Highly Ion-Conductive 3D Hybrid Solid Polymer Electrolyte Using Al-Doped Li7La3Zr2O12 Embedded Electrospun 3D Nanowebs for Ambient-Temperature All-Solid Lithium Polymer Batteries

Abstract

Solid polymer electrolytes have garnered significant attention for lithium batteries because of their flexibility and safety. However, poor ionic conductivity, lithium dendrite formation, and high impedance hinder their practical application. In this study, a thin, flexible, 3D hybrid solid electrolyte (3DHSE) is prepared by in situ thermal cross-linking polymerization with electrospun 3D nanowebs. The 3DHSE comprises Al-doped Li₇La₃Zr₂O₁₂ (ALLZO) embedded in electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nonwoven 3D nanowebs and an in situ cross-linked polyethylene oxide (PEO)-based solid polymer electrolyte. The 3DHSE exhibits high tensile strength (6.55 MPa), a strain of 40.28%, enhanced ionic conductivity (7.86 × 10⁻⁴ S cm⁻¹), and a superior lithium-ion transference number (0.76) to that of the PVDF-HFP-based solid polymer electrolyte (PSPE). This enables highly stable lithium plating/stripping cycling for over 900 h at 25 °C with a current density of 0.2 mA cm⁻². The LiNi_0.8Mn_0.1Co_0.1O₂ (NCM811)/3DHSE/Li cell has a higher capacity (140.56 mAh g⁻¹ at 0.1 C) than the NCM811/PSPE/Li cell (124.88 mAh g⁻¹ at 0.1 C) at 25 °C. The 3DHSE enhances mechanical properties, stabilizes interfacial contact, improves ion transport, prevents NCM811 cracking, and significantly boosts cycling performance. This study highlights the potential of the 3DHSE as a candidate for advanced lithium polymer battery technology.