Thermal reactions of lithiated graphite anode in LiPF6-based electrolyte

Effects of Phosphorous-doping on Electrochemical Performance and Surface Chemistry of Soft Carbon Electrodes

“…The prominent exothermic peak at 312 o C for non-doped soft carbon is attributed to the exothermic decomposition reactions of the lithiated soft carbon electrode with volatile organic solvents, which result in a large heat evolution. 19,20 According to Yamaki et al, 20 the thermal reactions of lithiated graphite particles covered with a PVdF binder with an electrolyte begin at around 300 o C, because the protective effect of the PVdF binder is not sufficient at elevated temperatures. From this point of view, it is thought that the newly exposed lithiated soft carbon by swelling of the PVdF binder at elevated temperatures thermally decomposes in the presence of an electrolyte and generates a large amount of exothermic heat at temperature over 300 o C, as shown in Figure 8.…”

Quaternary Ammonium-Based Room Temperature Ionic Liquids as Components of Carbonate Electrolytes for Li-ion Batteries: Electrochemical Performance and Thermal Properties

“…10a depicts the DSC heating curves for lithiated graphite or delithiated LiMn 2 O 4 with different electrolyte compositions. For a model experiment, graphite (or LiMn 2 O 4 ) has been charged in a well-described standard 1M LiPF 6 solution in EC/ EMC (3/7, v/v) [25][26][27][28][29][30][31][32][33][34][35][36][37]. In comparison with reference IL-free electrolyte, the presence of TMPA-TFSI does not affect the thermal decomposition of SEI at lithiated graphite surface (first exothermic peak around 150 o C) but suppresses the thermal reactions between electrolyte and lithiated graphite (two consecutive peaks around 230 and 320 o C).…”

Electrochemical and thermal properties of graphite electrodes with imidazolium- and piperidinium-based ionic liquids

“…The two broad peaks between 180 and 300 • C resulted from the thermal reaction between the Ref electrolyte and lithiated graphite. Finally, a large exothermic peak at 350 • C was ascribed to the formation of a secondary SEI layer (lithium alkylcarbonates and Li 2 CO 3 ) and the thermal decomposition reactions of a PVdF binder with lithiated graphite [20]. The MPPpTFSI ionic liquid considerably reduces the exothermic heat evolution from the thermal reactions between the lithiated graphite and the electrolyte, as shown in Figs.…”

“…The thermal reactions between the hydrogen fluoride (HF) generated from LiPF 6 at about 64 • C and an evaporated EMC in a Ref electrolyte triggers the beginning of a broad exothermic peak at 80 • C, as shown in Fig. 6(a) [20]. It is probable that the broad exothermic peak between 80 and 250 • C is the result of the subsequent thermal reactions of PF 5 (g) produced from LiPF 6 decomposition and organic solvents.…”

“…It is known that the thermal decomposition of a lithiated graphite anode with an electrolyte is determined by two principal factors: one is the thermal resistibility of SEI layer formed electrochemically on the graphite electrode surface, and the other is the amount of Li + ions intercalated into the graphene layers [3][4][5]13,[21][22][23]. [20]. An exothermic peak with an onset at around 90 • C, shown in Fig.…”