Talk:Zinc–carbon battery

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This thing is totally messed up! When I finish my finals I'll clean it up. Kr5t 22:37, 21 May 2006 (UTC)[reply]

If you have a chance, could you also re-write the intro? When the article was first created,[1] the text was simply copied from the World Book Encyclopedia. Most of that text is still there. It's not a lot, but it'd be better if this were entirely written by our editors, rather than stolen from another encyclopedia. -Will Beback 20:18, 8 June 2006 (UTC)[reply]

It appears that people have confused zinc-carbon batteries, a type of dry cell battery, with dry cells. Besides zinc-carbon batteries, there are other types of dry cells, the most common being batteries. For this reason, I am posting the content from that dry cell here in case any of it can be worked into the this (zinc-carbon battery) article. I added an equals sign to allow of the sections so that it would only take up one section in this talk page. Also, I made the image into a link to the image. -- Kjkolb 07:40, 4 August 2006 (UTC)[reply]

Image:Dry_cell.png

A dry cell, also known as a Leclanché cell or a zinc-carbon battery, is a form of primary electrochemical cell that supplies electrical energy at small currents. Dry cells range in size between large flashlight batteries and tiny watch batteries but the basic construction is the same: a zinc cup lined with paper filled with an electrolyte paste with a graphite (carbon) rod in the center terminated with a metal cathode at the top.

Because it was compact and reliable, the dry cell was commonly used to power portable electronic devices such as radios and flashlights until it was replaced by alkaline cells which solve many of the dry cell's shortcomings. Everyday use of the term “battery” usually is a reference to either the dry or the alkaline cell.

Like all electrochemical cells, the dry cell gets its electrical energy from an internal chemical reaction which takes the form of two half-cell reactions. The electrolyte in the cell consists of ammonium chloride, manganese(IV) oxide, finely granulated carbon and an inert filler which is usually starch. The ammonia from the ammonium ions forms the complex ion Zn(NH₃)₄²⁺ with the Zn²⁺ preventing buildup of Zn ions which would result in reduction of the potential of the cell.

In standard electrochemical cell notation the dry cell looks like:

Zn(s)|ZnCl₂(aq), NH₄Cl(aq)|MnO(OH)(s)|MnO₂(s)|graphite

With a cell potential of approximately 1.5 volts and the following half-cell reactions

At the anode (-):

Zn(s) → Zn²⁺(aq) + 2 e^-

followed by Zn²⁺(aq) + 2 NH₃(g) → [Zn(NH₃)₂]²⁺(aq)

At the cathode (+):

MnO₂(s) + H₂O(l) + e^- → MnO(OH)(s) + OH^-(aq)

followed by NH₄⁺(aq) + OH^-(aq) → H₂O(l) +NH₃(g)

The reaction is further complicated by the production of two gaseous products in the reduction of ammonium ions:

2 NH₄⁺(aq) + 2 e^- → 2 NH₃(g) + H₂(g)

These products must be absorbed within the cell if gas pressure is not to build up. Two further reactions within the paste electrolyte absorb the gas. Zinc chloride reacts with ammonia to form solid zinc ammonium chloride and manganese dioxide reacts with hydrogen to form solid dimanganese trioxide and water.

ZnCl₂(aq) + 2 NH₃(g) → Zn(NH₃)₂Cl₂(s)

2 MnO₂(s) + H₂(g) → Mn₂O₃(s) + H₂O(l)

The cell initially produces about 1.5 volts, but this decreases as the reaction goes on because the moist paste is not completely mobile, so the electrolyte near the electrodes can be completely reacted, inhibiting further reaction, while un-reacted electrolyte is left in the body of the cell.

Dry cells have several advantages over wet cells such as a lead acid battery:

• They can be made very compact
• They do not require liquid water such as sulfuric acid (H₂SO₄), so they are more easily contained and transported and are lighter weight
• The chemicals involved are relatively safe
• Dry cells are fairly inexpensive to produce.

However, there are also several disadvantages to the dry cell:

• As a primary cell, dry cells cannot be recharged and must be discarded after their potential has dropped below a useful level.
• As mentioned earlier, the paste electrolyte is not completely mobile, so the reagents cannot be used completely.
• The zinc anode of the battery is also its outer case. As the reaction goes on, the anode is consumed and becomes thinner and thinner, until eventually the cell starts to leak. The leaked water and electrolyte make the outside of the cell sticky, and can damage the electronic device that the cell is powering.
• Shelf life is the greatest disadvantage of the dry cell, however. Even when not in use, the zinc electrode reacts with and is corroded by the electrolyte, limiting the shelf life of the cell to at most 1.5 years. Its potential decreases as well, especially in cold conditions.

Because of these shortcomings, dry cells have now been replaced by alkaline cells, which are similar to dry cells except that they use an alkaline electrolyte which the zinc electrode doesn't readily react with when energy is not being drawn from the cell.

An early dry cell was invented in 1802 by Johann Ritter.

The dry cell as we know it today was invented by Georges Leclanché in 1866. His design used a positive electrode consisting of a mixture of manganese dioxide and carbon in a porous pot. This and a zinc rod which served as the negative electrode were then immersed in an ammonium chloride solution. This became known as Leclanché's "wet" cell. Leclanché original design was prone to breakage but was improved by later engineers.

