Fig. 6

EIS data at different temperatures and SoCs, and the distribution of high-frequency resistance R₀. (a) The EIS curves shrink as temperature increases. Across SOC, there is little variation except for EIS of cells at 5 °C which show significant variation. EIS data for A13 and A37 are shown in red boxes to indicate that they are the two outlier cells. (b) Histogram of R₀ at 20% SoC shows a large spread around the average R₀ for all temperatures. (c) Histogram of R₀ at 50% SoC with a high frequency of R₀ concentrated near the average. (d) Histogram of R₀ at 80% SoC with a right-skewed distribution.