The liquid-like thermoelectric material Cu 2 Se has shown great promise in recent years by virtue of its good electrical properties and inherent low thermal conductivity, which could be optimized by engineering liquid copper ions for further application. Herein, we reported, for the first time, that thermoelectric performance could be remarkably improved via introducing SiC nanoparticles into the Cu 2 Se system. Experimental results proved that additional SiC generated more deformation and stress, which feasibly facilitated more migration of charged copper ions and in turn increased conductivity. A maximum enhancement in electrical conductivity of about 7 times in the composite with 0.05 wt% SiC content was obtained compared with the pure Cu 2 Se, consistent with an increase in phonon scattering by additional interfaces. We obtained a high figure of merit, ZT, of 2.0 at 875 K in the Cu 2 Se/0.05 wt% SiC composite, which was 186% higher than that of the pure Cu 2 Se (∼0.7).