Controlling anisotropic thermal properties of graphene aerogel by compressive strain.

Materials with adjustable wide-ranging thermal conductivity are desired to tackle the problem of thermal management for electronic devices operating in an extended range of temperature. In this study, graphene aerogels (GAs) are fabricated and transformed from thermal insulators to thermal conductors by high-temperature annealing. The highest through-plane and in-plane thermal conductivity of annealed GA reaches 3.3 and 96 W/m·K, respectively, under 95% compressive strain. Using the annealed GA as thermal interface material leads to superior performance than commercially available products that have higher through-plane thermal conductivity in dissipating heat for high-power electronic devices (e.g., LED lamp). Furthermore, due to excellent elasticity, the thermal resistance of annealed GAs can be reversibly tuned about six-fold by compressive strain. This paves a novel venue in designing thermal management system for devices, which not only need excellent heat dissipation but also good thermal insulation at various operating environments.