Rechargeable lithium-ion battery (LIB) has raised intense interest and found wide application in various fields such as electronic devices, tools, and vehicles, because of its ability to provide high energy density, three times more than conventional lead acid or nickel-hydride batteries. Use of electrolyte additives is one of the most economic and effective methods for the improvement of Li-ion battery performance.

In this study, two additives, Difluoroethylene Carbonate (DFEC) and Lithium difluorophosphate (LiPF₂O₂), were Examined. DFEC was obtained by chemical synthesis route as the source additive. Several aspects related to the new additive (DFEC) have been investigated: the selection of base electrolyte solvents; the electrochemical performances based on the new additive, and th...[ Read more ]

Rechargeable lithium-ion battery (LIB) has raised intense interest and found wide application in various fields such as electronic devices, tools, and vehicles, because of its ability to provide high energy density, three times more than conventional lead acid or nickel-hydride batteries. Use of electrolyte additives is one of the most economic and effective methods for the improvement of Li-ion battery performance.

In this study, two additives, Difluoroethylene Carbonate (DFEC) and Lithium difluorophosphate (LiPF₂O₂), were Examined. DFEC was obtained by chemical synthesis route as the source additive. Several aspects related to the new additive (DFEC) have been investigated: the selection of base electrolyte solvents; the electrochemical performances based on the new additive, and the interfacial analyses of electrodes cycled in DFEC containing electrolytes.

Characteristics of DFEC and LiPF₂O₂ were examined by various approaches, including the DFT calculations and physical characterization methods, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman Spectroscopy, and the electrochemical methods including the Cyclic Voltammetry (CV), electrochemical impedance spectroscopy (EIS), charge/discharge cycling different current rates.

It was found that DFEC-containing pouch cells achieved 94% capacity retention compared to that of 89% with FEC as an additive after 800 cycles under ambient conditions. And this service performance becomes more obvious as temperature increased to 60℃, during which process DFEC retained a higher capacity of 86% compared to 75% for FEC counterparts after 300 cycles. Additionally, the addition of LiPF₂O₂ into base electrolyte can increase the discharge capacity for each pouch cell by 20 mAh as internal resistance was decreased rapidly after only 3 cycles.