• Summarizes three main modification methods for lithium battery separators: surface coating, in situ modification, and grafting modification.
• Compares adhesion and electrolyte wettability of modified separators prepared by these methods.
• Highlights the role of separators in regulating ion transport and lithium deposition to enhance battery safety and cycle life.
• Proposes future research directions including new materials, manufacturing processes, and quantitative adhesion analysis.