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A battery, also known as a voltaic cell, is one or more electrochemical galvanic cells which store chemical energy which can be converted to electrical potential energy or electricity.


Zinc-carbon battery - Also known as a standard carbon battery, zinc-carbon chemistry is used in all inexpensive AA, C and D dry-cell batteries. The electrodes are zinc and carbon, with an acidic paste between them that serves as the electrolyte. These batteries are the least expensive primary batteries and are a common choice among manufacturers who sell products that come with batteries.

http://upload.wikimedia.org/wikipedia/en/a/af/Zincbattery.png

the outer zinc container is the anode (minus) . The zinc is oxidized according to the following equation.

Zn(s) → Zn2+(aq) + 2 e-

A graphite rod surrounded by a powder containing manganese(IV) oxide is the cathode(plus) . The manganese dioxide is mixed with carbon powder to increase the conductivity of the cathode mixture. 2MnO2(s) + H2(g)→ Mn2O3(s) + H2O(l)

The H2 comes from the NH4(aq):

2NH4(aq) + 2 e-→ H2(g) + 2NH3(aq)

and the NH3 combines with the Zn2+.

In this half-reaction, the manganese is reduced from an oxidation state of (+4) to (+3).

There are other possible side-reactions, but the overall reaction in a zinc-carbon cell can be represented as:

Zn(s) + 2MnO2(s) + 2NH4+(aq) → Mn2O3(s) + Zn(NH3)22+(aq) + H2O(l)

The battery has an e.m.f. of about 1.5 V. The approximate nature of the e.m.f is related to the complexity of the cathode reaction. The anode (zinc) reaction is comparatively simple with a known potential. Side reactions and depletion of the active chemicals increases the internal resistance of the battery, and this causes the e.m.f. to drop.


Alkaline battery- Alkaline chemistry is used in common Duracell and Energizer batteries. In an alkaline battery, the anode (negative terminal) is made of zinc powder (which allows more surface area for increased rate of reaction therefore increased electron flow) and the cathode (positive terminal) is composed of manganese dioxide. Alkaline batteries are comparable to zinc-carbon batteries, but the difference is that alkaline batteries use potassium hydroxide (KOH) as an electrolyte rather than ammomium chloride or zinc chloride.

Zn (s) + 2OH−(aq) → ZnO (s) + H2O (l) + 2e−

2MnO2(s) + H2O (l) + 2e−→Mn2O3(s) + 2OH−(aq)


Lithium batteries

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.

Chemistry

Cathode

Electrolyte

Nominal voltage

Open-circuit voltage

Wh/kg

Wh/dm 3

Li-MnO2 (Li-Mn, "CR")

Heat-treated manganese dioxide

Lithium perchlorate in propylene carbonate and dimethoxyethane

3 V

3.7 V

280

580

Li-SOCl2

Thionyl chloride

Lithium tetrachloroaluminate in thionyl chloride

3.5 V

3.65 V

290

670

Li-SOCl2,BrCl, Li-BCX

Thionyl chloride with bromine chloride

Lithium tetrachloroaluminate in thionyl chloride

3.7-3.8 V

3.9 V

350

770

Li-SO2Cl2

Sulfuryl chloride

 

3.7

3.95

330

720

Li-SO2

Sulfur dioxide on teflon-bonded carbon

Lithium bromide in sulfur dioxide with small amount of acetonitrile

2.85 V

3.0 V

250

400

Li-(CF)x ("BR")

Carbon monofluoride

Lithium tetrafluoroborate in propylene carbonate, dimethoxyethane, and/or gamma-butyrolactone

2.8 V

3.1 V

360

680

Li-I2

Iodine

solid organic charge transfer complex (eg. poly-2-vinylpyridine, P2VP)

2.8 V

3.1 V

 

 

Li-Ag2CrO4

Silver chromate

Lithium perchlorate solution

3.1/2.6 V

3.45 V

 

 

Li-Ag2V4O11, Li-SVO, Li-CSVO

Silver oxide+vanadium pentoxide (SVO)

lithium hexafluorophosphate or lithium hexafluoroarsenate in propylene carbonate with dimethoxyethane

 

 

 

 

Li-CuO

Copper(II) oxide

Lithium Perchlorate dissolved in Dioxolane

1.5 V

2.4 V

 

 

Li-Cu4O(PO4)2

Copper oxyphosphate

 

 

 

 

 

Li-CuS

Copper sulfide

 

1.5 V

 

 

 

Li-PbCuS

Lead sulfide and copper sulfide

 

1.5 V

2.2 V

 

 

Li-FeS

Iron sulfide

Propylene carbonate, dioxolane, dimethoxyethane

1.5-1.2 V

 

 

 

Li-FeS2

Iron disulfide

Propylene carbonate, dioxolane, dimethoxyethane

1.6-1.4 V

1.8 V

 

 

Li-Bi2Pb2O5

Lead bismuthate

 

1.5 V

1.8 V

 

 

Li-Bi2O3

Bismuth trioxide

 

1.5 V

2.04 V

 

 

Li-V2O5

Vanadium pentoxide

 

3.3/2.4 V

3.4 V

120/260

300/660

Li-CoO2

Cobalt dioxide

 

 

 

 

 

Li-CuCl2

Copper chloride

 

 

 

 

 

Li/Al-MnO2

Manganese dioxide

 

 

 

 

 

Li/Al-V2O5

Vanadium pentoxide

 

 

 

 

 

Li-ion

carbon

liquid

 

 

 

 

Li-poly

polymer

solid

 

 

 

 

Lithium-ion battery - With a very good power-to-weight ratio, this is often found in high-end laptop computers and cell phones (rechargeable).


Lead-acid battery- Lead-acid chemistry is used in automobiles, the electrodes are made of lead and lead-oxide with a strong acidic electrolyte (rechargeable).



Nickel-cadmium battery - The electrodes are nickel-hydroxide and cadmium, with potassium-hydroxide as the electrolyte (rechargeable). These batteries are commonly abbreviated NiCd and pronounced, "nye-cad".  NiCd batteries are known for there use in toys such as RC cars and power tools.

Dendritic shorting

NiCd batteries, when not used regularly, tend to develop dendriteswhich are thin, conductive crystals which may penetrate the separator membrane between electrodes. This leads to internal short circuits and premature failure, long before the 800-1000 charge/discharge cycle life claimed by most vendors. Sometimes, applying a brief, high-current charging pulse to individual cells can clear these dendrites, but they will typically reform within a few days or even hours. Cells in this state have reached the end of their useful life and should be replaced. Many battery guides, circulating on the Internet and online auctions, promise to restore dead cells using the above principle, but achieve very short-term results at best.


Nickel-metal hydride battery - This battery is rapidly replacing nickel-cadmium because it does not suffer from the memory effect that nickel-cadmiums do (rechargeable).


Zinc-air battery - This battery is lightweight and rechargeable.


Zinc-mercury oxide battery - This is often used in hearing-aids.


Silver-zinc battery - This is used in aeronautical applications because the power-to-weight ratio is good.


References


Nickel-cadmium battery From Wikipedia, the free encyclopedia



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