An Ultrahigh Modulus Gel Electrolytes Reforming the Growing Pattern of Li Dendrites for Interfacially Stable Lithium‐Metal Batteries

Abstract Gel polymer electrolytes (GPEs) have aroused intensive attention for their moderate comprehensive performances in lithium‐metal batteries (LMBs). However, GPEs with low elastic moduli of MPa magnitude cannot mechanically regulate the Li deposition, leading to recalcitrant lithium dendrites. Herein, a porous Li₇La₃Zr₂O₁₂ (LLZO) framework (PLF) is employed as an integrated solid filler to address the intrinsic drawback of GPEs. With the incorporation of PLF, the composite GPE exhibits an ultrahigh elastic modulus of GPa magnitude, confronting Li dendrites at a mechanical level and realizing steady polarization at high current densities in Li||Li cells. Benefiting from the compatible interface with anodes, the LFP|PLF@GPE|Li cells deliver excellent rate capability and cycling performance at room temperature. Theoretical models extracted from the topology of solid fillers reveal that the PLF with unique 3D structures can effectively reinforce the gel phase of GPEs at the nanoscale via providing sufficient mechanical support from the load‐sensitive direction. Numerical models are further developed to reproduce the multiphysical procedure of dendrite propagation and give insights into predicting the failure modes of LMBs. This work quantitatively clarifies the relationship between the topology of solid fillers and the interface stability of GPEs, providing guidelines for designing mechanically reliable GPEs for LMBs.