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Zinc–carbon battery

A zinc–carbon battery is a dry cell primary battery that provides direct electric current from the electrochemical reaction between zinc and manganese dioxide (MnO2). It produces a voltage of about 1.5 volts between the zinc anode, which is typically realized as a container for the battery, and a carbon rod of positive polarity, the cathode, that collects the current from the manganese dioxide electrode, giving the cell its name.

Zinc–carbon batteries of various sizes

General-purpose batteries may use an aqueous paste of ammonium chloride (NH4Cl) as electrolyte, possibly mixed with some zinc chloride solution. Heavy-duty types use a paste primarily composed of zinc chloride (ZnCl2).

Zinc–carbon batteries were the first commercial dry batteries, developed from the technology of the wet Leclanché cell. They made flashlights and other portable devices possible, because the battery functions in any orientation. They are still useful in low-drain or intermittent-use devices such as remote controls, flashlights, clocks or transistor radios. Zinc–carbon dry cells are single-use primary cells. Zinc-carbon batteries today have been mostly replaced by the more efficient and safe alkaline batteries.

Contents

Old 3 V zinc–carbon battery (around 1960), with cardboard casing

By 1876, the wet Leclanché cell was made with a compressed block of manganese dioxide. In 1886, Carl Gassner patented a "dry" version by using a zinc cup as the anode and a paste of plaster of Paris (and later, wheat flour) to jellify the electrolyte and to immobilize it.[citation needed]

In 1898, Conrad Hubert used consumer batteries manufactured by W. H. Lawrence to power what was the first flashlight, and subsequently the two formed the Eveready Battery Company. In 1900, Gassner demonstrated dry cells for portable lighting at the World's Fair in Paris. Continual improvements were made to the stability and capacity of zinc–carbon cells throughout the 20th century; by the end of the century the capacities had increased fourfold over the 1910 equivalent. Improvements include the use of purer grades of manganese dioxide, better sealing, and purer zinc for the negative electrode. Zinc-chloride cells (usually marketed as "heavy duty" batteries) use a paste primarily composed of zinc chloride, which gives a longer life and steadier voltage output compared with ammonium chloride electrolyte.[citation needed]

Side reactions due to impurities in the zinc anode increase self-discharge and corrosion of the cell. Formerly, the zinc was coated with mercury (Hg) to form an amalgam, protecting it. Given that this is an environmental hazard, current production batteries no longer use mercury. Manufacturers must now use more highly purified zinc to prevent local action and self-discharge.

As of 2011,[update] zinc–carbon batteries accounted for 20% of all portable batteries in the United Kingdom and 18% in the E.U.

The container of the zinc–carbon dry cell is a zinc can (anode). The can contains a layer of NH4Cl or ZnCl2 aqueous paste impregnating a paper layer that separates the zinc can from a mixture of powdered carbon (usually graphite powder) and manganese (IV) oxide (MnO2), which is packed around a carbon rod. Carbon is the only practical conductor material because every common metal quickly corrodes in the positive electrode in salt-based electrolyte.[citation needed]

Cross-section of a zinc–carbon battery

Early types, and low-cost cells, use a separator consisting of a layer of starch or flour. A layer of starch-coated paper is used in modern cells, which is thinner and allows more manganese dioxide to be used. Originally cells were sealed with a layer of asphalt to prevent drying out of the electrolyte; more recently a thermoplastic washer sealant is used. The carbon rod is slightly porous, which allows accumulated hydrogen gas to escape, while retaining the aqueous electrolyte. The ratio of manganese dioxide and carbon powder in the cathode paste affects the characteristics of the cell: more carbon powder lowers internal resistance, while more manganese dioxide improves storage capacity.

Flat cells are made for assembly into batteries with higher voltages, up to about 450 volts. Flat cells are stacked and the whole assembly is coated in wax to prevent electrolyte evaporation. Electrons flow from the anode to cathode through the wire of the attached device.

In a zinc–carbon dry cell, the outer zinc container is the negatively charged terminal.

Ammonia chloride electrolyte

The zinc is oxidised by the charge carrier, chloride anion (Cl) into ZnCl2, via the following half-reactions:

Anode (oxidation reaction, marked −)

Zn + 2 Cl → ZnCl2 + 2 e

Cathode (reduction reaction, marked +)

2 MnO2 + 2 NH4Cl + H2O + 2 e → Mn2O3 + 2 NH4OH + 2 Cl

Other side reactions are possible, but the overall reaction in a zinc–carbon cell can be represented as

Zn + 2 MnO2 + 2 NH4Cl + H2O → ZnCl2 + Mn2O3 + 2 NH4OH

Zinc chloride electrolyte

If zinc chloride is substituted for ammonium chloride as the electrolyte, the anode reaction remains the same:

Zn + 2 Cl → ZnCl2 + 2 e

and the cathode reaction produces zinc hydroxide and manganese(III) oxide.

