Potentially Confusing: Potentials in Electrochemistry
Potentially Confusing: Potentials in Electrochemistry
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DOI：
10.1021/acsenergylett.0c02443
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发表时间：
2021-01-08
影响因子：
22
通讯作者：
Kempler, Paul A.
中科院分区：
文献类型：
--
作者：
Boettcher, Shannon W.;Oener, Sebastian Z.;Kempler, Paul A.
无势是系统做功能力的量化。一个简单的例子来自力学：通过举起重物，其势能增加。当重物下落时，势能转化为动能。将电势的概念应用于电化学系统可能会令人惊讶地感到困惑。1− 4表1显示了电化学中使用的一些“电势”及其不同单位。首先，让我们考虑用电压表测量给定系统的电压。模拟电压表的工作原理是：通过校准电阻和线圈通入小电流，产生小磁场，从而使固定磁铁上的指针偏转。通过电阻器的电流与电压成比例，电阻器会导致指针偏转。然而，该电压不是系统的电势差。电势E是电场E沿沿着从参考点（通常在离系统无限远的距离处）到给定位置的路径的线积分：
Apotential quantifies the capacity of a system to do work. A simple example is from mechanics: by lifting a weight, its potential energy increases. When the weight is dropped, that potential energy is converted into kinetic energy. Applying the concept of potential to electrochemical systems can be surprisingly confusing. 1− 4 Table 1 shows some “potentials” used in electrochemistry and their different units. 5To start, let us consider a voltage measured with a voltmeter for a given system. Analog voltmeters operate by passing a small current through a calibrated resistor and wire coil, generating a small magnetic field, and thus deflecting a needle attached to a fixed magnet. The current passed through the resistor, which causes needle deflection, is proportional to the voltage. This voltage, however, is not the electric potential difference of the system. Electric potential ϕ is the line integral of the electric field E⃗ along a path from a reference point (often at infinite distance from the system) to a given position: