We report a 'green', simple and efficient approach for the production of graphene oxide (GO) by ultrasonic assisted electrochemical exfoliation of graphite rods, and by using Improved Hummers' graphene oxide (IGO) as an electrolyte. The effects of applied bias, electrolyte concentration and the duration of the electrochemical exfoliation on the quality of the GO nanosheets were investigated. The produced graphene oxide with a high yield (> 48%), and the lowest defect was obtained in the ultrasonic assisted electrochemical exfoliation performed at 0.05% IGO mass percent in DI water and 50 V applied bias for 1 hour at room temperature. The structural, morphological and physical properties of the obtained nanostructures were analyzed by XRD, Raman, FESEM, STEM techniques and thermal conductivity analysis, respectively. The characteristic Raman bands were observed at 1354 cm(-1) and 1590 cm(-1) for the prepared GO nanosheets. The produced graphene oxides exhibited a lateral dimension of 3-7 mu m revealed by field emission scanning electron microscopy (FESEM). It was observed that the thermal conductivity enhancement of 14.95% was obtained for GO, which was higher than the other IGO nanofluid (7.64%) with respect to DI water at 20 degrees C.