Good news! Maybe an intermediate step towards superconductivity?
"discovered that graphene, ... can enhance. an important property of metals called the temperature coefficient of resistance [TCR]. ..
When the research team added 18 parts per million of graphene to electrical-grade copper, the temperature coefficient of resistance decreased by 11 percent ... This is relevant for the manufacturing of electric vehicle motors, where an 11 percent increase in the electrical conductivity of copper wire winding translates into a 1 percent gain in motor efficiency. ...
Previously, the research team performed detailed structural and physics-based computational studies to explain the phenomenon of enhancing the electrical conductivity of metals using graphene. ..."
From the highlights and abstract:
"Highlights
• Copper-graphene feedstock films shear-extruded to bulk copper-graphene wires.
• Adding 18 ppm graphene decreased C11000 TCR by ∼11 % and increased conductivity by ∼1.4 %.
• Microstructure with graphene present as agglomerates and flakes possibly responsible for electrical properties.
Abstract
Copper-graphene composites show remarkable electrical performance surpassing traditional copper conductors albeit at a micron scale; there are several challenges in demonstrating similar performance at the bulk scale. In this study, we used shear assisted processing and extrusion (ShAPE) to synthesize macro-scale copper-graphene composites with a simultaneously lower temperature coefficient of resistance (TCR) and improved electrical conductivity over copper-only samples. We showed that the addition of 18 ppm of graphene decreased the TCR of C11000 alloy by nearly 11 %. A suite of characterization tools involving scanning and transmission electron microscopy along with atom probe tomography were used to characterize the grain size, crystallographic orientation, structure, and composition of copper grains and graphene additives in the feedstock and processed samples. We posit that the shear extrusion process may have transformed some of the feedstock graphene additives into higher defect-density agglomerates while retaining the structure of others as mono-to-tri-layer flakes with lower defect density. The combination of these additives with heterogeneous structures may have been responsible for the simultaneous decrease in TCR and enhanced electrical conductivity of the copper-graphene ShAPE composites."
An Electrifying Improvement in Copper Conductivity Adding a small amount of solid carbon to copper boosts its ability to conduct electricity—industry applications abound
Graphical abstract
Fig. 1. (a). Graphene coated copper (Cu-Gr) foils used to manufacture the feedstock for ShAPE process
Keerti Kappagantula, one of the senior authors of this paper.
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