Lithium batteries are primarybatteries that have lithium metal or lithium compounds as an anode. Depending on the design and chemical compounds used lithium cells can produce voltages from 1.5 V to about 3 V, twice the voltage of an ordinary zinc-carbon battery or alkaline cell. Lithium batteries are used in many portable consumer electronic devices, and are widely used in industry.
The term "lithium battery" refers to a family of different chemistries, comprising many types of cathodes and electrolytes. One type of lithium cell having a large energy density is the lithium-thionyl chloride cell. In this cell, a liquid mixture of thionyl chloride and lithium tetrachloroaluminate acts as the cathode and electrolyte respectively. A porous carbon material serves as a anode current collector which receives electrons from the external circuit. However, lithium-thionyl chloride batteries are generally not sold to the consumer market, and find more use in commercial/industrial applications, or are installed into devices where no consumer replacement is performed. Lithium-thionyl chloride batteries are well suited to extremely low-current applications where long life is necessary, e.g. wireless alarm systems.
The most common type of lithium cell used in consumer applications uses metallic lithium as anode and manganese dioxide as cathode, with a salt of lithium dissolved in an organic solvent.
The most common consumer grade battery, about 80% of the lithium battery market. Uses inexpensive materials. Suitable for low-drain, long-life, low-cost applications. High energy density per both mass and volume. Can deliver high pulse currents. Wide temperature range. With discharge the internal impedance rises and the terminal voltage decreases. Maximum temperature limited to about 60 °C. High self-discharge at high temperatures.
Liquid cathode. For low temperature applications. Can operate down to -55 °C, where it retains over 50% of its rated capacity. Negligible amount of gas generated in nominal use, limited amount under abuse. Has relatively high internal impedance and limited short-circuit current. High energy density, about 500 watt-hour/kilogram. Toxic. Electrolyte reacts with water. Low-current cells used for portable electronics and memory backup. High-current cells used in military applications. In long storage forms passivation layer on anode, which may lead to temporary voltage delay when put into service. High cost and safety concerns limit use in civilian applications. Can explode when shorted. Underwriters Laboratories require trained technician for replacement of these batteries. Hazardous waste.
Liquid cathode. A variant of the thionyl chloride battery, with 300 mV higher voltage. The higher voltage drops back to 3.5 V soon, as the bromine chloride gets consumed during the first 10-20% of discharge. The cells with added bromine chloride are thought to be safer when abused.
Liquid cathode. Similar to thionyl chloride. Discharge does not result in buildup of elemental sulfur, which is thought to be involved in some hazardous reactions, therefore sulfuryl chloride batteries may be safer. Commercial deployment hindered by tendency of the electrolyte to corrode the lithium anodes, reducing the shelf life. Chlorine is added to some cells to make them more resistant to abuse. Sulfuryl chloride cells give less maximum current than thionyl chloride ones, due to polarization of the carbon cathode. Sulfuryl chloride reacts violently with water, releasing hydrogen chloride and sulfuric acid.
Lithium bromide in sulfur dioxide with small amount of acetonitrile
Liquid cathode. Can operate down to -55 °C and up to +70 °C. Contains liquid SO2 at high pressure. Requires safety vent, can explode in some conditions. High energy density. High cost. At low temperatures and high currents performs better than Li-MnO2. Toxic. Acetonitrile forms lithium cyanide, and can form hydrogen cyanide in high temperatures. Used in military applications.
Addition of bromine monochloride can boost the voltage to 3.9 V and increase energy density.
Cathode material formed by high-temperature intercalation of fluorine gas into graphite powder. High energy density (250 Wh/kg), 7 year shelf life. Used for low to moderate current applications, eg. memory and clock backup batteries. Very good safety record. Used in aerospace applications, qualified for space since 1976. Used in military applications both terrestrial and marine, and in missiles. Also used in cardiac pacemakers. Maximum temperature 85 °C. Very low self-discharge (<0.5%/year at 60 °C, <1%/yr at 85 °C). Developed in 1970s by Matsushita.
Solid electrolyte. Very high reliability. Used in medical applications. Does not generate gas even under short circuit. Solid-state chemistry, limited short-circuit current, suitable only for low-current applications. Terminal voltage decreases with degree of discharge due to precipitation of lithium iodide. Low self-discharge.
