Deformable surface design of vertical graphene thermal interface materials for efficient heat dissipation

Vertical graphene, serving as a thermal interface material (TIM), is very promising for efficient thermal dissipating. Yet, the heat-dissipating efficiency is mediocre since satisfactory through-plane thermal conductivity (κ⊥) and contact thermal resistance (Rcontact) cannot be obtained simultaneously. In this work, we achieve TIMs with ultrahigh κ⊥ (738.6 W m−1 K−1) and low Rcontact (29.2 K mm2 W−1) based on volume shrinkage of silver paste within vertical graphene monoliths (VGMs). The outstanding κ⊥ derives from vertically arranged graphene films (GFs) with excellent in-plane thermal conductivity. Besides, the silver pastes between GFs shrink after heating, triggering exposure of soft GF ends and forming a deformable surface to realize a notable decrease in Rcontact. Our VGM TIMs display an enhancement in thermal dissipating efficiency of ∼2.44 times compared to that of the state-of-the-art TIMs. Our findings offer practical design guidelines for advanced TIMs and thermal management applications.