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, LiFePO₄/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, LiFePO₄/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.