alkaline battery

{{See also|History of the battery}}

File:Thomas Edison's nickel–iron batteries.jpg manufactured under the "Exide" brand, originally developed in 1901 by Thomas Edison, use a potassium hydroxide electrolyte.]]

Batteries with alkaline (rather than acid) electrolyte were first developed by Waldemar Jungner in 1899, and, working independently, Thomas Edison in 1901. The modern alkaline dry battery, using the zinc/manganese dioxide chemistry, was invented by the Canadian engineer Lewis Urry in the 1950s in Canada before he started working for Union Carbide's Eveready Battery division in Cleveland, OH, building on earlier work by Edison.{{Cite web|url=http://www.science.ca/scientists/scientistprofile.php?pID=277|title = Science.ca : Lew Urry}}{{cite web|last1=Baird|first1=Gabriel|title=Thomas Edison provided Lew Urry spark of idea for better alkaline battery: Greater Cleveland Innovations|url=http://blog.cleveland.com/metro/2011/08/thomas_edison_provided_spark_f.html|website=cleveland.com|access-date=November 17, 2014|date=August 3, 2011}} On October 9, 1957, Urry, Karl Kordesch, and P. A. Marsal filed US patent (2,960,558) for the alkaline battery. It was granted in 1960 and was assigned to the Union Carbide Corporation.[http://www.freepatentsonline.com/2960558.pdf US Patent 2960558] {{in lang|en}}

When alkaline batteries were introduced in the late 1960s, their zinc electrodes (in common with the then ubiquitous carbon-zinc cells) had a surface film of mercury amalgam. Its purpose was to control electrolytic action on impurities in the zinc; that unwanted electrolytic action would reduce shelf life and promote leakage. When reductions in mercury content were mandated by various legislatures, it became necessary to greatly improve the purity and consistency of the zinc.{{harvc |last= McComsey |first= Dennis W. |year= 2002 |c= Chapter 8: Zinc-Carbon Batteries (LeClanché and Zinc-Chloride Cell Systems |in1= Linden |in2= Reddy |p= [https://archive.org/details/handbookofbatter0000unse/page/n195/ 8-3] }}

In an alkaline battery, the negative electrode is zinc and the positive electrode is manganese dioxide (MnO₂). The alkaline electrolyte of potassium hydroxide (KOH) is not consumed during the reaction (it is regenerated), only the zinc and MnO₂ are consumed during discharge. The concentration of alkaline electrolyte of potassium hydroxide remains constant, as there are equal amounts of OH⁻ anions consumed and produced in the two half-reactions occurring at the electrodes.

The two half-reactions are:

• Anode (oxidation reaction), negatively charged electrode because accepting {{e-}} from the reductant in the cell:
  {{block indent|1= {{chem2|Zn(s) + 2OH(-)(aq) -> Zn(OH)2(s) + 2e(-) -> ZnO(s) + H2O(l) + 2e(-)}} {{Space|20}} (E°_ox = {{val|+1.28|u=V}}) }}
• Cathode (reduction reaction), positively charged electrode because giving {{e-}} to the oxidizer in the cell:
  {{block indent|1= {{chem2|2MnO2(s) + 2H2O(l) + 2e(-) -> 2MnO(OH)(s) + 2OH(-)(aq)}} {{Space|8}} {{harvc |last1= Scarr |first1= Robert F. |last2= Hunter |first2= James C. |last3= Slezak |first3= Philip J. |year= 2002 |c= Chapter 10: Alkaline–Mangangese Dioxide Batteries |in1= Linden |in2= Reddy |p=[https://archive.org/details/handbookofbatter0000unse/page/n259/ 10-6]}}}}

The overall reaction (sum of anodic and cathodic reactions) is:

{{block indent|1= Zn(s) + 2MnO₂(s) + H₂O(l) ↔ ZnO(s) + 2MnO(OH)(s) {{Space|26}} (E°_cell = E°_ox + E°_red = nominally {{val|+1.5|u=V}}) }}

File:Button cells and 9v cells (3).png. Two {{val|9|u=V}} batteries were added as a size comparison. Enlarge to see the size code markings.]]

The capacity of an alkaline battery is strongly dependent on the load. An AA-sized alkaline battery might have an effective capacity of {{val|3000|u=mAh}} at low drain, but at a load of {{val|1|u=ampere}}, which is common for digital cameras, the capacity could be as little as {{val|700|u=mAh}}."... the capacity of a battery generally decreases with increasing discharge current." {{harvc |last= Linden |first= David |year= 2002 |anchor-year= 2002a |c= Chapter 3: Factors Affecting Battery Performance |in1= Linden |in2= Reddy |p= [https://archive.org/details/handbookofbatter0000unse/page/n83/ 3-5]}} The voltage of the battery declines steadily during use, so the total usable capacity depends on the cutoff voltage of the application.

