We used wet-spinning method to prepare all-carbon macroscopic hybrid fibers composed of large size graphene oxide (LGO) and carboxylic multiwall carbon nanotubes (MWNT-COOH). The fibers have excellent eletrochemical properties due to the synergistic effect of LGO and MWNT-COOH. The parallelogram shapes of cyclic voltammogram (CV) curves are typical behavior of carbon-based electrochemical double-layer capacitors; Area specific capacity reaches to 32.6mF/cm
2
at 0.1mA/cm
2
in galvanostatic charge and discharge test. Moreover
the hybrid fibers integrate high conductivity and fairly high mechanical properties. The conductivity reaches to 500-800S/m after chemical reduction. The tensile strenghth and Young’s modulus are 377MPa and 4.2GPa
respectively. Hence
graphene-carbon nanotubes hybrid fibers are promising in flexible energy storage devices.