Hot-extruded ultra-conductive carbon aluminum composites for efficient power transmission

The rising demand for efficient energy transmission, driven by the electrification of buildings and transportation, highlights the need for lightweight, cost-effective conductors with improved electrical performance and reduced environmental impact. Aluminum, widely adopted in power transmission applications for its low density, favorable specific conductivity (i.e., conductivity per unit weight), and cost advantages, remains limited by its lower bulk electrical conductivity relative to copper. While prior studies have demonstrated improvements in aluminum conductivity using high-cost carbon nanomaterials such as CVD graphene, their scalability remains a critical barrier to commercial viability. This study explores the potential of coal-derived graphite and graphene as low-cost, scalable additives to enhance the bulk electrical conductivity of aluminum. Carbon-aluminum composite (CAC) 12 AWG wires with varying carbon content and carbon type were fabricated using a commercially mature solid-phase hot extrusion process. The wires were characterized by their microstructure, electrical, and mechanical properties. The best-performing CAC wire, containing 0.05 wt% coal-derived graphene, exhibited an electrical conductivity of 61.8 % IACS, corresponding to a 2.8 % increase over commercial AA1100 wire (60.1 % IACS) and a 2.5 % increase over a control wire (60.3 % IACS). Notably, this enhancement exceeds the highest conductivity improvements previously reported for aluminum composites fabricated with expensive commercial graphene. This work presents the first systematic validation of coal-derived carbons as effective and scalable additives for enhancing electrical conductivity, offering a promising and economically viable route for the development of next-generation conductive materials in energy infrastructure.