(181g) High Electrical Conductivity Copper Metal-Matrix Composite with Copper Encapsulated Single Walled Carbon Nanotubes

Efficiently transporting electricity is a critical step in the mass adoption of transportation electrification and the ever increasing demand of power transmission. Advanced conductor materials are required to facilitate an electrical future. Mainstream Engineering has developed a carbon nanotube (CNT)-copper metal-matrix composite (MMC) as an advanced conductor material using our non-covalent, wet chemistry based method of decorating CNTs with copper nanoparticles (CuCNT). Individual CNTs have some of the highest electrical conductivities of any known material, making them attractive as an additive in common conductor materials. However, poor CNT-metal interfacial integration has restricted their use to boost the conductivity of common conductors. Functionalizing CNTs can improve the integration with the metal matrix, but can lead to decreased electrical conductivities because of disturbances to the covalent carbon sp² hybridization network present in CNTs. The copper encapsulation method presented functionalizes the CNTs without disrupting the carbon sp² hybridization network, preserving the high electrical conductivity property of the CNTs. The quality of the CNTs undergoing these CuCNTs improve integration into a copper MMC and increase composite conductivity. CuCNT powder was cryogenically ball milled and mixed with pure copper powders, then spark plasma sintered (SPS) into 16 mm x 28 mm cylindrical ingots to create several loadings of CuCNT-MMC. The CuCNT-MMCs ingots were hot extruded to form wires from a diameter of 16 to 2 mm at roughly a meter in length. The wire samples were fabricated at 0.0, 0.1, 0.5, 1.0, 2.0, 5.0, and 10.0 vol% CuCNTs and the conductivity was tested using a four terminal sensing measurement. The maximum conductivity was achieved at 2.0 vol% CuCNT-MMC sample which measured at 59.2 MS/m, representing a 102.2% improvement over the international annealed copper standard (58.0 MS/m). The CuCNT encapsulation process is highly scalable, which could lead to the adoption of the CuCNT-MMC in industrial and commercial settings, paving the way for efficient electrification.