3D PAN/LLZTO nanofibers reinforced composited polymer electrolyte for high-performance solid-state lithium metal batteries

Solid-state lithium metal batteries (SSLMBs) utilizing polymer electrolytes are regarded as highly promising for enhancing energy density and addressing safety concerns. However, their widespread applications are constrained by low ionic conductivity and inadequate mechanical properties. To overcome these limitations, this work introduces a flexible PEO/PAN/LLZTO composite solid electrolyte (PPL) fabricated via sequential electrospinning and hot-pressing technique. The PAN/LLZTO nanofibrous backbone establishes rapid Li⁺ transport pathways and significantly improve the mechanical integrity of the composite. Consequently, the PPL electrolyte achieved a remarkable ionic conductivity of 6.46 × 10⁻⁴ S cm⁻¹ alongside an impressive tensile strength of 8.79 MPa. Crucially, the spontaneous formation of inorganic LiF and Li₃N compounds at the electrolyte/Li interface promotes uniform Li⁺ deposition, enhances interfacial wettability, and effectively suppresses dendrite growth, thereby preventing short circuits. This superior interfacial stability is evidenced by symmetric cells operating stably for over 7000 h at 0.1 mA cm⁻²/0.1 mAh cm⁻². Furthermore, the full cells delivered a discharge specific capacity of 163.2 mAh g⁻¹ at 0.1 C and demonstrated exceptional cycling stability, retaining 79.6 % capacity after 800 cycles at 1.0 C.