Silver oxide zinc battery

Silver oxide zinc button cells

Silver oxide zinc cells (abbreviated: “silver oxide cells”) are primary cells . They are mainly sold in the form of button cells and then bear the IEC designation " SR ".

The negative pole (anode) of a silver oxide-zinc cell consists of zinc powder , which is oxidized in the course of the discharge . The positive pole (cathode) consists of silver (I) oxide , which is reduced to elemental silver when discharged . Diluted potassium hydroxide (or sodium hydroxide ) is used as the electrolyte . The nominal voltage of such a cell is about 1.55 V. In addition to zinc hydroxide, potassium zincate (K ₂ [Zn (OH) ₄ ]) is also formed through reaction with the electrolyte .

Traditional silver oxide-zinc cells can only be recharged a few tens of times. However, there are hundreds of rechargeable silver-zinc batteries from ZPower with an energy density of 338 or 272 Wh / l (depending on size).

Chemical processes

In simplified terms, the following reactions take place during discharge:

• Reduction: ${\displaystyle \mathrm {Ag_{2}O+H_{2}O+2e^{\operatorname {-} }\longrightarrow \,2Ag+2OH^{\operatorname {-} }} }$
• Oxidation: ${\displaystyle \mathrm {Zn\longrightarrow \,Zn^{2\operatorname {+} }+2e^{\operatorname {-} }} }$
• Redox: ${\displaystyle \mathrm {2Ag^{\operatorname {+} }+Zn\longrightarrow \,2Ag+Zn^{2\operatorname {+} }} }$
• Total: ${\displaystyle \mathrm {Ag_{2}O+H_{2}O+Zn\longrightarrow \,2Ag+Zn(OH)_{2}} }$

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1. ^ Paul Buckley: Opinion: Recharge your engineering batteries. EDN Network, August 25, 2008, accessed on December 12, 2017 (English): "Silver-zinc technology ['s] ... traditional short cycle life of about 20 to 25 recharge cycles has hampered its application in the consumer market." 
2. ↑ ^{a b} ZPower Size 312 Rechargeable Battery (XR41) (data sheet)
3. ↑ ZPower Silver-Zinc Rechargeable Microbatteries
4. ↑ ZPower Size 13 Rechargeable Battery (XR48) (data sheet)