Operando Investigations of the Interfacial Electrochemical Kinetics of Metallic Lithium Anodes via Temperature-Dependent Electrochemical Impedance Spectroscopy

Abstract

One of the major hurdles in the utilization of metallic lithium anodes is understanding the Li+ transfer kinetics through the solid electrolyte interface (SEI) in addition to Li oxidation. Electrochemical impedance spectroscopy (EIS) combined with temperature variation provides deeper comprehension and reveals kinetic parameters of individual processes separately. In this study, we report temperature-dependent EIS analysis of metallic Li anodes to shed light on the kinetics of anodic/interfacial processes at different states of charge and wide temperature ranges (−25 to 75 °C), utilizing lithium thionyl chloride (Li/SOCl2) and lithium manganese dioxide (Li/MnO2) primary batteries as model systems. We found in both batteries that the impedance of the SEI processes is highly temperature-dependent with non-Arrhenius behavior at temperatures greater than 35 °C. Conversely, the kinetics of the anodic process showed small temperature dependence that is explained by the Arrhenius equation throughout the temperature range studied. The results provide a deeper understanding of the underlying processes separately in metallic Li anodes under operando and real-time conditions.

Morphology-Dependent Investigation of Li-ion Insertion into Single Crystal Hematite α-Fe2O3 Nanostructures

“…EIS analysis of Li-ion insertion process in metal oxide nanostructured electrodes is not straightforward due to the high capacitive behavior at equilibrium and the low impedance values of the accompanying charge transfer reactions . In our study, the utilization of Li metal as a reference and counter electrode will result in a relatively high impedance response compared to metal oxide electrodes, which appear at the high frequency range. − The impedance spectrum of the assembled cells will have contributions from both Li and α-Fe 2 O 3 electrodes. The Nyquist plot of the impedance response of α-Fe 2 O 3 |Li for all of the morphologies is shown in Figure c.…”

Phase-Dependent Properties of Manganese Oxides and Applications in Electrovoltaics

“…The ease of ionic diffusion hinges on the interactions between diffusing ions and the host atoms. Trajectory analysis indicated slower diffusion at lower temperatures, attributed to the stronger bonding of Li with host atoms. − It appears that the interaction is enhanced with an increase in temperature, which activates the diffusion process to produce faster diffusion. Specifically, in the case of Mn 2 O 3 , the diffusion coefficient is found to be increased from 4.26 × 10 –10 to 11.4 × 10 –9 m 2 /s with an increase in temperature from 600 to 700 K. On the other hand, in the case of Mn 3 O 4 , the diffusion coefficient appeared to have significantly increased from 3.86 × 10 –10 to 4.0 × 10 –9 m 2 s –1 with an increase in temperature from 500 to 700 K. These materials exhibited a higher diffusion coefficient when compared to commercially available graphite having the value as 4.43 × 10 –9 to 5.24 × 10 –10 cm 2 s –1 …”

Highly Active Cobalt–Copper–Selenide Electrocatalysts for Solar-Driven Oxygen Evolution Reaction: An Electrochemical Activation Energy Aspect

“…The diameter of semicircle indicates the charge transfer resistance. 33,34 The diameter of CoCu(OH) 2 and CoCuSe was 0.7 and 0.2 Ω, indicating that CoCuSe had faster kinetics than CoCu(OH) 2 . Furthermore, to quantitatively analyze the number of active sites for OER, turnover frequency (TOF) was calculated.…”

“…The Tafel slope of 120 mV/dec suggests that the decomposition reaction of H 2 O into OH – and H + by the first electron-transfer is the RDS, while a Tafel slope of 30 mV/dec indicates that the second electron transfer stage is the RDS. , All samples exhibited values close to 60 mV/dec, signifying the involvement of an OH – intermediate coverage stage following the initial electron-transfer stage. , Nyquist plots of CoCu­(OH) 2 and CoCuSe were measured to investigate the charge transfer resistance ( R ct ) for the OER, as shown in Figure c. The diameter of semicircle indicates the charge transfer resistance. , The diameter of CoCu­(OH) 2 and CoCuSe was 0.7 and 0.2 Ω, indicating that CoCuSe had faster kinetics than CoCu­(OH) 2 . Furthermore, to quantitatively analyze the number of active sites for OER, turnover frequency (TOF) was calculated. , Figure S6 shows the higher value of 0.004 s –1 (CoCuSe) than 0.001 s –1 (CoCu­(OH) 2 ) at an overpotential of 300 mV.…”