“Peapod-like” Fiber Network: A Universal Strategy for Composite Solid Electrolytes to Inhibit Lithium Dendrite Growth in Solid-State Lithium Metal Batteries

Solid-state lithium metal batteries (SSLMBs) are a promising energy storage technology, but challenges persist including electrolyte thickness and lithium (Li) dendrite puncture. A novel three-dimensional “peapod-like” composite solid electrolyte (CSEs) with low thickness (26.8 μm), high mechanical strength, and dendrite inhibition was designed. Incorporating Li₇La₃Zr₂O₁₂ (LLZO) enhances both mechanical strength and ionic conductivity, stabilizing the CSE/Li interface and enabling Li symmetric batteries to stabilize for 3000 h. With structural advantages, the assembled LFP||Li and NCM811||Li cells exhibit excellent cycling performance. In addition, the constructed NCM811 pouch cell achieves a high gravimetric/volumetric energy density of 307.0 Wh kg^-1/677.7 Wh L^-1, which can light up LEDs under extreme conditions, demonstrating practicality and high safety. This work offers a generalized strategy for CSE design and insights into high-performance SSLMBs.