Error Analysis for Transport Properties of Lithium-Ion Battery Electrolytes
Authors: Sivasengaran Ashvini , Landesfeind Johannes 
Published: February 2024

Accurate determination of electrolyte transport properties in lithium-ion batteries (LIBs) is pivotal for understanding battery performance and optimizing their design. Electrolyte transport properties, encompassing ionic conductivity, diffusion coefficients, and transference numbers, are critical parameters that influence charge and discharge rates, ion mobility, and energy efficiency.[1,2] However, experimental measurements are inevitably accompanied by uncertainties stemming from experimental conditions, instrument calibration, and data analysis methods. Error propagation in electrolyte transport properties has substantial ramifications for battery research and development. Inaccurate measurements can lead to flawed conclusions about battery behavior and hinder the design of optimal electrolyte formulations.[3]

Based on the literature, measurements of concentration cells for the determination of electrolyte properties were conducted at different temperatures and concentrations to study its impact on transport properties, and the Gaussian error propagation method was used to analyze the data. The concentration cell experiment is essential to determine the transport factor a.

[4] The equation to determine the transport factor is shown in Figure 1a and the exemplary results are represented in Figure 1b. The results show that the error bars are significantly higher at certain concentration pairs.
The main aim of this research is to identify the sources that contribute to the prominent difference in the error bars across different concentrations and temperatures. It also discusses the significance of systematic errors, which arise due to calibration issues or instrumental biases, and random errors stemming from variations in experimental conditions.[5] Recognizing the nature of these errors is critical for accurate interpretation of experimental data. To determine the electrolyte transport properties and the corresponding error or uncertainty, experimental datasets from the literatureare studied and repeated in our laboratories.

References

[1] Boz. B, et al. J. Electrochem. Soc. 168, 90501 (2021)
[2] Valøen. L.O, Reimers. J.N. J. Electrochem. Soc. 152, A882 (2005)
[3] Taylor. J, et al. Journal of Energy Storage. 24, 100761 (2019)
[4] Landesfeind. J, Ebner. M, Eldiven. A, Wood. V and Gasteiger .H.A. J. Electrochem. Soc. 165, A469 (2018).
[5] Singh. A, Chaturvedi. P. J. Resonance. 26, 853-861 (2021)
[6] Landesfeind. J, Gasteiger. H.A. J. Electrochem. Soc. 166(14), A3079-A3097 (2019)
[Figure captions]
Figure 1 (a) Equation to determine transport factor aWhere Ucc
represents the concentration cell potential, c0

+ Δc and c0
-Δc represent the different cell concentrations whereas F, R, and T represent Faraday constant, ideal gas constant, and temperature respectively. (b) Concentration potentials Ucc

(averaged over 3 min) measured in pouch concentration cells with LiPF6 EC: DMC (1:1, w:w) at varying concentrations for temperatures ranging from −10°C to +50°C. Reprinted from Ref 6[6]

Figure 1