Synthesis, self-healing mechanisms, and applications of intrinsic and extrinsic self-healing polymer composites in batteries, thermoelectrics, and sensors

The development of self-healing materials, particularly self-healing polymers and polymer composites, has opened new pathways toward materials capable of autonomously repairing damage, thereby extending service life and structural reliability across diverse applications. This review article comprehensively reviews the synthesis strategies, self-healing mechanisms, functional implementations, and related application fields. Self-healing polymers depend on reversible chemical bonds and supramolecular interactions, whereas self-healing polymer composites combine these principles with reinforcement materials to merge self-healing capability with increased mechanical strength. Nevertheless, ensuring long-term durability, addressing the trade-off between self-healing performance and mechanical strength, and the lack of standardized evaluation metrics remain key challenges. Finally, this review introduces representative applications in various electronic-device fields and outlines the remaining hurdles and future outlook for practical implementation.