Exploring Efficient Methods for Boosting Capacitance in Graphene and Hybrid Graphene-Based Supercapacitors─A Review

The rapid evolution of energy storage technologies has highlighted supercapacitors as leading candidates due to their high-power density, fast charge–discharge rates, and long cycle life. Graphene, with its excellent conductivity and high surface area, offers strong potential as an electrode material; however, its limited intrinsic capacitance remains a challenge. This review explores recent strategies to enhance the electrochemical performance of graphene-based supercapacitors, focusing on hybridization with pseudocapacitive materials such as metal oxides, carbon nanotubes, MXenes, and conductive polymers. These hybrid systems improve ion transport, mitigate restacking, and contribute additional redox-active sites, collectively boosting energy and power densities. We also examine the role of pore architecture, heteroatom doping, and surface functionalization in optimizing charge storage. Special attention is given to advanced fabrication techniques, including hydrothermal synthesis, electrochemical deposition, and 3D printing, enabling efficient, porous electrode architectures. Finally, we address scalability, stability, and integration challenges for practical applications, and outline future directions for the commercialization of graphene-based supercapacitors in flexible, wearable, and high-energy systems.