Reduced graphene oxide (rGO) aqueous dispersions were synthesized from GO suspensions with hydrazine as reducing agent via a microwave-hydrothermal process in ammonia solution. The rGO films were fabricated by vacuum filtration of above dispersions. When the weight ratio of hydrazine to GO (R[Formula: see text]) increases from 0.125 to 9, the dispersion stability of rGO nanosheets in hydrazine/ammonia solution degrades gradually, the surfaces of resultant films become rough from smooth and large interspaces turn up in the transverse section. With the increasing of R[Formula: see text], the C/O atomic ratio and orientation degree of (002) plane of rGO films increase, and the in-plane thermal conductivity also increases, achieving a maximum value of 1056[Formula: see text]W/m K when R[Formula: see text] is 3.375, then decreases because large interspaces in the rGO film with higher reduction degree greatly limit the thermal transport due to the severe phonon scatterings at the sheets boundaries.
