A hydrogel nanocomposite composed of reduced graphene oxide (RGO), iron oxide (Fe3O4) nanoparticles, and polyacrylic acid (PM) was prepared using radical polymerization. Different percentages of RGO, Fe3O4, and PAA were used to prepare the nanocomposite. Fourier transform infrared spectroscopy (FTIR) results confirmed the formation of the nanocomposite's chemical structure. X-ray power diffraction (XRD) patterns revealed the principal peak's 2 theta value to be 77.39 degrees with the size of the nanocomposite particles estimated at 96 nm. Results indicated that the electrochemical capacity of the nanocomposites was controlled by the weight percentage of RGO. Increases to the potential scan rate reduced porosity and surface area, thereby decreasing the electrochemical capacity of the nanocomposites. Moreover, increasing the percentage of Fe3O4 nanoparticles in the nanocomposites improved their magnetic characteristics and thermal properties. The latter also improved when the RGO percentage increased. (C) 2017 Elsevier B.V. All rights reserved.