Fluorinated polyimide with sulfonyl group as a novel binder for high-performance lithium-ion batteries

A kind of fluorinated polyimide carrying sulfonyl groups (SFPI) as a novel binder is synthesized, which possesses excellent thermal stability, solubility, and mechanical properties. The cells with SFPI binder exhibit lower impedance and polarization compared with the cells adding the conventional PVDF binder. The electrochemical test results showed that the SFPI binder–based LiFePO4 (LFP) electrode exhibits 134.1 mAh g−1 after 100 cycles and about 94.1% of the capacity is maintained. Especially, the overcharge safety of lithium-ion batteries during overcharge state is significantly improved by incorporating a SFPI binder.