Ultra-high thermal conductivity multifunctional composites with uniaxially oriented boron nitride sheets for future wireless charging technology

The rapid advancement of wireless charging systems (WCSs), fifth-generation (5G) technology, electric vehicles (EVs), and artificial intelligence (AI) systems result in a critical need for more efficient thermal management materials. h-BN, characterized by its ultra-high theoretical thermal conductivity and excellent electrically insulating properties, serves as a promising filler for blending with polymers to develop high-performance thermally conductive composites. However, it is still a challenge to attain a high through-plane thermal conductivity of over 40 Wm⁻¹ K⁻¹ at filler content at 80 vol%. This persistent limitation is mainly attributed to the fact that most current h-BN used in the manufacture of thermal conductive composites has relatively smaller lateral size (below 40 µm). Additionally, the effective orientation strategy (e.g., ice-template strategy) usually results in difficulties in mass production. Here, a two-step process involving blade coating and lamination is used to prepare BN/TPU composites with an through-plane thermal conductivity of 43 Wm⁻¹ K⁻¹ at h-BN content of 67 vol%. With upper-level electric insulating properties and wave-transparent characteristic, the multifunctional BN/TPU composite shows excellent thermal management ability in the high-power wireless charging area and also has the potential to be used in the 5G communication technology field.