A research achievement that breaks the conventional belief that metal is essential for electric motor coils has emerged in the country. This technology, which utilizes carbon nanotubes (CNT) instead of conductive metals, is expected to contribute to both reducing the weight of motors and lowering resource dependence.
Kim Dae-yoon, a principal researcher at the Korea Institute of Science and Technology (KIST) Composite Materials Technology Research Institute, noted that the research team succeeded in constructing electric motor coils solely with carbon nanotubes without metal and implementing them to a level capable of actual operation. This research result was published in the international academic journal "Advanced Composites and Hybrid Materials" in April.
Electric motors are essential components in most electric mobility devices, and the coil represents a significant portion of the overall weight of the motor. So far, metals like copper have been used as the main material for coils due to their high electrical conductivity; however, there have been issues such as difficulties in securing resources, price volatility, and limitations on weight reduction.
The research team focused on CNT to replace the existing coil components. CNTs are nano materials formed in a tube shape with carbon atoms arranged in a hexagonal honeycomb structure, known to be much lighter than regular metals while having high electrical conductivity, mechanical strength, and thermal conductivity.
The research team developed the production process for motor CNTs using the alignment principles of "liquid crystals," which are in an intermediate state between liquid and solid. This method effectively removes impurities remaining on the surface by aligning CNTs like liquid crystals while resolving strong cohesion phenomena. The refined CNT showed significantly improved conductivity.
As a result of conducting experiments by applying coils made of CNT to the motor, it was confirmed that the motor's revolutions per minute (RPM) could be stably controlled according to the input voltage. This case demonstrates that the basic operation of a motor, which converts electrical energy into mechanical rotational force, is possible without metal.
Kim Dae-yoon stated, "We developed a new concept of high-quality CNT technology that did not exist before, maximizing the electrical performance of CNT coils and successfully operating electric motors without metal." He emphasized, "Based on this, we will also take the lead in domestic material development for conductive materials for batteries, pellicles for semiconductors, and cables for robots."
References
Advanced Composites and Hybrid Materials (2025), DOI: https://doi.org/10.1007/s42114-025-01302-4