Advances in multi-functional composite materials: applications and opportunities in automotive industry

Abstract Multi-functional composite materials are at the forefront of innovation in the automotive sector, offering a fundamental shift from traditional material substitution to integrated system design. These advanced materials combine exceptional structural properties, such as a high strength-to-weight ratio, with one or more engineered functionalities in a single system. This review provides a comprehensive, application-driven overview and comparative evaluation of five key categories of multi-functional composites: sustainable polymer composites, piezoelectric-based composites, nanocomposites, graphene-based composites, and shape memory alloy (SMA) composites. The paper highlights how these materials address critical modern automotive challenges, including the demand for lighter vehicles to improve fuel efficiency and extend electric vehicle range, enhanced crashworthiness for passenger safety, and greater sustainability. Multi-functional composites offer integrated solutions for emerging trends in electrification and autonomous driving; for example, piezoelectric composites can harvest energy from vibrations to power electronics, while SMA composites can dynamically adjust structural stiffness for optimized safety and aerodynamics. This review synthesizes recent advancements, representative applications, industrial challenges, and the commercial readiness of each material class, providing a clear perspective on their role in advancing the performance and sustainability of next-generation vehicles.