2 MnO2 + ZnCl2 + H2O + 2 e → Mn2O3 + Zn(OH)2 + 2 Cl

giving the overall reaction

Zn + 2 MnO2 + H2O → Mn2O3 + Zn(OH)2

The battery has an electromotive force (e.m.f.) of about 1.5V. 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, which causes the terminal voltage to drop under load.

The zinc-chloride cell, frequently referred to as a heavy-duty, extra-heavy-duty, super-heavy-duty, or super-extra-heavy-duty battery, is an improvement on the original zinc–carbon cell, using purer chemicals and giving a longer service life and steadier voltage output as it is used and offering about twice the service life of general-purpose zinc–carbon cells, or up to four times in continuous-use or high-drain applications. This is still a fraction of the output of an alkaline cell, however.

Alkaline batteries offer up to eight times the battery life of zinc–carbon batteries, especially in continuous-use or high-drain applications.

Manufacturers recommend storage of zinc–carbon batteries at room temperature; storage at higher temperatures reduces the expected service life. Zinc–carbon batteries may be frozen without damage; manufacturers recommend that they be returned to normal room temperature before use, and that condensation on the battery jacket must be avoided. By the end of the 20th century, the storage life of zinc–carbon cells had improved fourfold over expected life in 1910.

Zinc–carbon cells have a short shelf life, as the zinc is attacked by ammonium chloride. The zinc container becomes thinner as the cell is used, because zinc metal is oxidized to zinc ions. When the zinc case thins enough, zinc chloride begins to leak out of the battery. The old dry cell is not leak-proof and becomes very sticky as the paste leaks through the holes in the zinc case. The zinc casing in the dry cell gets thinner even when the cell is not being used, because the ammonium chloride inside the battery reacts with the zinc. An "inside-out" form with a carbon cup and zinc vanes on the interior, while more leak-resistant, has not been manufactured since the 1960s.

Progressive corrosion of zinc–carbon batteries

This picture shows the zinc container of fresh batteries at (a), and discharged batteries at (b) and (c). The battery shown at (c) had a polyethylene protection film (mostly removed in the photo) to keep the zinc oxide inside the casing.

Thousands of tons of zinc–carbon batteries are discarded every year around the world and are often not recycled.

Disposal varies by jurisdiction. For example, in the U.S, the state of California considers all batteries as hazardous waste when discarded, and has banned the disposal of batteries with other domestic waste. In Europe, battery disposal is controlled by the WEEE Directive and Battery Directive regulations, and as such zinc–carbon batteries must not be thrown out with domestic waste. In the EU, most stores that sell batteries are required by law to accept old batteries for recycling.

Disassembled zinc chloride cell (similar to zinc carbon cell). 1: entire cell, 2: steel casing, 3: zinc negative electrode, 4: carbon rod, 5: positive electrode (manganese dioxide mixed with carbon powder and electrolyte), 6: paper separator, 7: polyethylene leak proof isolation, 8: sealing rings, 9: negative terminal, 10: positive terminal (originally connected to carbon rod).
  1. Linden, David; Reddy, Thomas B. (2002). "8". Handbook of batteries. McGraw-Hill. ISBN 978-0-07-135978-8.
  2. "Monthly Battery Sales Statistics". Baj.or.jp. MoETI. May 2020. Retrieved2020-08-07.
  3. INOBAT 2008 statistics. Archived March 25, 2012, at the Wayback Machine.
  4. Battery Waste Management – 2006 DEFRA.
  5. EPBA Sustainability Report, 2010.
  6. https://web.archive.org/web/20200609212007/https://www.explainthatstuff.com/batteries.html
  7. "Put a charge into your battery savings". Chicago Tribune. 2015-04-29. Retrieved2015-06-19.
  8. "Zinc Chloride Batteries". Radio Shack. Archived from the original on 2015-02-12. Retrieved2015-06-19.
  9. Eveready: Carbon Zinc Application Notes, page 13.
  10. "Batteries". Waste Prevention Information Exchange. California Department of Resources Recycling and Recovery (CalRecycle). Retrieved5 September 2012.
Wikimedia Commons has media related toZinc-carbon batteries.

