High-performance LiFePO4/C electrode with polytetrafluoroethylene as an aqueous-based binder

• We have applied an aqueous-based polymer, PTFE, as a binder for LiFePO4/C electrodes.
• The slurry prepared with PTFE binder shows better viscosity than that with PVDF.
• The LiFePO4/C electrodes with PTFE show better electrochemical performance.
• Electrodes with PTFE have been optimized by controlling the moisture content.

An environmental-friendly and low-cost polymer, polytetrafluoroethylene (PTFE) has been applied as an aqueous-based binder for the fabrication of LiFePO4/C electrode. The electrode with PTFE has been compared to the electrode with the conventional binder, polyvinylidene fluoride (PVDF) via Rheology test, X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and electrochemical tests. The Rheology test indicates that the viscosity of the slurry prepared with PTFE as a binder is better than that prepared with PVDF. The electrochemical measurements demonstrate that the electrode with PTFE binder displays a higher discharge capacity of 161.1 mAh g−1 compared to the electrode with PVDF binder, which shows a discharge capacity of 150.7 mAh g−1. The EIS analysis indicates the LiFePO4/C electrode with PTFE binder shows a higher ionic conductivity and a smaller increasing in charge transfer rate compared to the LiFePO4/C electrode with PVDF binder. In addition, the electrodes applying the aqueous-based binder have been optimized by controlling the moisture content in the electrodes. The electrochemical enhancement of these electrodes can be achieved by controlling the vacuum drying temperature and time during the preparation of the electrodes.