World's first metal-free motor could supercharge EVs and spacecraft

Researchers at the Korea Institute of Science and Technology (KIST) have developed the world’s first fully functional electric motor made entirely without metal components, using carbon nanotubes (CNTs) instead of traditional copper coils. This metal-free motor demonstrates a 133% increase in electrical conductivity and is 80% lighter than conventional copper-based motors. The innovation addresses a critical challenge in transportation—lightweighting—which can significantly improve energy efficiency, battery performance, and range in electric vehicles, drones, and spacecraft. The motor was successfully tested by powering a scale model car on asphalt roads, achieving speeds over half a meter per second and continuous operation for 60 minutes under varying loads. A key breakthrough enabling this development was a novel purification technique called the LAST (Lyotropic Liquid Crystal-Assisted Surface Texturing) process. This method removes metal catalyst impurities embedded in CNTs during production, reducing contamination from 12.7% to less than 0.8%, while preserving the nanotubes’ electrical properties. The process involves dissolving CNTs in chlorosulfonic acid to form a liquid crystal state that self-aligns the tubes; exposure to water then generates hydrochloric acid that eliminates iron impurities. The purified CNT cables achieved an electrical conductivity of 7.7 megasiemens per meter, comparable to copper but at a fraction of the weight (1.7 g/cm³ vs. copper’s 8.9 g/cm³). This advancement holds promise for significantly reducing motor weight across various applications without compromising performance.