Versatile Spiro-Fluorene-Based Polymer Binder for Li-Ion Batteries

Conductive polymers (CPs) as binders in lithium-ion batteries (LIBs) have been proposed over the past decades. This study reports developing and characterizing a polyspirobifluorene-based CP binder for LIBs. The binder is synthesized through a simple and scalable process, and its performance as a binder for electrode materials in LIBs is evaluated. The conductivity and mechanical properties of the binder are investigated, and its compatibility with various electrode materials is assessed. The results show that the polyspirobifluorene-based binder (PSFB) exhibits excellent adhesion to electrode materials, high conductivity, and improved cycling stability, making it a promising candidate for high-performance LIBs. The presentation of the polyaromatic structure reduced the overall impedance and improved the electrical conductivity by achieving 4.7 × 10–3 S/cm from the PSFB binder. Consequently, the conductive units successfully influenced the charge carriage between the cathode interfaces with low polarization and improved the electrochemical performances, especially at higher charge/discharge rates, by 22% and 31% for cathode and anode materials, respectively. In summary, these results gave efficient insights into the rational design of binders that could benefit active materials’ practical long-term cyclability and C-rate performances.