Fluoridation of D-A Ambipolar Polymers to Accelerate Ion Migration toward High-Performance Symmetric Dual-Ion Energy Storage Devices.

Dual-ion electrochemical energy storage devices have attracted much attention due to their cost effectiveness and high operating voltage. Electrochemical properties such as the specific capacity of dual-ion energy storage devices are closely related to ion migration. However, the ion migration of dual-ion energy storage devices is slow, especially the cation migration, resulting in limited discharge capacity and poor rate performance. In this study, fluorinated and nonfluorinated ambipolar conductive polymers were prepared as electrode materials. The effects of fluorination on aggregation and solvent were studied as well as its role in improving ion migration. The results show that fluorination can increase the force of fluorination on the solvent, reduce the level of binding of the solvent to the ion, and regulate the aggregation state. Compared with the unfluorinated polymer of PEPOPE, the ion migration and electrochemical kinetics of PEPFEP were significantly improved, and the PEPFPE (71 F/cm 3 ) has a higher negative specific capacity than PEPOPE (24 F/cm 3 ) at a current density of 5 A/cm 3 .