Studies on the thermal decomposition kinetics of LiPF₆ and LiBC₄O₈

Abstract

Thermal decomposition of LiPF₆ and LiBC₄O₈ (lithium bis(oxalate)borate, abbreviated as LiBOB) were studied using TG (thermogravimetry)-DTG (derivative thermogravimetry) method with different heating rate β of 5, 10, 20 and 40°C min⁻¹ or at different constant temperature θ _C (109·80, 118·79, 148·41, 176·86°C for LiPF₆ and 278·51, 298·13, 317·65, 336·13 for LiBOB). From the non-isothermal kinetics we calculate that $n_{LiPF_6 }$ is 1·01, n _LiBOB is 1·04, $E_{LiPF_6 }$ is 91907·61 J/mol, and E _LiBOB is 205179·88 J/mol; from the isothermal kinetics we calculate that n for both LiPF6 and LiBOB are 1, E_LiPF6 is 91907·61 J/mol, E _LiBOB is 205179·88 J/mol, $\ln A_{LiPF_6 }$ is 16·89 s⁻¹, and lnA_LiBOB is 31·96 s⁻¹. The results obtained from the two ways have minor differences and can validate each other.