  We developed high-performance thermal interface materials (TIMs) based on
few-layer graphene (FLG) composite, where FLG was prepared by the interlayer
catalytic exfoliation (ICE) method. We experimentally demonstrated feasibility
of FLG composites as TIMs by investigating their thermal and mechanical
properties, and reliability. We measured the thermal interface resistance
($R_{int}$) between FLG composite TIMs (FLGTs) and copper and to be 3.2$\pm$1.7
and 4.3$\pm$1.4 $mm^2$K/W for 5 vol.% and 10 vol.% FLGTs at 330 K,
respectively, comparable to or even lower than that of many commercial TIMs. In
addition, the thermal conductivity ($\kappa_{TIM}$) of FLGTs is increased by an
enhancement factor ($\beta$) of ~17 as the FLG concentration increases from 0
to 10 vol.%. We also characterized Vickers hardness and glass transition
temperature ($T_g$) of our FLGTs. We find that our FLGTs are thermally and
mechanically reliable within practical operating temperature and pressure
ranges.
