All batteries comprise two electrodes at which select chemical reactions occur to produce a stream of electrons flowing from one electrode to the other. One reaction is an oxidation, where electrons are liberated, the other is a reduction, where electrons are consumed. The voltage difference between these two reactions and the flow of electrons are the driving forces that enable the battery to provide electrical power. In a lithium Energizer battery such as dell Inspiron 1525 battery, dell Inspiron 1526 battery, Dell HP297 battery, dell GW240 battery, dell RN873 battery, dell XR693 battery, dell 0XR693 battery, dell 312-0625 battery, Dell Latitude X200 battery, Dell 8U443 battery, Dell Latitude X200 battery, Dell 312-0058 battery, lithium (a light-weight, highly energetic metal) is the negative electrode and a mixture of carbon black, a polymer binder and iron disulfide form the positive electrode. A porous separator and a mixture of a lithium salt dissolved in an organic solvent round out the general composition of this battery. The separator prevents electrical shorting of the two electrodes and the lithium salt in the solvent forms the battery electrolyte. When a load (e.g. a resistor) is placed across the battery terminals, the lithium metal is oxidized forming lithium cations (Li+) which frees electrons from the lithium metal. These electrons flow through the resistor toward the positive terminal of the battery. At the positive electrode, the iron disulfide (FeS2) is oxidized accepting electrons together with the lithium cation to form a new compound, lithium iron disulfide (LiFeS2), which is chemically stable.
However, the reaction sequence is not completed until the LiFeS2 is further oxidized with additional Li+ to eventually form elemental iron (Fe) and lithium sulfide (Li2S).
Significance
This electrochemical couple provides very high energy in a relatively safe system. Because lithium is generally highly reactive, it is difficult to find a cathode reaction that can be energetic, while reacting with lithium in a sufficiently controlled manner to provide a battery that is safe for general consumer use. Iron disulfide is an ideal cathode reactant since it is inexpensive and yields safe reaction products when combined with lithium.
Applications
Lithium Energizer 1.5 V AA and AAA size batteries are direct drop-in replacements for AA and AAA alkaline batteries. According to the Energizer data sheet, they provide much higher energy (AA size; 297 Wh/kg) and longer life than comparable batteries (AA alkaline; 143 Wh/kg). They have excellent shelf life and contain no heavy metals such as NiCad batteries. When using these batteries, the US Dept. of Transportation allows the consumer to carry them onboard aircraft, but only in their carry on luggage. They may not be placed in checked baggage.
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