Fluorinated Deep Eutectic Polymer Electrolytes with Hydrogen Bonds-Rich Networks: Realizing Targeted Management of...

The exploration of Li⁺ transport mechanism in the bulk and the interface holds the key to achieving rapid Li⁺ transport and desolvation kinetics. However, little is still known about that in gel polymer electrolytes enriched with hydrogen bond networks. Here, fluorinated gel-deep eutectic solvated (FG-DES) polymer electrolytes are fabricated for exploring the aforementioned mechanism by spectroscopy and molecular dynamics (MD) simulation. The observation provides an insight into the formation of [Li⁺···solvent] primary solvation sheath and the migration of the sheath along the polymer backbone in a fast and oriented manner through dissociation and complexation of the hydrogen bonds between solvents and polymer skeletons. Furthermore, the polymer backbone exerts a targeted management by pulling and anchoring effect on protonic solvent molecules, accelerating the desolvation process and reducing side reactions. Based on this, the capacity retention of the assembled LFP||Li is 94.7% after 600 cycles at 1 C, and the retention of NCM622||Li is 87.1% after 200 cycles, which demonstrats its excellent compatibility in lithium metal cells. This work offers a design basis for achieving rapid Li⁺ mobility and deposition in a hydrogen bonds-rich environment.