Voltaic cell + battery in series

  • #1
Manganese
9
0
TL;DR Summary
Would connecting a battery in series with a voltaic cell accelerate the rate of the redox reaction of the cell?
Hello,
I wanted to know if connecting a battery in series with a voltaic cell would increase the rate of the redox reactions.

Let's take the simplest example of a voltaic cell constituted by a Zn/Zn2+ half-cell connected to a Cu/Cu2+ half-cell. When the circuit is closed, the Zn electrode will get corroded and will dissolve in Zn2+, while the Cu2+ ions in the other half-cell will get reduced to Cu.

What I wanted to know is, if I connect a battery in series with this voltaic cell (maintaining the same current direction), the potential difference should stack (if the Zn/Cu cell has a potential of 1.10 V, connecting a 3V battery in series should bring it to 4.10 V).

Will this potential increase somehow affect the rate of the redox reaction? Or the increase of the potential only affects the thermodynamics of the process (as in, it's just higher voltage) but the kinetics are unaffected? And also, would connecting a battery in series with this type of voltaic cell result in shorting the battery? I know they are getting discharged, but would this be happening at a fast rate or the voltaic cell acts as some sort of resistance?

I drew a sketch
voltaic cell + battery.png
 
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  • #2
In general - yes, but if the voltage gets too high you can start unwanted side reactions (like water hydrolysis).
 
  • #3
Manganese said:
I wanted to know if connecting a battery in series with a voltaic cell would increase the rate of the redox reactions.
An "electric battery" is a stack of electrochemical cells, working together, usually in series, to produce a higher voltage than a single cell. In the same sense, a "gun battery" is composed of several guns, that aim to work together.

The rate of the redox reactions can be increased only by increasing the current flowing through the cell. That can be done by reducing the circuit load resistance. That is Ohm's law.

For a fixed load resistance, having more cells in series would increase the current and the rate of reaction. Again, that is Ohm's law.

The circuit resistance includes the internal resistance of the battery. Heating the battery may reduce the battery internal resistance, and so increase the rate of reaction.
 
  • #4
Manganese said:
Will this potential increase somehow affect the rate of the redox reaction?
Yes, around the 'normal' currents and voltages of the cells used.
But once it's out of the 'normal' range and boiling or electrolysis happens, it may become (very) complicated.
 

1. What happens when you connect a voltaic cell and a battery in series?

When you connect a voltaic cell and a battery in series, their voltages add up. This means the total voltage available in the circuit is the sum of the voltage from the voltaic cell and the battery. This configuration can be used to increase the overall voltage output, which is useful for powering devices that require a higher voltage than what a single cell or battery can provide.

2. How do you properly connect a voltaic cell and a battery in series?

To properly connect a voltaic cell and a battery in series, you must connect the positive terminal of the voltaic cell to the negative terminal of the battery. Then, the remaining free negative terminal of the voltaic cell and the positive terminal of the battery will be used to connect to your circuit. This ensures that the voltages of both the cell and the battery add up correctly.

3. Can connecting a voltaic cell and a battery in series damage either component?

Connecting a voltaic cell and a battery in series can potentially damage either component if their voltages or chemistries are not compatible. For instance, if a high voltage battery is connected with a lower voltage voltaic cell, the larger voltage difference might cause the voltaic cell to discharge at a higher rate than it is designed for, leading to possible overheating or leakage. Always check the specifications of both the voltaic cell and the battery to ensure compatibility.

4. What are the benefits of using a voltaic cell and a battery in series?

Using a voltaic cell and a battery in series can provide a higher voltage output than using either component alone, which is beneficial for powering devices that require higher voltages. Additionally, this setup can be used to extend the operating time of a device, as the total energy capacity (measured in watt-hours) is also increased by adding more cells or batteries in series.

5. Are there any alternatives to increasing voltage output besides connecting a voltaic cell and a battery in series?

Yes, there are alternatives to increase voltage output besides connecting a voltaic cell and a battery in series. One common method is using a DC-DC converter, which can step up the voltage from a lower voltage source to a higher voltage output as needed. Another method is to use a battery pack that is specifically designed to provide a higher voltage by connecting multiple cells in series within the pack itself.

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