Understanding the Effect of Binder Ratio on the Electrochemical and Mechanical Properties of Flexible Electrodes

Abstract

Binders are essential in electrodes because they bond the active materials, conductive materials, and current collectors, ensuring the stability of the electrode microstructure and stable ionic and electron kinetics. In this study, exploiting the thermoplastic properties of polyvinylidene fluoride (PVDF), we fabricated ultra-flexible electrodes through the thermally induced phase separation (TIPS) process. Because PVDF is an electrical insulator and does not participate in the electrochemical reaction, four different binder ratios were investigated, revealing that an increase in PVDF ratio led to a decrease in capacity as a result of increased ionic and electronic resistance. Conversely, the tensile strain improved with higher PVDF ratios. Overall, the findings highlight a trade-off between electrochemical performance and mechanical properties, suggesting that a PVDF ratio below 20 wt% is optimal for flexible electrodes fabricated by TIPS. This research provides valuable insights into the effects of binders on the performance of flexible electrodes.

Keywords: Flexible electrodes, binders, thermally induced phase separation