavior
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- 2.A. J. Jacobson, R. R. Chianelli and M. S. Whittingham, U.S. Patents 4,144,384 and 4,166,160 and J. Electrochem. Soc., Mat. Res. Bull., and J. Less Common Metals, in press.Google Scholar
- 4.)A. J. Jacobson, R. R. Chianelli and M. S. Whittingham, J. Electrochem. Soc., 127, (1980).Google Scholar
- 5.)B. M. L. Rao devised this technique.Google Scholar
- 6.)L. P. Klemann and G. H. Newman, U.S. Patent, 4,117,213.Google Scholar
- 8.)S. P. Cramer, K. Liang et al., in press.Google Scholar