Leveraging Synergies by Combining Polytetrafluorethylene with Polyvinylidene Fluoride for Solvent-Free Graphite Anode Fabrication

Abstract

Solvent-free graphite anode is fabricated successfully with the synergistic effect of polytetrafluorethylene (PTFE) and polyvinylidene fluoride (PVDF). PTFE acts as a processing aid reagent to form a self-supporting electrode film, while PVDF acts as a functional binder when PTFE decomposes in the first lithiation process. The solvent-free graphite electrode with high loading of 15 mg cm−2 shows good stability with more than 95% capacity retention after 50 charge/discharge cycles under the current of 0.23 mA cm−2. Electrodes with extra high loading of 27 mg cm−2 (8.2 mAh cm−2) are fabricated and show good stability. Initial coulombic efficiency increases to 89% after prelithiation in the full cell with lithium iron phosphate as cathode. The capacity retention of full cells is more than 80% after 110 cycles under the current of 0.7 mA cm−2 in coin cells. The roll-to-roll production makes the procedure compatible with current commercial lithium-ion batteries production lines, exhibiting great potential for upscaling production.