High Precision Coulometry


The method of high precision coulometry was first introduced to the scientific community by Dr. Jeff Dahn’s lab at Dalhousie University in 2010. Novonix’s founding members have been involved in this project since inception and have a thorough understanding of the requirements of the equipment, benefits of the technique and analysis of the data. At the time there were no commercially available systems that met the specifications to make meaningful measurements of the coulombic efficiency of cells to the level of accuracy needed to compare high performance cells and therefore custom equipment was built in the lab to meet these requirements.

Precise measurements of the coulombic efficiency of a cell using the proper equipment has been shown to have enormous benefits to battery R&D projects, allowing researchers to characterize lifetime and evaluate the impact of small changes to battery design on long-term performance in short-term experiments. With this expertise, Novonix was established to develop battery testing systems specifically catered to precision measurements of coulombic efficiency. Novonix’s high precision charger systems have been shown to measure the coulombic efficiency of cells to typically less than 10 ppm precision and 50 ppm accuracy. Novonix offers both testing services and equipment sales to help customers get the most out of their use of high precision coulometry techniques.

Many recent journal publications from Dr. Dahn's and other's research groups have been centered around the use of High Precision Coulometry as a tool in evaluating lifetime performance of Li-ion cells and evaluating the impact of electrolyte additives in short-term experiments that accurately represent the long-term performance.

The above figure shows how precise measurements of the coulombic efficiency can predict the lifetime of cells that show almost no capacity loss until failure. This work is described more in Burns et al. J. Electrochem. Soc., 160, A1451 (2013).

The above figure shows how the coulombic efficiency can also predict the long term performance of cells that show gradual capacity loss with cycling.