Metallic Thermoelectric Materials for Active Cooling Application

Thermal management is crucial for high-performance integrated circuits (ICs) and Li-ion battery (LIB) powered vehicles. Active thermoelectric (Peltier) cooling and passive (conductive) cooling can be combined to design active heat sinks with high effective thermal conductivity (κeff). To achieve high κeff, both a high power factor (PF) and high passive thermal conductivity are desired. This makes traditional semiconducting thermoelectric (TE) materials, which typically have low thermal conductivity, poor candidates. The proposed work examines the potential of metallic materials for active cooling applications based on their intrinsic high electrical and thermal conductivity. Here, we study selected candidates from two classes of metallic materials: metallic binary alloys and intermetallic f-orbital compounds. Binary alloys with high Seebeck coefficients, such as Cu-Ni, Ni-Fe, and Cr-Mn, are investigated with the goal of achieving high κeff. The potential of low-cost copper-nickel alloys for active cooling applications is explored, in combination with directed energy deposition additive manufacturing, which enables the production of complex geometries and large-scale manufacturing. Nickel-iron alloys with both high power factor and high κeff are also studied, and compositions with peak PF and κeff are examined, accompanied by microstructural analysis. Further trials are conducted on thermoelectrically unexplored binary systems, such as Co-Sn, Co-Al, and Ni-Sn. Additionally, Yb-based intermetallic compounds are screened based on first-principles calculations of the density of states. YbZn₁₁ is investigated for the first time for its thermoelectric properties and doped to improve TE performance. Other Yb-based intermetallic compounds, including Yb-Ag and Yb-Zn, are also explored. We believe our studies will expand current understanding of the thermoelectric performance of metallic materials and their applications in active cooling systems, shedding light on innovative approaches for more efficient cooling solutions and addressing the thermal management challenges in real-world applications.