The nominal voltage of a fresh alkaline cell as established by manufacturer standards is {{val|1.5|u=V}}. The {{em|actual}} zero-load voltage of a new alkaline battery ranges from {{val|1.50|to|1.65|u=V}}, depending on the purity of the manganese dioxide used and the contents of zinc oxide in the electrolyte. The voltage delivered to a load decreases as the current drawn increases and as the cell discharges. A cell is considered fully discharged when the voltage drops to about {{val|0.9|u=V}}.{{harvc |last= Linden |first= David |year= 2002 |anchor-year= 2002b |c= Chapter 7: Primary Batteries – Introduction |in1= Linden |in2= Reddy |p= [https://archive.org/details/handbookofbatter0000unse/page/n183/ 7-12]}} Cells connected in series produce a voltage equal to the sum of the voltages of each cell (e.g., three cells generate about 4.5 V when new).

The amount of electrical current an alkaline battery can deliver is roughly proportional to its physical size. This is a result of decreasing internal resistance as the internal surface area of the cell increases. A rule of thumb is that an AA alkaline battery can deliver {{val|700|u=mA}} without any significant heating. Larger cells, such as C and D cells, can deliver more current. Applications requiring currents of several amperes such as powerful portable audio equipment require D-sized cells to handle the increased load.

In comparison, Lithium-ion and Ni-MH batteries can handle {{val|2|u=amperes}} with ease on the standard AA size.{{cite web |title=Discharge tests of Alkaline AA batteries 100mA to 2A |url=https://www.powerstream.com/AA-tests.htm |access-date=2024-03-29 |website=PowerStream}}

File:Alkaline-battery-english.svg

Alkaline batteries are manufactured in standard cylindrical forms interchangeable with zinc–carbon batteries, and in button forms. Several individual cells may be interconnected to form a true "battery", such as the 9-volt PP3-size battery.

A cylindrical cell is contained in a drawn stainless steel can, which is the cathode connection. The positive electrode mixture is a compressed paste of manganese dioxide with carbon powder added for increased conductivity. The paste may be pressed into the can or deposited as pre-molded rings. The hollow center of the cathode is lined with a separator, which prevents contact of the electrode materials and short-circuiting of the cell. The separator is made of a non-woven layer of cellulose or a synthetic polymer. The separator must conduct ions and remain stable in the highly alkaline electrolyte solution.{{Cite patent|number=US6783893B2|title=Alkaline battery|gdate=2004-08-31|invent1=Bowden|invent2=Brandt|invent3=Christian|invent4=Jiang|inventor1-first=William L.|inventor2-first=Klaus|inventor3-first=Paul A.|inventor4-first=Zhiping|url=https://patents.google.com/patent/US6783893B2/en}}

The negative electrode is composed of a dispersion of zinc powder in a gel containing the potassium hydroxide electrolyte. The zinc powder provides more surface area for chemical reactions to take place, compared to a metal can. This lowers the internal resistance of the cell. To prevent gassing of the cell at the end of its life, more manganese dioxide is used than required to react with all the zinc. Also, a plastic-made gasket is usually added to increase leakage resistance.{{Cite patent|number=US20100248019A1|title=Battery gasket and alkaline battery using the same|gdate=2010-09-30|invent1=Matsuhisa|invent2=Kato|inventor1-first=Ichiro|inventor2-first=Susumu|url=https://patents.google.com/patent/US20100248019A1/en}}

The cell is then wrapped in aluminium foil, a plastic film, or rarely, cardboard, which acts as a final layer of leak protection as well as providing a surface on which logos and labels can be printed.{{Cite patent|number=CN1688040A|title=Packaging structure of alkali battery and packaging method of alkali battery|gdate=2005-10-26|invent1=纪柏全|url=https://patents.google.com/patent/CN1688040A/en}}

When describing AAA, AA, C, sub-C and D size cells, the negative electrode is connected to the flat end, and the positive terminal is the end with the raised button. This is usually reversed in button cells, with the flat-ended cylindrical can being the positive terminal.