Zinc–carbon battery
Zinc carbon battery Language Watch Edit A zinc carbon battery is a dry cell primary battery that provides direct electric current from the electrochemical reaction between zinc and manganese dioxide MnO2 It produces a voltage of about 1 5 volts between the zinc anode which is typically realized as a container for the battery and a carbon rod of positive polarity the cathode that collects the current from the manganese dioxide electrode giving the cell its name Zinc carbon batteries of various sizes General purpose batteries may use an aqueous paste of ammonium chloride NH4Cl as electrolyte possibly mixed with some zinc chloride solution Heavy duty types use a paste primarily composed of zinc chloride ZnCl2 Zinc carbon batteries were the first commercial dry batteries developed from the technology of the wet Leclanche cell They made flashlights and other portable devices possible because the battery functions in any orientation They are still useful in low drain or intermittent use devices such as remote controls flashlights clocks or transistor radios Zinc carbon dry cells are single use primary cells Zinc carbon batteries today have been mostly replaced by the more efficient and safe alkaline batteries Contents 1 History 2 Construction 3 Chemical reactions 3 1 Ammonia chloride electrolyte 3 2 Zinc chloride electrolyte 4 Zinc chloride heavy duty cell 5 Storage 6 Durability 7 Environmental impact 8 See also 9 References 10 External linksHistory EditSee also History of the battery Old 3 V zinc carbon battery around 1960 with cardboard casing By 1876 the wet Leclanche cell was made with a compressed block of manganese dioxide In 1886 Carl Gassner patented a dry version by using a zinc cup as the anode and a paste of plaster of Paris and later wheat flour to jellify the electrolyte and to immobilize it citation needed In 1898 Conrad Hubert used consumer batteries manufactured by W H Lawrence to power what was the first flashlight and subsequently the two formed the Eveready Battery Company In 1900 Gassner demonstrated dry cells for portable lighting at the World s Fair in Paris Continual improvements were made to the stability and capacity of zinc carbon cells throughout the 20th century by the end of the century the capacities had increased fourfold over the 1910 equivalent 1 Improvements include the use of purer grades of manganese dioxide better sealing and purer zinc for the negative electrode Zinc chloride cells usually marketed as heavy duty batteries use a paste primarily composed of zinc chloride which gives a longer life and steadier voltage output compared with ammonium chloride electrolyte citation needed Side reactions due to impurities in the zinc anode increase self discharge and corrosion of the cell Formerly the zinc was coated with mercury Hg to form an amalgam protecting it Given that this is an environmental hazard current production batteries no longer use mercury Manufacturers must now use more highly purified zinc to prevent local action and self discharge 1 As of 2011 update zinc carbon batteries accounted for 20 of all portable batteries in the United Kingdom and 18 in the E U 2 3 4 5 Construction EditThe container of the zinc carbon dry cell is a zinc can anode The can contains a layer of NH4Cl or ZnCl2 aqueous paste impregnating a paper layer that separates the zinc can from a mixture of powdered carbon usually graphite powder and manganese IV oxide MnO2 which is packed around a carbon rod Carbon is the only practical conductor material because every common metal quickly corrodes in the positive electrode in salt based electrolyte citation needed Cross section of a zinc carbon battery Early types and low cost cells use a separator consisting of a layer of starch or flour A layer of starch coated paper is used in modern cells which is thinner and allows more manganese dioxide to be used Originally cells were sealed with a layer of asphalt to prevent drying out of the electrolyte more recently a thermoplastic washer sealant is used The carbon rod is slightly porous which allows accumulated hydrogen gas to escape while retaining the aqueous electrolyte The ratio of manganese dioxide and carbon powder in the cathode paste affects the characteristics of the cell more carbon powder lowers internal resistance while more manganese dioxide improves storage capacity 1 Flat cells are made for assembly into batteries with higher voltages up to about 450 volts Flat cells are stacked and the whole assembly is coated in wax to prevent electrolyte evaporation Electrons flow from the anode to cathode through the wire of the attached device 6 Chemical reactions EditIn a zinc carbon dry cell the outer zinc container is the negatively charged terminal Ammonia chloride electrolyte Edit The zinc is oxidised by the charge carrier chloride anion Cl into ZnCl2 via the following half reactions Anode oxidation reaction marked Zn 2 Cl ZnCl2 2 e Cathode reduction reaction marked 2 MnO2 2 NH4Cl H2O 2 e Mn2O3 2 NH4OH 2 Cl Other side reactions are