PVDF-HFP/PVP-based miscible blend electrolyte for fast-charging lithium metal batteries

Abstract

Polymer electrolytes, with their excellent mechanical properties, processability, and electrochemical stability, are gaining attention for their potential in lithium metal batteries. This study introduces a solid-state polymer electrolyte synthesized through a supramolecular approach, utilizing poly(vinylidene fluoride hexafluorophosphate) (PVDF-HFP) and polyvinylpyrrolidone (PVP) in conjunction with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. The F-containing segments in PVDF-HFP establish hydrogen bonds with the carbonyl groups in PVP, resulting in a cross-linked supramolecular network that facilitates rapid Li-ion conduction in polymer electrolytes. The developed electrolyte delivers an impressive ionic conductivity of 2.84 × 10–4 S cm-1 and a high Li-ion transference number of ∼0.45. The electrolyte film is electrochemically stable up to ∼4.53 V. Notably, symmetric Li

Li cells exhibit stable cycling for over 1500 cycles (1 mA cm-2), and an excellent critical current density of 6 mA cm-2 is observed, demonstrating the compatibility of optimized polymer electrolytes with lithium metal anodes. Furthermore, Li

LiFePO4 full-cell delivers a ∼70 mAh g-1 capacity with >99 % retention after 200 cycles at 5C. This novel multi-pathway blend of fast lithium-conducting polymers enhances safety and energy density, and its robust performance has significant potential for widespread implementation in solid-state lithium metal batteries. © 2025 Elsevier Ltd