Very high reliability. Has a 2.6 V plateau after reaching certain percentage of discharge, provides early warning of impending discharge. Developed specifically for medical applications, eg. implanted pacemakers.
lithium hexafluorophosphate or lithium hexafluoroarsenate in propylene carbonate with dimethoxyethane
Used in medical applications, eg. implantable defibrillators, neurostimulators, and drug infusion systems. Also projected for use in other electronics, eg. emergency locator transmitters. High energy density. Long shelf life. Capable of continuous operation at nominal temperature of 37 °C. Two-stage discharge with a plateau. Output voltage decreasing proportionally to the degree of discharge. Resistant to abuse.
Addition of copper oxide to the cathode material results in the Li-CSVO variant.
Can operate up to 150 °C. Developed as a replacement of zinc-carbon and alkaline batteries. "Voltage up" problem, high difference between open-circuit and nominal voltage. Produced until mid-1990s, replaced by lithium-iron sulfide. Current use limited.
"Lithium-iron", "Li/Fe". Used in eg. Energizer lithium cells as a replacement for alkaline zinc-manganese chemistry. Called "voltage-compatible" lithiums. 2.5 times higher lifetime for high current discharge regime than alkaline batteries, no advantage for low-current applications. Low self-discharge, 10 years storage time. FeS2 is cheap. Some types rechargeable. Cathode often designed as a paste of iron sulfide powder mixed with powdered graphite. Variant is Li-CuFeS2.
Replacement of silver-oxide batteries, with higher energy density, lower tendency to leak, and better performance at higher temperatures.
The liquid organic electrolyte is usually a solution of an ion-forming inorganic lithium compound in a mixture of a high-permittivity solvent (eg. propylene carbonate) and a low-viscosity solvent (eg. dimethoxyethane).
Lithium batteries find application in many long-life, critical devices, such as artificial pacemakers and other implantable electronic medical devices. These devices use specialized lithium-iodide batteries designed to last 15 or more years. But for other, less critical applications such as in toys, the lithium battery may actually outlast the toy. In such cases, an expensive lithium battery is not cost-efficient.
Lithium batteries can be used in place of ordinary alkaline cells in many devices, such as clocks and cameras. Although they are more costly, lithium cells will provide much longer life, thereby minimizing battery replacement. However, attention must be given to the higher voltage developed by the lithium cells before using them as a drop-in replacement in devices that normally use ordinary cells.
Small lithium batteries are very commonly used in small, portable electronic devices, such as PDAs, watches, thermometers, and calculators, as backup batteries in computers and communication equipment, and in remote car locks. They are available in many shapes and sizes, with a common variety being the 3 volt "coin" type manganese variety, typically 20 mm in diameter and 1.6–4 mm thick. The heavy electrical demands of many of these devices make lithium batteries a particularly attractive option. In particular, lithium batteries can easily support the brief, heavy current demands of devices such as digital cameras, and they maintain a higher voltage for a longer period than alkaline cells.
Some other lithium batteries use a platinum-iridium alloy instead of more usual compounds. These batteries are generally not preferred, as their cost is high and they tend to be fragile.
Safety issues and regulation
The United States Transportation Security Administration announced restrictions effective 2008-01-01 on lithium batteries in checked and carry on luggage. The rules forbid lithium batteries not installed in a device from checked luggage and restrict them in carry-on luggage by total lithum content.
Lithium batteries can provide extremely high currents and can discharge very rapidly when short-circuited. Although this is useful in applications where high currents are required, a too-rapid discharge of a lithium battery can result in overheating of the battery, rupture, and even explosion. Lithium-thionyl chloride batteries are particularly capable of this type of discharge. Consumer batteries usually incorporate overcurrent or thermal protection or vents in order to prevent explosion.
Because of the above risks, shipping and carriage of lithium batteries is restricted in some situations, particularly transport of lithium batteries by air.
The computer industry's drive to increase battery capacity can test the limits of sensitive components such as the membrane separator, a polyethylene or polypropylene film that is only 20-25 µm thick. The energy density of lithium-ion batteries has more than doubled since they were introduced in 1991. When the battery has more and more material, the separator can undergo stress.
Lithium batteries and methamphetamine labs
Unused lithium batteries provide a convenient source of lithium metal for use as a reducing agent in illegal methamphetamine labs. Some jurisdictions have passed laws to restrict lithium battery sales or asked businesses to make voluntary restrictions in an attempt to help curb the creation of illegal meth labs. For example a newspaper article from January 2004 reports that Wal-Mart stores limit the sale of disposable lithium batteries to three packages in Missouri and four packages in other states. However, the heavy demand for lithium batteries for use in modern, current-hungry devices such as digital cameras conflicts with such restrictions.