Graphene-Based Functional Composites: Preparation, Self-Healing Systems and Applications

Graphene is a two-dimensional carbon nanomaterial with atomically thin layered structure. It shows notable mechanical stiffness, charge mobility, thermal conductivity and molecular barrier performance, making it a valuable reinforcing and functionalizing phase for advanced composite systems. Over the past decade, researchers have developed various graphene-incorporated functional composites for applications including self-healing polymers, electrochemical sensors, energy storage electrodes, separation membranes and structural laminates. This review examines mainstream synthesis routes and surface modification approaches for graphene and graphene oxide (GO), focusing on three self-healing composite platforms: polyurethane matrices, hydrogel networks and cementitious materials. For each system, fabrication methods, structure-property relationships and repair mechanisms are discussed. The review also covers applications of graphene-based materials in food safety sensing, lithium-ion battery anodes, water treatment membranes and aerospace structural composites. Despite progress, bottlenecks remain, including poor nanofiller dispersion, weak interfacial adhesion, batch-to-batch variability and high manufacturing cost. These issues limit translation from laboratory demonstrations to industrial use. Optimization strategies are proposed, including hierarchical structural design, precision interface engineering and scalable green manufacturing. This work provides a reference for performance optimization and practical application of graphene-based functional composites.