Low-frequency Inductive Loop and Its Origin in the Impedance Spectrum of a Graphite Anode

Graphite is a well-known anode material for commercial lithium-ion batteries, and its physical electrochemical properties have been studied extensively. However, the origin of an inductive loop observed in low-frequency region Nyquist complex plane impedance spectrum graphite has widely debated attributed to contrasting reasons. This paper investigates at various states charge (SoCs) using three-electrode galvanostatic Electrochemical Impedance Spectroscopy (EIS) further explores response electrolyte as function frequency. The EIS measurement displayed almost entire SoCs, irrespective solid interphase (SEI) age. To study this spectrum, we fabricated pouch cell with NMC electrodes estimated frequency range from 1 MHz 0.05 Hz. low frequencies exhibited behavior, indicating significant role characteristic spectrum.