Impedance characteristic region analysis of NCM and LMFP blending system
XU Xinxin
HU Qi
LIU Ziwen
HE Wei
LIU Jianhua
Abstract：A convex characteristic region occurs in the hybrid pulse power characteristic(HPPC)curve of lithium ferromanganese phosphate(LMFP)and NCM blending system,and the state of charge(SOC)interval corresponding to the characteristic region becomes wider after the charge-discharge cycle of the cell.The application of the distribution of relaxation times(DRT)method for analyzing electrochemical impedance spectroscopy(EIS),combined with the test results of the lithium ion diffusion coefficient,indicates that the characteristic regions are caused by the discharge characteristics of LMFP.After cycling,the Mn mass fraction of cathode decreases,and when the blending system is discharged from 90%SOC to 50%SOC,the diffusion polarization(Rw)and positive charge transfer impedance(Rct)gradually increase,resulting in the widening of SOC interval corresponding to the characteristic region.
Keywords：LMFPNCMHPPC curvecharacteristic region
Publication Date：2025-08-25
Online Publishing Date：2025-09-22(First online date of this platform, not the publication date of the document)
Pages：6( 287-292 )