  We propose a type of thermal interface materials incorporating insulating
nanowires with partially metallic coating in insulating polymer matrix.Large
thermal conductivity can be obtained due to thermal percolation while the
electrical insulation is maintained by controlling $C_{\rm M}\varphi <
\varphi_{\rm c}^{\rm e}$ and $\varphi > \varphi_{\rm c}^{\rm th}$, where
$\varphi$ is the volume fraction of filler, $C_{\rm M}$ is the metallic coating
fraction, $\varphi_{\rm c}^{\rm e}$ and $\varphi_{\rm c}^{\rm th}$ are the
electrical and thermal percolation thresholds, respectively. The electrical
conductivity of such composite materials can further be regulated by coating
configuration. In this regard, we propose the concept of "thermal-percolation
electrical-insulation", providing a guide to design efficient hybrid thermal
interface materials.
