Beyond graphene basics: A holistic review of electronic structure, synthesis strategies, properties, and graphene-based electrode materials for supercapacitor applications

Abstract

This review presents a comprehensive analysis of graphene-based electrode materials for supercapacitor application, focusing on electronic structure, synthesis strategies, and key attributes. The remarkable 2D-structure of graphene, characterized by sp² hybridized carbon atoms, confers exceptional electronic mobility (100000 cm²V⁻¹s⁻¹), large specific surface area (2600 m²g^-1), and mechanical flexibility (2.4 ± 0.4 TPa), making it an ideal contender for next-generation energy storage devices. We have discussed various synthesis strategies, including CVD, mechanical exfoliation, and chemical reduction, emphasizing their impact on the electrochemical performance of graphene electrodes. The integration of graphene with other nanomaterials, such as metal oxides, TMDs, conducting polymers, and MXenes, is explored to enhance the specific capacitance, cycle stability, and energy density of supercapacitor electrode materials. This review also covers the tunable electronic properties of graphene, addressing charge transport, ion diffusion, and electrochemical performance, which are critical for efficient supercapacitor design. Graphene-based electrodes' flexibility and mechanical stability are examined, highlighting their role in wearable and portable electronic applications. Challenges such as large-scale production, electrode degradation, and cost-effectiveness are also discussed, offering potential solutions through innovative synthesis routes and composite material design. This review provides a holistic perspective on the current advancement of graphene-based electrode materials for supercapacitor applications.