Recent Advances in Nanocomposite for Lightweight Automotive Materials: A Systematic Review

Vehicle weight reduction is one of the most effective strategies for lowering energy consumption and emissions in both internal combustion and electric vehicles. Nanocomposites have attracted attention because they can significantly improve material properties at very low reinforcement contents. This study maps recent research on nanocomposites for lightweight automotive materials through a systematic review of 88 Scopus-indexed research articles published between 2021 and 2026. The number of articles increased more than sevenfold, from 4 in 2021 to 30 in 2026, and 59.1% of them appeared in the last two years. Polymer matrix nanocomposites dominate the field (45 articles; 51.1%), followed by aluminum matrices (27; 30.7%) and magnesium matrices (11; 12.5%). Graphene and its derivatives, together with carbon nanotubes (CNTs), are the most frequently studied reinforcements, while stir casting and its variants remain the main fabrication route for metal matrices. Nanoscale reinforcement, typically at 0.25–3 wt% in polymers and 1.5–10 wt% in metals, was reported to increase tensile strength by approximately 14–54% and to reduce the coefficient of friction by up to approximately 38%. One life cycle study reported a 28% reduction in component weight compared with a glass fiber composite. Three emerging research directions stand out: hybrid reinforcement, multifunctional materials (flame retardancy, electromagnetic interference shielding, and structural energy storage), and the use of machine learning for property prediction. A critical analysis also found that only 5.7% of the articles reported specific properties, that is, strength or stiffness per unit mass, even though these quantities determine the actual benefit of weight reduction. Most results were obtained on laboratory specimens (indicative technology readiness level 3–4), and the gains are bounded by an optimum filler content above which agglomeration reduces strength. The main open challenges include the dispersion and wettability of nanoparticles, large-scale production, recycling, and the lack of validation on real vehicle components.