In-situ X-ray Study of Carbon Coated LiFePO4 for Li-ion Battery in Different State of Charge

This paper is focused on the structural characterization of commercially exploited carbon coated LiFePO4 cathode material in different state of charge. The material was measured inside of modified ECC-Opto-Std cell and X-ray characterization was performed using Rigaku Miniflex 600 HR diffractometer. The study compare two approaches used for characterization of electrodes in different state of charge: a) Fast galvanostatic mode with potential limitation typically used in the ex-situ characterizations and b) Operando measurement at slow galvanostatic charging (0.1 C). Lattice parameters and volume changes were evaluated by Rietveld refinement and results indicate that carbon coating of particles does not have any influence on the volume changes of materials. We found the full compliance of lattice parameters changes and therefore also volume changes with those reported for pure LFP material in other reported studies.