The growing concerns over the environmental impact and limited reserves of fossil fuels have accelerated the global shift toward renewable energy sources such as solar and wind. Despite their sustainability, these energy sources are inherently intermittent and unpredictable due to their dependence on time and weather conditions, which pose significant challenges for stable grid integration. To overcome these challenges, large-scale energy storage systems (ESS) have emerged as a critical solution. Among various ESS technologies, redox flow batteries have gained considerable attention owing to their flexible design, independent scaling of power and energy components, and suitability for large-scale applications. In this study, modified electrodes composed of a carbon nanotube (CNT) and graphene hybrid mixture were fabricated on carbon paper (CP) substrates via electrophoretic deposition. The resulting hybrid electrodes were evaluated in both vanadium redox flow battery and quinone-based organic redox flow battery electrolytes. The combination of CNT and graphene significantly enhanced the electrode performance due to their high surface area, excellent electrical conductivity, and electrochemical stability. Electrochemical analyses revealed that the modified electrodes exhibited superior performance compared to bare CP, in terms of both redox kinetics and charge–discharge capacity. This study highlights the potential of hybrid nanocarbons in electrode modification for advanced flow battery systems.