@article{Pei2024, 
author = {Shanpeng Pei and Zhiyong Zhang and Xiuli Zhang and Yan Liu and Xiang Han and Linshan Luo and Pengfei Su and Chaofei Lan and Wei Huang and Ziqi Zhang and Ming-Sheng Wang and Songyan Chen},
title = {Evolutionary mechanism and frequency response of graphite electrode at extreme temperatures},
year = {2024},
journal = {Nano Research},
volume = {17},
number = {8},
pages = {7283-7289},
keywords = {frequency response, graphite electrode, extreme temperatures, evolutionary mechanism, solid electrolyte interphase (SEI) film},
url = {https://www.sciopen.com/article/10.1007/s12274-024-6741-z},
doi = {10.1007/s12274-024-6741-z},
abstract = {The battery management system is employed to monitor the external temperature of the lithium-ion battery in order to detect any potential overheating. However, this outside–in detection method often suffers from a lag and is therefore unable to accurately predict the battery’s real-time state. Herein, an inside–out frequency response approach is used to accurately monitor the battery’s state at various temperatures in real-time and correlate it with the solid electrolyte interphase (SEI) evolution of the graphite electrode. The SEI evolution at temperatures of −15, 25, 60, and 90 °C exhibits certain regular characteristics with temperature change. At a temperature of −15 °C, the Li+-solvent interaction of lithium-ion slowed down, resulting in a significant reduction in performance. At 25 °C, a LiF-rich inorganic SEI was identified as forming, which facilitated lithium-ion transportation. However, high temperatures would induce decomposition of lithium hexafluorophosphate (LiPF6) and lithium-ion electrolyte. At the extreme temperature of 90 °C, the SEI would be organic-rich, and LixPyFz, a decomposition product of lithium salts, was further oxidized to LixPOyFz, which led to a surge in the charge-transfer resistance at SEI (Rsei) and a reduction in Coulombic efficiency (CE). This changing relationship can be recorded in real time from the inside out by electrochemical impedance spectroscopy (EIS) testing. This provides a new theoretical basis for the structural evolution of lithium-ion batteries and the regular characterization of EIS.}
}