Poly(vinylidene fluoride) (PVDF)-based polymer electrolytes (PEs) with good electrochemical performance and processability as well as low-cost advantage, have great potential applications in solid-state lithium (Li) metal batteries (SSLMBs). PVDF-based PEs are generally produced by employing a solution-casting approach with ,-dimethylformamide (DMF) as the solvent, accompanied by the formation of [DMF-Li] complex, which facilitates the Li-ion transport. However, the residual DMF can react continuously with lithium (Li) metal, thereby deteriorating the interface layer in the middle of the PVDF-based PEs and Li anodes. Herein, we introduce propylene carbonate (PC) into the PVDF-based PEs to regulate the solvation structure and stabilize the interface layer between the PEs and Li anodes. PC accelerates the dissociation of lithium oxalyldifluoroborate (LiODFB). Consequently, “lithium propylene dicarbonate (LPDC)‒B-O″ oligomer forms as the interfacial layer with high tenacity, homogeneity, and densification, which improves the interfacial contact and suppresses the continuous reaction between the residual DMF and Li anode. We further demonstrate that the PVDF-based PE prepared with DMF-PC mix-solvents shows improved room-temperature ionic conductivity (1.18 × 10 S/cm), enhanced stability against electrodes, and superior cycling performance in LiCoO-based SSLMBs (maintaining 84 % of the initial discharge capacity after 300 cycles).

中文翻译：

---

PVDF基电解质与锂负极之间固体电解质界面层的改性


聚偏二氟乙烯（PVDF）基聚合物电解质（PE）具有良好的电化学性能和加工性能以及低成本优势，在固态锂（Li）金属电池（SSLMB）中具有巨大的潜在应用。 PVDF基PE通常采用溶液流延法生产，以二甲基甲酰胺（DMF）为溶剂，同时形成[DMF-Li]复合物，促进锂离子传输。然而，残留的DMF会与锂（Li）金属持续反应，从而使PVDF基PE和锂阳极中间的界面层恶化。在此，我们将碳酸丙烯酯（PC）引入PVDF基PE中，以调节溶剂化结构并稳定PE和锂阳极之间的界面层。 PC 加速草酰基二氟硼酸锂 (LiODFB) 的解离。因此，“二碳酸锂丙烯（LPDC）-B-O”低聚物形成具有高韧性、均匀性和致密化的界面层，改善了界面接触并抑制了残留的DMF和Li阳极之间的连续反应。我们进一步证明，用 DMF-PC 混合溶剂制备的基于 PVDF 的 PE 在基于 LiCoO 的 SSLMB 中表现出改善的室温离子电导率 (1.18 × 10 S/cm)、增强的电极稳定性以及优异的循环性能（保持 84 300次循环后初始放电容量的%）。