The Effect of Poly(vinylidene difluoride-co-hexafluoropropylene)-g-poly(styrene sulfonate) Binder and Carbon Fiber Current Collector on the Electrochemical Performance of LiFePO4 Cathode for Lithium-Ion Batteries

The current investigation explores the influence of the poly(vinylidene fluoride-co-hexafluoropropylene)-graft-poly(sodium styrenesulfonate) (PVDF-HFP-g-PSSA) binder on the electrochemical performance of LiFePO4 electrodes using electrochemical measurements of cathodic half-cells. A comparison is made between the electrochemical enhancements of the brush copolymer synthesized by using the atom transfer radical polymerization (ATRP) process and the traditional PVDF binder material. Substituting conventional aluminum current collectors with carbon fiber current collectors effectively enhances the active surface area of the electrodes. The outcomes of the research illustrate that the utilization of the PVDF-HFP-g-PSSA binder leads to reduced concentration polarization and boosted intercalation kinetics, particularly at higher cycle numbers. The cathode comprising the PVDF-HFP-g-PSSA copolymer binder displays a remarkably high initial discharge capacity value of 340 mAh g–1 when subjected to a 0.1 C current density. Additionally, after 300 charge/discharge cycles, a discharge capacity value of 143 mAh g–1 is observed at 0.5 C. Furthermore, the initial capacity at 3 C is 195 mAh g–1 and reaches 160 mAh g–1 after 100 cycles. It is noteworthy that the Coulombic efficiency of this cathode is 100% even after 300 cycles. The synergistic impact of utilizing carbon fibers and sulfonated binders can enhance the potential of structural batteries over conventional lithium-ion batteries (LIBs), enabling them to be used for high-efficiency battery designs suitable for electric vehicles.