Work

Reconstructing Residual‐Solvent‐Involved Li + Coordination in PVDF‐HFP Polymer Electrolytes for Stable Lithium Metal Batteries

Year: 2026

Type: article

Abstract: ABSTRACT Poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP)‐based polymer electrolytes offer a combination of flexibility, mechanical robustness, and room‐temperature ion transport for lithium metal batteries. However, residual N,N‐dimethylformamide (DMF) from electrolyte fabrication readily coordinates with Li + , forming a solvent‐dominated local environment that impedes Li + migration, increases the interfacial desolvation barrier, and slows charge–transfer kinetics. Herein, we reconstruct the residual‐solvent‐involved Li + coordination environment in PVDF‐HFP polymer electrolytes by introducing 2,2,2‐trifluoroethanamide (T3AM) as a weakly coordinating molecular regulator. The electron‐withdrawing −CF 3 group weakens the Li + ‐binding affinity of T3AM, attenuating DMF‐dominated coordination and promoting TFSI − participation into the Li + coordination shell. The resulting anion‐rich Li + coordination structure facilitates both ion transport and interfacial desolvation. Consequently, the T3AM‐regulated PVDF‐HFP electrolyte delivers an ionic conductivity of 0.34 mS cm −1 , a Li + transference number of 0.55, and a critical current density of 3.4 mA cm −2 . Moreover, the regulated interfacial chemistry promotes the formation of a uniform inorganic‐rich solid electrolyte interphase, enabling stable Li||Li symmetric‐cell cycling for 1500 h and Li||NCM811 full cell with 80% capacity retention after 340 cycles at 60°C and 1C. This work highlights residual‐solvent‐involved coordination reconstruction as an effective molecular strategy for simultaneously enhancing ion transport, interfacial kinetics, and lithium‐metal stability in PVDF‐HFP polymer electrolytes.

Source: Advanced Functional Materials

DOI: 10.1002/adfm.78015