{{Main|Rechargeable alkaline battery}}

Some alkaline batteries are designed to be recharged a few times, and are described as rechargeable alkaline batteries. Attempts to recharge standard alkaline batteries may cause rupture, or the leaking of hazardous liquids that corrode the equipment. However, it is reported that standard alkaline batteries can often be recharged a few times (typically not more than ten), albeit with reduced capacity after each charge; chargers are available commercially. The UK consumer organisation Which? reported that it tested two such chargers with Energizer alkaline batteries, finding that battery capacity dropped on average to 10% of its original value, with huge variations, after two cycles (without stating how depleted they were before recharging) after recharging them two times.{{cite web |url=https://www.which.co.uk/reviews/rechargeable-batteries/article/battery-chargers-what-you-need-to-know |title=Battery Chargers - What You Need To Know |website=Which?|date=February 2016 |author=Ryan Shaw |access-date= May 20, 2019}}

In 2017 Gautam G. Yadav published papers reporting that alkaline batteries made by interleaving the interlayers with copper ions could be recharged for over 6,000 cycles due to the theoretical second electron capacity of manganese dioxide.{{cite journal|last1=Yadav|first1=G.G.|year=2017|title=Regenerable Cu-intercalated MnO2 layered cathode for highly cyclable energy dense batteries|journal=Nature Communications|volume=8|pages=14424|bibcode=2017NatCo...814424Y|doi=10.1038/ncomms14424|pmid=28262697|pmc=5343464}}{{cite journal|last1=Yadav|first1=Gautam|date=2017|title=A conversion-based highly energy dense Cu2+ intercalated Bi-birnessite/Zn alkaline battery|journal=Journal of Materials Chemistry A|volume=5|issue=30|page=15845|doi=10.1039/C7TA05347A}} The energy density of these rechargeable batteries with copper intercalated manganese dioxide is reported to be over {{val|160|u=Wh/L}}, the best among the aqueous-based chemistries. It could be capable of energy densities comparable to lithium-ion (at least {{val|250|u=Wh/L}}) if zinc utilization in the batteries were improved.

File:Alkaline Battery Leakage Inside a Product.png

Alkaline batteries are prone to leaking potassium hydroxide, a caustic agent that can cause respiratory, eye and skin irritation.This alkali particularly attacks aluminium, a common material for flashlights, which can be damaged by leaking alkaline batteries. The risk of this can be reduced by storing batteries in a dry place and at room temperature. Damage from leakage is mitigated by removing batteries when storing devices. Applying reverse current (such as by recharging disposable-grade cells, or by mixing batteries of different types or state of charge in the same device) can increase the risk of leakage.{{cn|date=June 2023}}

All batteries gradually self-discharge (whether installed in a device or not) and dead batteries eventually leak. Extremely high temperatures can also cause batteries to rupture and leak (such as in a car during summer) as well as decrease the shelf life of the battery.

The reason for leaks is that as batteries discharge{{snd}}either through usage or gradual self-discharge{{snd}}the chemistry of the cells changes and some hydrogen gas is generated. This out-gassing increases pressure in the battery. Eventually, the excess pressure either ruptures the insulating seals at the end of the battery, or the outer metal canister, or both. In addition, as the battery ages, its steel outer canister may gradually corrode or rust, which can further contribute to containment failure.

Once a leak has formed due to corrosion of the outer steel shell, potassium hydroxide absorbs carbon dioxide from the air to form a feathery crystalline structure of potassium carbonate that grows and spreads out from the battery over time, following along metal electrodes to circuit boards where it commences oxidation of copper tracks and other components, leading to permanent circuitry damage.

The leaking crystalline growths can also emerge from seams around battery covers to form a furry coating outside the device, that corrodes any objects in contact with the leaking device.

Since alkaline batteries were made with less mercury beginning in 1996, alkaline batteries are allowed to be disposed of as regular domestic waste in some locations. However, older alkaline batteries with mercury, and the remaining other heavy metals and corrosive chemicals in all batteries (new and old), still present problems for disposal—especially in landfills.{{cite web|last=Environmental Services Department|title=Battery Recycling|url=http://www.sandiego.gov/environmental-services/ep/hazardous/battrecycle.shtml|publisher=City of San Diego|access-date=September 5, 2012}}{{cite web|last=Raw Materials Company |title=Frequently Asked Questions |url=http://www.rawmaterials.com/faq/ |access-date=September 5, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20121006054936/http://www.rawmaterials.com/faq/ |archive-date=October 6, 2012 }} There is also the issue of simplifying the disposal of batteries by excluding them all from domestic waste, so that the most toxic batteries are diverted from general waste streams.

Disposal varies by jurisdiction. For example, the state of California considers all batteries as hazardous waste when discarded, and has banned the disposal of batteries in domestic waste.{{cite web|title=Batteries|url=http://www.calrecycle.ca.gov/ReduceWaste/Batteries/|work=Waste Prevention Information Exchange of ion due to graphite |publisher=California Department of Resources Recycling and Recovery (CalRecycle)|access-date=September 5, 2012}} In Europe, battery disposal is controlled by the WEEE Directive and Battery Directive regulations, and as such alkaline batteries must not be thrown in with domestic waste. In the EU, most stores that sell batteries are required by law to accept old batteries for recycling.

