Analyses of the Calendaring Process for Performance Optimization of Li-Ion Battery Cathode

Olivine structure LiFePO4 (LFP) was synthesized via solid state processes, using Li2CO3, NH4H2PO4, and FeC2O4·H2O and C12H22O11 as precursor materials. The effects of calendaring are analyzed in terms of electrochemical performance, cycle life, surface morphology, and ac impedance analysis. The resulting LFP electrode was divided into calendared and uncalendared samples. Under electrochemical impedance testing, the calendared and uncalendared electrodes exhibited a charge transfer resistance of 157.8 Ω and 182.4 Ω, respectively. The calendared electrode also exhibited a higher discharge capacity of about 130 mAh/g at 0.1C compared to a discharge capacity of 120 mAh/g at 0.1C for the uncalendared electrode.