在电池测试中使用三电极电池

电池通常有两个电极：阳极和阴极。在充电和放电周期中，离子通过分离器到达任一电极，并在此过程中释放能量。 

电池测试单元可以建立在包括第三个电极的基础上。这就是所谓的参考电极（RE）。参考电极允许对电池性能进行更多的分析，因为它将阳极和阴极的测试结果解耦。

在研究电池材料时，参考电极（RE）的使用使研究人员能够测量和区分电池的每个组成部分对其整体性能的贡献。三电极实验有助于确定哪个电极（阳极或阴极）在长期测试中限制电池的性能。重要的是确定每个电极在各种测试条件下对电池退化的贡献，而不是盲目地用一个或两个电极进行实验。

为什么这很重要？

大多数 所有 electrochemical experiments and battery tests provide greater understanding of the cell when the anode and cathode results can be decoupled through use of a reference electrode.  This extends to what are traditionally considered “industrial” applications as well.  The dynamic charge-discharge profiles and fast charge simulations associated with commercial devices and electric vehicles can draw unique performance from a battery compared to low-rate constant current cycling.

Three-electrode testing is also beneficial for evaluating battery safety.  Minter and Juarez-Robles highlight how fast-charging, which is a highly sought characteristic for electric vehicles, creates a great need to detect and monitor lithium plating occurring on a cell anode.  [Minter RD, Juarez-Robles D, et al 2018 J Vis Exp., (135):57735.]  This can best be achieved using a three-electrode cell during testing.

One fundamental goal of battery research is to develop cells that are long-lasting.  This is especially important for electric vehicle and grid storage applications where the commercial cells and battery packs must last thousands of cycles and up to 10 years.  Three-electrode testing allows researchers to identify the limiting factor in their cell to focus attention where improvement is needed most.

在不同的测试情况下如何使用参比电极

• During HPPC test, which are common for 电动汽车应用，使用参比电极揭示了电极的极化。

• Performing EIS交流阻抗 shows the decoupled impedance from anode and cathode individually when a three-electrode cell is utilized.

• The individual contribution of anode and cathode is revealed when demonstrating lithium loss due to SEI growth as a dominant aging mechanism.

• 差异容量分析可以揭示阳极和阴极电压曲线的变化，以及它们是如何单独导致电池退化的。

创建稳定和可靠的三电极电池的障碍

Comparing results from a new three-electrode experiment to other published results needs to keep as many variables consistent as possible, such as electrode size, material amount, cell uniformity, etc., or else attempt to normalize results.  This is a principal reason why traditional cell types are modified to incorporate a reference electrode as “homemade” cell, so results are easier to compare with minimal normalization.  Researchers wish to demonstrate and compare their results to existing two-electrode data of the same cell type (cylindrical, pouch, coin).  However, since most battery material work is conducted using coincells, this is the natural choice for three-electrode experiments to compare the new results with the vast amount of tradition two-electrode data in publication.  The new experimental data will decouple the anode and cathode and provide new insights.

Suggestion

A wide range of three-electrode cell configurations—such as Swagelok-style cells, split-cell designs, and PAT cells—are available and commonly used for electrochemical studies. However, it is important to recognize that these systems also have limitations. They can be expensive, complex to assemble, and challenging to scale for practical applications. Additionally, data obtained from such specialized cells must be carefully normalized when compared with conventional battery formats (e.g., coin, cylindrical, or pouch cells). Therefore, these considerations should be thoroughly evaluated when selecting an appropriate testing configuration for your specific research or development objectives.