Interface Diagnostics Platform for Thin-Film Solid-State Batteries

Electrochemical measurements were done using a potentiostat (BioLogic, SP-300) with electrical feedthrough connections inside an argon-filled glovebox, using a probe station with micromanipulators in a two-electrode configuration, in which the Copper contact was both the counter and reference electrodes, and the aluminum contact side was the working electrode for all the tested devices. Potentiostatic Electrochemical Impedance Spectroscopy (PEIS) was used for evaluation of impedance profiles for the diagnostic test devices and the SSBs. A sinusoidal voltage signal with 10 mV amplitude was applied as a perturbation about each device’s initial Open-Circuit Voltage (OCV). For some of the devices, an impedance spectrum was obtained at multiple voltage steps, from 0 V to 3.6 V (vs. Cu), with an increment of 180 mV. A wait time of 5 seconds was used after incrementing the voltage before each EIS measurement at the incremented voltage, and the total time for a complete measurement under this voltage window was 1.5 hours. The frequency of the input signal varied from 250 kHz to 250 mHz (30 points per decade), and the total impedance was recorded at every measured datapoint. The collected impedances of the devices were then fitted using Z-fit, from the Biologic EC-lab software, for circuit element parameter estimation. For each tested device, an appropriate electric circuit model was designed to associate the electric parameters to the physics of the devices during operation. The Simplex+Monte-Carlo method in Z-Fit was used to minimize the fit.