Films made from exfoliated graphene flakes have great potential in flexible thermoelectric devices, but are generally limited by the poor quality of flakes and the lack of effective n-doping strategies. The oxidative exfoliation routes typically employed to make reduced graphene oxide (rGO) reduce electrical conductivity because of defects in the basal plane, and typically creates p-type flakes because of the many remaining oxygenous groups. Here, an alternative synthesis strategy using non-oxidative intercalation and molecular adsorption is employed to create high-quality n-type graphene films. A film produced from these non-oxidized graphene flakes (NOGF) showed a Seebeck coefficient of -45.3 mu V K-1 and electrical conductivity of 3280 S cm(-1) at room temperature, both of which are significantly better than previously reported graphene thermoelectric films. This resulted in an extremely high power factor of 673 mu W m(-1) K-2, the highest ever reported from a film made of any 2D material. The films were also shown to be extremely robust under bending conditions, with less than 3% electrical conductivity loss after 1000 bending cycles at a bending radius of 3 mm. Finally, the practicality of the films was demonstrated with a flexible thermoelectric device that generated 2.2 mV using only body heat.