Lithium high energy

The small lithium Li" and beryllium Be ions have high charge-radius ratios and consequently exert particularly strong attractions on other ions and on polar molecules. These attractions result in both high lattice and hydration energies and it is these high energies which account for many of the abnormal properties of the ionic compounds of lithium and beryllium. 

Figure 7.5 shows these series schematically for lithium. All such series converge smoothly towards high energy (low wavelength) in a way that resembles the series in the hydrogen spectrum. 

High energy density batteries with long shelf life, developed originally for military use, are based on lithium and thionyl chloride. These batteries are used ia backup or standby power sources for computer, missile, and telephone systems (191,192). 

Lithium—Thionyl Chloride Cells. Lidiium—thionyi chloride cells have very high energy density. One of the main reasons is the nature of the ceU reaction. 

Because of lithium s low density and high standard potential difference (good oxidation reduction characteristics), cells using lithium at the anode have a very high energy density relative to lead, nickel and even zinc. Its high cost limits use to the more sophisticated and expensive electronic equipment. 

Cylindrical batteries can be classified into two basic types one with a spiral structure, and one with an inside-out structure. The former consists of a thin, wound cathode and the lithium anode with a separator between them. The latter is constructed by pressing the cathode mixture into a high-density cylindrical form. Batteries with the spiral construction are suitable for high-rate drain, and those with the inside-out construction are suitable for high energy density. 

Lithium-vanadium oxide rechargeable batteries were developed as memory backup power sources with high reliability and high energy density. 

Specific Problems in Designing High-Volume, High-Energy, Reliable Lithium-Ion Batteries... 

There is no question that the development and commercialization of lithium ion batteries in recent years is one of the most important successes of modem electrochemistiy. Recent commercial systems for power sources show high energy density, improved rate capabilities and extended cycle life. The major components in most of the commercial Li-ion batteries are graphite electrodes, LiCo02 cathodes and electrolyte solutions based on mixtures of alkyl carbonate solvents, and LiPF6 as the salt.1 The electrodes for these batteries always have a composite structure that includes a metallic current collector (usually copper or aluminum foil/grid for the anode and cathode, respectively), the active mass comprises micrometric size particles and a polymeric binder. 

Due to its high energy density (3,860 mAh/g) and low voltage, lithium is the most attractive metal of the periodic table for battery application. Unfortunately lithium metal, and most of its alloys cannot be used in rechargeable batteries because of their poor cyclability. Therefore, lithium intercalation compounds and reversible alloys are among today s materials of choice for subject application. The most common active materials for the negative electrodes in lithium-ion battery applications are carbonaceous materials. The ability of graphitized carbonaceous materials to... 

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