How can a potentiostat be used to study battery performance and degradation?

Batteries are systems that store electrical energy as chemical energy. A charged battery has two parts that have different potentials, which can be used to apply that potential to other devices. A current will flow, and the connected device is powered.

Electrochemical measurements can characterize batteries, for example how often they can be charged and discharged, how much charge is stored in the battery, or how the battery changes over time.

There are multiple methods for characterizing batteries, which one is applied usually depends on what parameter needs to be observed. The most common techniques are Electrochemical Impedance Spectroscopy (EIS) and Charge-Discharge curves.

Charge-discharge curves

Charge-discharge curves in their most basic form are two steps of constant current that are repeated. In the first step, a current is applied to charge the battery until a set potential is reached. Then the direction of the current is inverted to discharge the battery until a certain potential is reached. How you perform charge-discharge cycles is covered in one of our tutorial videos.

Battery researchers study, for example, how much charge is stored and drawn from the battery with each cycle to predict the battery’s lifetime. The ratio between the injected charge and extracted charge is observed to estimate the efficiency.

Electrochemical Impedance Spectroscopy

EIS can extract the contribution of different components to the overall impedance of your battery. As a result, many changes inside the battery can be monitored without opening the battery. For example, the formation of the Solid Electrolyte Interface (SEI) can be observed. For more details about EIS, we recommend the article in our knowledge base.