High-performance pyrrolidinium-based poly(ionic liquid) binders for Li-ion and Li-air batteries

The role of binders is crucial to achieve high performance and long cycle lifes in next-generation electrodes for lithium batteries. Currently used binders in electrode configurations, such as poly(vinylidene difluoride) (PVDF) are inactive polymers that do not transport lithium ions themselves, causing restrictions for high-power applications. Thus, developing innovative binders with an affinity towards lithium mobility is important for both lithium-ion and lithium-air batteries. In this work, we present for the first time the use of PDADMA poly(ionic liquid)s with fluorinated anions (FSI, TFSI, BETI, and CFSO) as cathode binders in Li-ion and Li-air batteries. The high-voltage NMC 532 cathodes with fluorinated PDADMA binders showed improved cells performances as: capacity values, rate performance, and cycling stability in accelerating aging conditions dedicated for more environmental-friendly mobility applications. Especially, PDADMA-CFSO binder in cathodes shows a cell capacity increase of 26% at 5C (12 min charge), when compared to PVDF one. Moreover, the fluorinated PDADMA binders in cathode improve the discharge capacities in Li–O2 cells, both with liquid and solid gel polymer electrolytes. Impressively, the Coulombic efficiency improves by 146% and the cycling capacity by 70% in solid-state Li–O2 cells using PDADMA-CFSO binder in the cathode, instead of common lithiated Nafion. All in all, the proposed fluorinated PDADMA Poly(ionic liquid)s can be a highly competitive alternative to conventional binders used nowadays in Li-ion and Li-air batteries. This article presents the use of PDADMA poly(ionic liquid)s with fluorinated anions (FSI, TFSI, BETI and CFSO) as cathode binders for both Li-ion and Li-air batteries, which show improved cell performances respect to commonly used PVDF and Nafion binders in high voltage NMC and air cathodes, respectively. [Display omitted] •Pyrrolidinium-based poly(ionic liquid)s are presented as binders for Li-ion and Li-air batteries.•NMC cathodes with PDADMA-BETI and PDADMA-CFSO showed improved capacity values, compared to cathodes with PVDF binder.•PDADMA-TFSI binder in Li–O2 battery cathodes improved the discharge capacities by 50% with liquid and gel electrolytes.•PDADMA–based binders provide transition to all-solid-state battery devices due to their intrinsic ionic conductivity.