ARC studies of the reaction between Li 0FePO 4 and LiPF 6 or LiBOB EC/DEC electrolytes

Abstract

Accelerating Rate Calorimetry (ARC) has been used to study the reaction between Li 0FePO 4 having an average particle size of 3, 7 or 15 μm with EC/DEC solvent, 1.0 M LiPF 6 EC/DEC or 0.8 M lithium bis(oxalato)borate (LiBOB) EC/DEC electrolyte. LiFePO 4 electrode material was charged to 3.8 V vs. Li metal to produce Li 0FePO 4 before analysis. In EC/DEC solvent, all the three Li 0FePO 4 samples show high thermal stability and their ARC onset temperature is higher than 300 °C. As the particle size of Li 0FePO 4 increases from 3–7 to 15 μm, the self-heating rate (SHR) with EC/DEC solvent at the same temperature becomes slightly lower. With the addition of LiPF 6 to EC/DEC, self-heating exotherms begin at approximately 190 °C for all the three Li 0FePO 4 samples, independent of particle size. LiBOB-based electrolyte shows higher thermal stability than LiPF 6-based electrolytes for all the three Li 0FePO 4 samples. Self-heating exotherms for the three Li 0FePO 4 samples in 0.8 M LiBOB EC/DEC begin at about 240 °C.