possible but the overall reaction in a zinc carbon cell can be represented as Zn 2 MnO2 2 NH4Cl H2O ZnCl2 Mn2O3 2 NH4OHZinc chloride electrolyte Edit If zinc chloride is substituted for ammonium chloride as the electrolyte the anode reaction remains the same Zn 2 Cl ZnCl2 2 e and the cathode reaction produces zinc hydroxide and manganese III oxide 2 MnO2 ZnCl2 H2O 2 e Mn2O3 Zn OH 2 2 Cl giving the overall reaction Zn 2 MnO2 H2O Mn2O3 Zn OH 2 The battery has an electromotive force e m f of about 1 5V 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 which causes the terminal voltage to drop under load Zinc chloride heavy duty cell EditThe zinc chloride cell frequently referred to as a heavy duty extra heavy duty super heavy duty or super extra heavy duty battery is an improvement on the original zinc carbon cell using purer chemicals and giving a longer service life and steadier voltage output as it is used and offering about twice the service life of general purpose zinc carbon cells or up to four times in continuous use or high drain applications 1 This is still a fraction of the output of an alkaline cell however Alkaline batteries 7 offer up to eight times the battery life of zinc carbon batteries 8 especially in continuous use or high drain applications 1 Storage EditManufacturers recommend storage of zinc carbon batteries at room temperature storage at higher temperatures reduces the expected service life 9 Zinc carbon batteries may be frozen without damage manufacturers recommend that they be returned to normal room temperature before use and that condensation on the battery jacket must be avoided By the end of the 20th century the storage life of zinc carbon cells had improved fourfold over expected life in 1910 1 Durability EditZinc carbon cells have a short shelf life as the zinc is attacked by ammonium chloride The zinc container becomes thinner as the cell is used because zinc metal is oxidized to zinc ions When the zinc case thins enough zinc chloride begins to leak out of the battery The old dry cell is not leak proof and becomes very sticky as the paste leaks through the holes in the zinc case The zinc casing in the dry cell gets thinner even when the cell is not being used because the ammonium chloride inside the battery reacts with the zinc An inside out form with a carbon cup and zinc vanes on the interior while more leak resistant has not been manufactured since the 1960s 1 Progressive corrosion of zinc carbon batteries This picture shows the zinc container of fresh batteries at a and discharged batteries at b and c The battery shown at c had a polyethylene protection film mostly removed in the photo to keep the zinc oxide inside the casing Environmental impact EditThousands of tons of zinc carbon batteries are discarded every year around the world and are often not recycled Disposal varies by jurisdiction For example in the U S the state of California considers all batteries as hazardous waste when discarded and has banned the disposal of batteries with other domestic waste 10 In Europe battery disposal is controlled by the WEEE Directive and Battery Directive regulations and as such zinc carbon batteries must not be thrown out with domestic waste In the EU most stores that sell batteries are required by law to accept old batteries for recycling Disassembled zinc chloride cell similar to zinc carbon cell 1 entire cell 2 steel casing 3 zinc negative electrode 4 carbon rod 5 positive electrode manganese dioxide mixed with carbon powder and electrolyte 6 paper separator 7 polyethylene leak proof isolation 8 sealing rings 9 negative terminal 10 positive terminal originally connected to carbon rod See also EditComparison of battery types List of battery sizes List of battery types Photoflash batteryReferences Edit a b c d e f g Linden David Reddy Thomas B 2002 8 Handbook of batteries McGraw Hill ISBN 978 0 07 135978 8 Monthly Battery Sales Statistics Baj or jp MoETI May 2020 Retrieved 2020 08 07 INOBAT 2008 statistics Archived March 25 2012 at the Wayback Machine Battery Waste Management 2006 DEFRA EPBA Sustainability Report 2010 https web archive org web 20200609212007 https www explainthatstuff com batteries html Put a charge into your battery savings Chicago Tribune 2015 04 29 Retrieved 2015 06 19 Zinc Chloride Batteries Radio Shack Archived from the original on 2015 02 12 Retrieved 2015 06 19 Eveready Carbon Zinc Application Notes page 13 Batteries Waste Prevention Information Exchange California Department of Resources Recycling and Recovery CalRecycle Retrieved 5 September 2012 External links EditWikimedia Commons has media related to Zinc carbon batteries Eveready Carbon Zinc Application Notes Rayovac Alkaline and Heavy Duty Application Notes Power Stream Battery Chemistry FAQs Cell Construction Power dense zinc manganese power unit as cheap as a car battery Retrieved from https en wikipedia org w index php title Zinc carbon battery amp oldid 1041110768, wikipedia, wiki, book,

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