The disposable battery market grows at a rate of 5.5% every year.{{Cite web |title=Disposable Batteries Market Trends, Size, Share & Forecast {{!}} 2032 |url=https://www.skyquestt.com/report/disposable-batteries-market |access-date=2025-01-28 |website=www.skyquestt.com |language=en}} In the past, used batteries ended up at landfill sites, but in 2004, disposal of alkaline batteries at landfill sites was forbidden by an EU regulation.https://www.europarl.europa.eu/doceo/document/TA-5-2004-0304_EN.pdf In 2006, the EU committed to recycling 45% of all batteries by 2016.{{Citation |title=Directive 2006/66/EC of the European Parliament and of the Council of 6 September 2006 on batteries and accumulators and waste batteries and accumulators and repealing Directive 91/157/EEC (Text with EEA relevance) |date=2006-09-06 |volume=266 |url=https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32006L0066 |access-date=2025-01-28 |language=en}} In 2023, a new regulation set a target of 63% by 2027 and 73% by 2036.{{Citation |title=Regulation (EU) 2023/1542 of the European Parliament and of the Council of 12 July 2023 concerning batteries and waste batteries, amending Directive 2008/98/EC and Regulation (EU) 2019/1020 and repealing Directive 2006/66/EC (Text with EEA relevance) |date=2024-07-18 |url=https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02023R1542-20240718 |access-date=2025-01-28 |language=en}}

In the US, only one state, California, requires all alkaline batteries to be recycled. Vermont also has a statewide alkaline battery collection program.{{Cite web | url=https://www.duracell.com/en-us/technology/battery-care-use-and-disposal/ | title=Battery Care, Use and Disposal {{pipe}} Duracell Batteries}} In other US states, individuals can purchase battery recycling kits used to ship batteries to recyclers. Some stores such as IKEA also collect alkaline batteries for recycling. However, some chain stores that advertise battery recycling (such as Best Buy) accept rechargeable batteries only, and generally do not accept alkaline batteries.{{Cite news|url=https://recyclenation.com/2014/03/recycle-alkaline-batteries/|title=How to Recycle Alkaline Batteries|last=RecycleNation|date=March 18, 2014|work=RecycleNation|access-date=June 9, 2018|language=en-US}}

For recycling, the metals from crushed alkaline batteries are mechanically separated, and the waste black mass is treated chemically to separate zinc, manganese dioxide and potassium hydroxide.{{Cite journal |last=Andak |first=Bayram |last2=Özduğan |first2=Erhan |last3=Türdü |first3=Selçuk |last4=Bulutcu |first4=A. Nusret |date=2019-10-01 |title=Recovery of zinc and manganese from spent zinc-carbon and alkaline battery mixtures via selective leaching and crystallization processes |url=https://www.sciencedirect.com/science/article/abs/pii/S2213343719304956 |journal=Journal of Environmental Chemical Engineering |volume=7 |issue=5 |pages=103372 |doi=10.1016/j.jece.2019.103372 |issn=2213-3437}}

{{div col|colwidth=22em}}

• History of the battery
• Battery nomenclature
• Lewis Urry
• Oxyride battery
• Rechargeable battery
• Rechargeable alkaline battery
• List of battery sizes
• List of battery types
• Battery recycling
• Battery holder
• Battery types
• Edison–Lalande cell (an early alkaline primary battery)
• Comparison of battery types

{{div col end}}

{{Reflist|group=note}}

{{Reflist|2}}

• {{cite book |editor-last1= Linden |editor-first1= David III |editor-last2= Reddy |editor-first2= Thomas B. |title= Handbook of Batteries |date=2002 |edition= 3rd |publisher= McGraw-Hill |location= New York |isbn= 978-0-07-135978-8 |url-access= registration |url= https://archive.org/details/handbookofbatter0000unse/}}

{{Commons category|Alkaline batteries}}

• [https://web.archive.org/web/20060312193002/http://www.alliedelec.com/Images/Products/Datasheets/BM/DURACELL/Duracell_Power-Products_7370520.pdf Alkaline Material Safety Data for Duracell Alkaline Batteries] (PDF)
• [http://micro.magnet.fsu.edu/electromag/electricity/batteries/alkaline.html Alkaline Batteries]
• [http://www.batteryholders.org/alkaline_batteries.shtml Brand Neutral Alkaline Battery Specifications Based on ANSI Standards]
• [http://www.batteryholders.org/battery%20testing%20and%20compliance.shtml Overview of Battery Standards and Testing]

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