An In Situ Polymerized Solid‐State Electrolyte for Uniform Lithium Deposition via the Piezoelectric Effects

Abstract Solid‐state lithium metal batteries (SLMBs) have broad application prospects due to their inherently high energy density and safety. Among solid‐state electrolytes (SEs), in situ polymerized solid‐state electrolytes have the advantages of intimate interfacial contact and significant reduction in interface resistance, but they can still suffer from uncontrolled growth of lithium dendrites that compromises the long‐term stability and cyclability of the batteries. Here, a PDOL@ZnO/PVDF‐HFP SE consisting of a poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) fiber separator modified with zinc oxide (ZnO) nanowires is reported as a skeleton and in situ polymerized poly (1,3‐dioxolane) (PDOL) as the filler. The piezoelectrically generated electric field by the extrusion of ZnO nanowires during Li plating reduces localized Li + concentration and promotes uniform Li + flux, effectively inhibiting the growth of lithium dendrites. As a result, LiFePO 4 /Li cell based on the PDOL@ZnO/PVDF‐HFP SE shows long and stable cycle life at 30 °C with a reversible capacity of 144.0 mAh g −1 for 600 cycles at 0.2 C and 91.3% capacity retention. Remarkably, LiFePO 4 /Li pouch cells can be stably cycled for 200 cycles. The proposed in situ polymerized solid‐state electrolyte with piezoelectric effects opens new perspectives to guide the practical application of high‐performance solid‐state batteries.