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1. From thermal conductive to thermal insulating: Effect of carbon vacancy content on lattice thermal conductivity of ZrC

   https://doi.org/10.1016/j.jmst.2020.11.068  

   Zhou, Yue; Fahrenholtz, William G.; Graham, Joseph; Hilmas, Gregory E. (August 2021, Journal of Materials Science & Technology)

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2. Inverse thermal design of nanoporous thin films for thermal cloaking

   https://doi.org/10.1016/j.mtphys.2021.100477  

   Xiao, Yue; Chen, Qiyu; Hao, Qing (November 2021, Materials Today Physics)
3. Thermal analysis of thermoelectric active cooling including external thermal resistances

   https://doi.org/10.1063/5.0176286  

   Marquez_Peraca, Nicolas; Zhu, Qing; Kono, Junichiro; Wehmeyer, Geoff (December 2023, Applied Physics Letters)

   Thermoelectric active cooling uses nontraditional thermoelectric materials with high thermal conductivity, high thermoelectric power factor, and relatively low figure of merit (ZT) to transfer large heat flows from a hot object to a cold heat sink. However, prior studies have not considered the influence of external thermal resistances associated with the heat sinks or contacts, making it difficult to design active cooling thermal systems or compare the use of low-ZT and high-ZT materials. Here, we perform a non-dimensionalized analysis of thermoelectric active cooling under forced heat flow boundary conditions, including arbitrary external thermal resistances. We identify the optimal electrical currents to minimize the heat source temperature and find the crossover heat flows at which low-ZT active cooling leads to lower source temperatures than high-ZT and even ZT→+∞ thermoelectric refrigeration. These optimal parameters are insensitive to the thermal resistance between the heat source and thermoelectric materials, but depend strongly on the heat sink thermal resistance. Finally, we map the boundaries where active cooling yields lower source temperatures than thermoelectric refrigeration. For currently considered active cooling materials, active cooling with ZT < 0.1 is advantageous compared to ZT→+∞ refrigeration for dimensionless heat sink thermal conductances larger than 15 and dimensionless source powers between 1 and 100. Thus, our results motivate further investigation of system-level thermoelectric active cooling for applications in electronics thermal management. 

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4. Flexible percolation fibrous thermal insulating composite membranes for thermal management

   An, Lu; Di_Luigi, Massimigliano; Tan, Jingye; Faghihi, Danial; Ren, Shenqiang (November 2022, Materials advances)

   Flexible thermal insulating membranes are ubiquitous in thermal management. Nevertheless, difficulties arise for composite membranes to combine a resilient, robust structural framework with uniform percolation networks purposefully conceived for thermal insulation. Herein, by controlling the microstructure homogeneity, we report flexible, hydrophobic thermal insulating membranes consisting of ceramic fiber and porous silica materials. The resulting nanofibrous membrane composites exhibit a low thermal insulation of 11.4 mW m−1 K−1, a low density of 0.245 g cm−3, mechanical flexibility with a bending rigidity of 1.25 cN mm−1, and hydrophobicity with a water contact angle of 144°. These nanofibrous-reinforced, silica-aerogel-based nanocomposite membranes are potential candidates for advanced thermal management applications. 

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5. High Thermal Conductivity of Sandwich‐Structured Flexible Thermal Interface Materials

   https://doi.org/10.1002/smll.202207015  

   Jing, Lin; Cheng, Rui; Tasoglu, Muzaffer; Wang, Zexiao; Wang, Qixian; Zhai, Hannah; Shen, Sheng; Cohen‐Karni, Tzahi; Garg, Raghav; Lee, Inkyu (January 2023, Small)

   Abstract Thermal interfaces are vital for effective thermal management in modern electronics, especially in the emerging fields of flexible electronics and soft robotics that impose requirements for interface materials to be soft and flexible in addition to having high thermal performance. Here, a novel sandwich‐structured thermal interface material (TIM) is developed that simultaneously possesses record‐low thermal resistance and high flexibility. Frequency‐domain thermoreflectance (FDTR) is employed to investigate the overall thermal performance of the sandwich structure. As the core of this sandwich, a vertically aligned copper nanowire (CuNW) array preserves its high intrinsic thermal conductivity, which is further enhanced by 60% via a thick 3D graphene (3DG) coating. The thin copper layers on the top and bottom play the critical roles in protecting the nanowires during device assembly. Through the bottom‐up fabrication process, excellent contacts between the graphene‐coated CuNWs and the top/bottom layer are realized, leading to minimal interfacial resistance. In total, the thermal resistance of the sandwich is determined as low as ~0.23 mm² K W⁻¹. This work investigates a new generation of flexible thermal interface materials with an ultralow thermal resistance, which therefore renders the great promise for advanced thermal management in a wide variety of electronics. 

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