Facilely construction of multistage channel in PVDF-HFP for high ionic conductivity and prominent anti-lithium dendrites

Abstract

Safety concerns such as lithium dendrite growth, leakage and volatilization regularly plague conventional liquid lithium metal batteries. However, solid polymer electrolytes can mitigate these issues due to their chemical and electrochemical stability. In this paper, we show that the construction of porous structures gives PVDF-HFP based polymers excellent solution retention, quick Li+ transport channels, and ultra-long Li-symmetric cycle stability. PVDF-HFP based electrolyte membrane with porous structure exhibits excellent electrolyte retention (129.5 %) and superior ionic conductivity (2.4 × 10-3 S cm−1 at 20 ℃). In addition, Lithium-symmetric half battery uses the DPH250 porous electrolyte film to stably last more than 2000 h during the lithium plating/stripping process. DI regulation of PVDF-HFP electrolyte membrane is beneficial to achieve uniform lithium deposition, and better solve the interface problems existing in solid state batteries. LiFePO4/DPH250-LiPF6/Li batteries exhibit stable cycling performance and reversible specific discharge capacity, suggesting a potential strategy for stabilizing lithium metal batteries.