J.A. Thiebaut patented the first cell combining both the negative electrode and porous pot into a zinc cup in 1881; but Carl Gassner is credited with producing the first commercially successful dry cell in 1888 (patent 1887).

In 1909 the tungsten filament provided the impetus to use the dry cell to power the first battery-operated flashlights.

• Zinc-carbon battery (much more complicated and detailed, perhaps even clearer, explanation of chemical process inside a dry cell)
• Wet cell
• Georges Leclanché
• Galvanic cell
• Electrochemical cell

• Chemsoc Timeline, Dry Cell Battery [2]
• HyperPhysics, Batteries [3]
• University of Hawaii, The "Dry-Cell" Battery [4]

• "Georges Leclanché" biography at Corrosion Doctors
• "Johann Ritter" biography at Corrosion Doctors
• "Galvanic Battery" at Today in Science History

The main components:

1. zinc- anode
2. carbon rod- cathode
3. paste of MnO2, NH4Cl, H2O as the electrolyte
4. Porous paper- separates the paste from the Zn casing, also allows for the diffusion of ions.
5. wax seal prevents the evaporation of water.

An anonymous user made this comment on the dry cell talk page. I moved it here, since it does not apply to dry cells. The comment was modified slightly. -- Kjkolb 08:10, 4 August 2006 (UTC)[reply]

I have now edited the dry cell page to form a link and make it a bit clearer that a zinc-carbon battery is one example of a dry cell. I hope I have made this article a little clearer to readers by doing so. Also the carbon rod is not really the cathode but is merely a collector. With reference to the above comments the manganese dioxide and carbon powder acts as the cathode as stated in the original wikipedia article zinc-carbon battery! By a former physics teacher 14 50 1st November 2006 I agree: 65 years ago dry cell typically refered to a much scaled up version of the AA cell. I believe they were otherwise identical, except they had thumb nut terminals. The inside of the zinc can had a thin film of mercury to prevent local action. A thinner film of mercury meant poorer shelf life. No mercury meant the zinc carbon battery was unacceptable for any application, but I suppose they are still made in some countries, less strict about mercury. The manganes dioxide is called a depolarizer as it removes the hydrogen bubbles which otherwise partially insulate the carbon rod from the rest of the battery. New zinc carbon batteries could deliver about 15 amps briefly to a very low resistant load. Modern alkaline batteries only about 5 amps. Typical applications require 1/2 amp or less. See alkaline batteries Ccpoodle 21:40, 13 November 2007 (UTC)[reply]

I've revised the introduction and the chemistry reactions - hopefully that is now clear enough for interested readers. (I shifted to normal html for the equations as it is simpler and gives the same result.) Also included is a link to the Dry Cell page, which gives a simpler account. I added some details on the heavy duty (zinc chloride) cell, and more references. I removed all specific mention of hydrogen as (1) it isn't a significant side-reaction (2) some of the chemical equations were wrong.Ian 12:29, 16 March 2007 (UTC)[reply]

When were ordinary AA/AAA/C/D batteries first commonly sold? -69.87.203.130 (talk) 01:10, 18 June 2008 (UTC)[reply]

This article uses both. Mwongozi (talk) 08:13, 24 June 2008 (UTC)[reply]

It has been proposed in this section that Zinc–carbon battery be renamed and moved to Zinc-carbon cell. A bot will list this discussion on the requested moves current discussions subpage within an hour of this tag being placed. The discussion may be closed 7 days after being opened, if consensus has been reached (see the closing instructions). Please base arguments on article title policy, and keep discussion succinct and civil. Please use {{subst:requested move}}. Do not use {{requested move/dated}} directly. Links: current log • target log • direct move

Zinc-carbon battery → Zinc-carbon cell — The electrochemical battery is simply a pair of electrochemical cells. this article deals around how this type of cell works.— Preceding unsigned comment added by 81.245.90.148 (talk) 11:55, 9 October 2009 (UTC)[reply]

• Oppose. The present name of the article is clear, common, and accurate. The proposed name is not. This one one of a dozen renames proposed by the anon IP today, none of which should be carried out until some concensus is obtained. --Wtshymanski (talk) 14:48, 9 October 2009 (UTC)[reply]
• Strong Oppose and suggest speedy close (is that possible?). This is not what the general public would be looking for. HumphreyW (talk) 15:24, 9 October 2009 (UTC)[reply]
• Neutral: Technically, a battery is a combination of many Dry cells. However, the term in common usage, even for single cells, is "battery". Probably leave name as it stands. Jubilee��clipman 15:44, 9 October 2009 (UTC)[reply]
  • Technically you're wrong, since I have a battery in my car that has many wet cells, it's usually called a lead acid battery or the starter battery. :)
    • True. :) The general observation I made still stands, though. Jubilee♫clipman 17:38, 9 October 2009 (UTC)[reply]

76.66.197.30 (talk) 16:09, 9 October 2009 (UTC)[reply]

• Opppose WP:COMMONNAME 76.66.197.30 (talk) 16:10, 9 October 2009 (UTC)[reply]
• Oppose The term "battery" is almost always used by consumers, battery manufacturers, etc. TJ Spyke 17:30, 9 October 2009 (UTC)[reply]