Electrochemical Impedance Spectroscopy Characterization of Sodium-Ion Batteries with Different Operating States

Electrochemical impedance spectroscopy (EIS) is vital for understanding electrochemical processes at interfaces. By spanning a wide frequency range, EIS elucidates cell dynamics, aiding in parameter identification and dynamic analysis. Sodium-ion batteries (SIBs) present a promising alternative for sustainable and cost-effective energy storage. Investigating SIBs’ EIS characteristics across diverse environments is crucial for optimizing their performance. In this study, we examined the EIS profiles of SIBs under varying ambient temperatures and state of charge (SOC) conditions. Our findings reveal distinct EIS regions influenced by both operating temperature and SOC. Remarkably, the high-frequency impedance spectra of SIBs exhibit less sensitivity to SOC variations at constant temperatures. These insights offer valuable guidance for enhancing SIB performance under different operating conditions.