Accelerating Measurement Times by Correlating Electrode/Electrolyte Interface Properties with Cycle and Calendar Lifetimes

Electrochemical performance measurements on novel battery technologies are slow and require substantial resources. For example, a common metric for assessing the cycle lifetime of a cell is by charging and discharging at a rate of one cycle every six hours (C/3) for 1000 cycles and reporting the remaining capacity after the measurement. At this rate, a single measurement takes eight months to acquire useful data. Even worse, the benchmark for an acceptable shelf-life (calendar life) is to retain 80% of the initial cell capacity through 10 years. As of now, the only reliable method for acquiring this value is to hold the cell at open circuit for the duration of the time (10 years) while performing intermittent reference performance tests. The ability to quickly screen new chemistries for LIB applications offers tremendous value for accelerating discovery. Here, I will present an electrochemical impedance technique that measures a key parameter of the solid|electrolyte interface. This method uses the Helmholtz and Gouy-Chapman-Stern models of electrochemical interfaces to approximate the ‘health’ of the anode|electrolyte interface. These measurements strongly correlate to the average Coulombic efficiency of batteries with different cell chemistries which may offer predictive power for assessing the long-term cycle and calendar lifetimes.