Multi-scale interface regulation: a strategy for function-oriented modification of PVDF-Based composite electrolytes

Polyvinylidene fluoride (PVDF)-based composite electrolytes can effectively avoid the key defects of traditional liquid electrolytes, such as flammability, volatility, and leakage after sealing failure, making them a core candidate material for advanced solid-state batteries. However, these electrolytes still face several significant challenges, such as extremely low ionic conductivity at room temperature and insufficient interface compatibility, which hinders their large-scale commercialization. The adoption of multi-scale interface regulation is an effective strategy for enhancing the comprehensive performance of materials. This is mainly achieved by precisely regulating the interfacial interactions at different scales, ranging from the nanometer level to the micrometer level and up to the macroscopic level. This paper systematically reviews the preparation methods, characterization techniques, and Li+ transport mechanisms of PVDF-based composite solid electrolytes. Meanwhile, the interface engineering at macroscale, microscale, and nanoscale is discussed in depth. At the same time, it also discusses its application in other metal batteries. Moreover, the article points out current challenges and deepens the research on the interface mechanism. In conclusion, PVDF-based composite electrolytes can demonstrate significant potential in enhancing ion conductivity and interface compatibility through multi-scale interface control strategies, providing crucial theoretical basis and technical paths for the practical application of high-safety and high-performance solid-state batteries.