Difference Between Electrode Potential and Cell Potential

Thekey differencebetween electrode potential and cell potential is that电极potential refers to the ability of an电极in a cell to get reduced or oxidized whereas cell potential is the difference between the electrode potentials of the electrodes present in anelectrochemical cell.

Electrode potential and cell potential are terms that explain the electromotive force of an electrochemical cell. Electrode potential gives the voltaic potential of a single electrode while cell potential considers the electrode potentials of both electrodes.

内容

1.Overview and Key Difference
2.What is Electrode Potential
3.What is Cell Potential
4.并排比较 - 表格形式的电极电势与电池电位
5.概括

什么是电极电位？

Electrode potential is the tendency of an electrode in an electrochemical cell to get reduced or oxidized. It is the electromotive force of a cell. There are three factors affecting the value of the electrode potential: nature of the electrode, the concentration of the ions in the electrolytic solution and temperature. For any electrochemical cell, the total potential is the sum of electrode potentials of the two electrodes. We can denote the electrode potential as E. However, we cannot measure the electrode potential in isolation. It has to be measured in a reaction with some other electrode.

Moreover, the electrode potential depends on the concentrations of the electrodes, the temperature of the electrochemical cell, and also the pressure (if the cell contains gas electrodes). Generally, the electrode potentials are measured with respect to a standard electrode.

The typical standard electrode is the hydrogen electrode and its electrode potential is taken as zero. In addition, we must use standard thermodynamic conditions in order when measuring the potentials; otherwise, we cannot get the exact potential value since the electrode potential depends on the temperature, pressure, etc. Here, the standard thermodynamic conditions include measuring against a hydrogen electrode, an electrolytic solution having a concentration of 1 mol/L, pressure of 1 atm, and a temperature of 25°C.

What is Cell Potential?

Cell potential refers to the total voltaic potential of an electrochemical cell having two electrodes. Here, the electrochemical cells should have two separate half-reactions that take place parallel to each other and then, the cell potential is as follows:

E_cell= oxidation potential + reduction potential

Therefore, the cell potential is the sum of thecathode电极potential and theanode电极potential. A real voltaic cell differs from standard conditions. Therefore, we need to adjust the experimental value to get the standard value. It is as follows:

E_cell= E⁰_cell- （RT/NF）LNQ

Where E_cellis the experimental cell potential, E⁰_cell是标准电池电位，r是通用常数，t是温度，n是半反应交换的电子的摩尔，f是法拉第常数，q是热力学反应商。

What is the Difference Between Electrode Potential and Cell Potential?

电极电位和电池电位之间的关键差异是电势是指电池在细胞中减少或氧化的电极的能力，而细胞电位是电化学电池中存在的电极的电极电位之间的差异。Therefore, electrode potential gives the voltaic potential of a single electrode while cell potential considers both electrodes.

Moreover, another significant difference between electrode potential and cell potential is that it is impossible to measure the electrode potential because it is a relative value, but cell potential can easily be measured because we need to find the difference in electrode potentials, which are relative values.

概括– Electrode Potential vs Cell Potential

在电化学下，关于电化学细胞的电极电位和细胞电位将讨论。电极电位和电池电位之间的关键差异是电势是指电池在细胞中减少或氧化的电极的能力，而细胞电位是电化学电池中存在的电极的电极电位之间的差异。

Reference:

1. “Standard Electrode Potentials.”高物理学,Available here.

Image Courtesy:

1. “Galvanic Cell” By Gringer – File:Galvanische Zelle.png, by Tinux(CC BY-SA 3.0)viaCommons Wikimedia