Silver-oxide battery

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Silver-oxide battery
Silver oxide batteries.jpg
Silver oxide cells
Specific energy130 Wh/kg[1]
Energy density500 Wh/L[1]
Specific powerHigh
Charge/discharge efficiencyN/A
Time durabilityHigh
Cycle durabilityN/A
Nominal cell voltage1.55V

A silver-oxide battery (IEC code: S) is a primary cell with a very high energy-to-weight ratio. They are available in small sizes as button cells, where the amount of silver used is minimal and not a significant contributor to the product cost.

Silver-oxide primary batteries account for 30% of all primary battery sales in Japan (64 out of 212 million in February 2020).[2]


A silver-oxide battery uses silver(I) oxide as the positive electrode (cathode), zinc as the negative electrode (anode), plus an alkaline electrolyte, usually sodium hydroxide (NaOH) or potassium hydroxide (KOH). The silver is reduced at the cathode from Ag(I) to Ag, and the zinc is oxidized from Zn to Zn(II).

The half-cell reaction at the negative plate:


The reaction in the electrolyte:


The half-cell reaction at the positive plate:


Overall reaction:


Overall reaction (anhydrous form):

Mercury content[edit]

Several sizes of button and coin cells, some of which are silver-oxide

Until recently, all silver-oxide batteries contained up to 0.2% mercury.[citation needed] The mercury was incorporated into the zinc anode to inhibit corrosion in the alkaline environment. Sony started producing the first silver-oxide batteries without added mercury in 2004.[3]

See also[edit]


  1. ^ a b "ProCell Silver Oxide battery chemistry". Duracell. Archived from the original on 2009-12-20. Retrieved 2009-04-21.
  2. ^ "Monthly Battery Sales Statistics". MoETI. May 2020. Retrieved 2020-08-07.
  3. ^ World’s First Environmentally Friendly Mercury Free Silver Oxide Batter. September 29, 2004.

External links[edit]