High-performance thermal interface materials enabled by vertical alignment of lightweight and soft graphene foams

High-performance thermal interface materials (TIMs) are highly sought after for modern electronics. Two-dimensional (2D) materials as vertical aligned fillers can optimize the out-plane thermal conductivity (k_⊥), but their excessively high content or intrinsic rigidness deteriorate TIMs softness, leading to worsening for thermal contact resistance (R_contact). In this study, 2D graphene materials are fabricated into lightweight and soft graphene foams (GFs) with high-orientation, acting as vertical filler frameworks to optimize the k_⊥ and R_contact for vertical GF (VGF) TIMs. The VGF-TIM has a high k_⊥ of 47.9 W·m⁻¹·K⁻¹ at a low graphene content of 15.5 wt.%. Due to the softness and low filler contents of GFs, the VGF-TIM exhibits a low compressive module (4.2 MPa), demonstrating excellent compressibility. The resulting TIM exhibit a low contact resistance of 24.4 K·mm²·W⁻¹, demonstrating 185.1% higher cooling efficiency in practical heat dissipating scenario compared to commercial advanced TIMs. This work provides guidelines for the design of advanced TIMs and their applications in thermal management.