Passive Ultra‐Conductive Thermal Metamaterials

Abstract Ultra‐conductive heat transport showcases significant potentials in popular thermal managements with convection, phase change, and heat source. However, it is captivated impossible for passive thermal manipulation, usually bounded by intrinsic thermal conductivities of natural materials, to outperform these active recipes in need of extra energy payload. Here, a robust recipe to create passive ultra‐conductive thermal metamaterials consisting of nothing but bulk natural materials is reported. Thanks to the local thermal resistance regulation by vertical thermal transport channel, the proof‐of‐concept thermal metamaterials experimentally demonstrate extreme effective conductivity (1915 W m^–1 K^–1) solely with naturally occurring materials. The purely conductive modulation without any external energy is comparable to active counterparts, and further reveals its robustness and unexpected convenience. The findings construct a high‐efficient paradigm of passive thermal management with ultra‐conductive heat transport, and further hint potentials in other Laplace fields, e.g., DC and magnetostatics.