Regulating Interfacial Li+ Transport for Dendrite-Free PVDF-Based Solid Polymer Lithium Metal Batteries: Mechanisms and Strategies.

Poly(vinylidene fluoride) (PVDF)-based solid polymer electrolytes (SPEs) are promising for lithium metal batteries because of their intrinsic safety, mechanical flexibility, and solution processability. However, their practical application is still hindered by unstable interfacial Li+ transport, which leads to nonuniform lithium deposition and dendrite growth at the PVDF/Li metal interface. This review highlights that dendrite formation in PVDF-based SPEs is fundamentally governed by the loss of spatiotemporal homogeneity in interfacial Li+ transport. By integrating classical dendrite-growth theories, we establish a unified framework in which lithium deposition is collectively determined by interfacial Li+ transport flux, transport kinetics, and transport stability. We further emphasize that these transport characteristics are strongly shaped by PVDF-specific features, including semi-crystalline transport heterogeneity, limited lithium salt dissociation, dynamic interface evolution, and discontinuous solid-solid interfacial contact. Representative strategies for regulating these factors are systematically discussed. This review provides mechanistic insight and design guidance for achieving homogeneous lithium deposition and dendrite-free operation in PVDF-based solid polymer lithium metal batteries.