Anode designation in a lead acid cell

AI Thread Summary
The discussion focuses on the confusion surrounding the anode and cathode designations in lead acid cells. It clarifies that during discharge, the anode is the lead electrode, which gains electrons from sulfate ions, while the lead dioxide acts as the cathode, oxidizing and releasing electrons. The terminology can be misleading, as the roles of the electrodes reverse during charging. Participants emphasize the importance of specifying whether the context is charging or discharging to avoid confusion. Overall, the lead electrode is identified as the oxidizing electrode during discharge, while the lead dioxide is the oxidizing electrode during charging.
Silhorn
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Hi,

I am trying to determine the conventional cathode and anode designations for lead acid cells.

From what I have researched:

  • Anode is where current flows in the device, or where electrons flow out of.

  • In a secondary cell the designations for anode and cathode are based on the discharge reaction and while in the charging reaction the naming should be reversed it is misleadingly ignored.

From this the anode in a lead acid cell should be the lead electrode as that's where it gains electrons from the sulphate ions during discharge.

But if I use google images for a lead acid cell all of the images I see show the anode as the oxidation electrode where electrons would flow into.

Could someone clear this up for me?
Thanks.
 
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The anode is the positive electrode. During discharge it becomes positive and during charge a positive potential is applied, so it is still positive.
This Wiki article gives the chemistry, and at the cathode the release of electrons in the reaction can be seen. https://en.wikipedia.org/wiki/Lead–acid_battery
The anode is made of lead dioxide when charged.
 
ok so the positive electrode is the lead dioxide which oxidizes when discharging correct?

It is oxidizing because it is giving away electrons to the hydrogen ions?

Now I have been doing more research and something else needs to be cleared up for me.

At the lead electrode:
The lead gives up electrons.
The sulfate ions also attract to the lead which gives up electrons to form radical sulfate and reacts with the positive lead ions to form lead sulphate.

Is this true?
That means lead is actually the oxidizing electrode and not the lead dioxide electrode?

Sources:
https://www.ausetute.com.au/pbbattery.html
http://www.altenergy.org/renewables/lead-acid_batteries.html
(Skip to time 1:55)
 
Beware: the reactions are reversed during charging and discharging. Saying "lead gives up electrons" without clearly stating whether you refer to the charging or discharging leads tom confusion.

Silhorn said:
The sulfate ions also attract to the lead which gives up electrons to form radical sulfate and reacts with the positive lead ions to form lead sulphate.

Care to elaborate? I have serious problems trying to decode what you just wrote. I am not sure what "radical sulfate" is intended to mean.
 
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