<p>Improving the electrochemical performance and durability of supercapacitors remains a critical challenge for high-power energy storage applications. This review evaluates electrode surface coating strategies designed to enhance conductivity, structural stability, and cycling performance. Reported methodologies include in situ polymerization, sol–gel deposition, electrodeposition, and layer-by-layer assembly to apply conductive polymers (e.g., polyaniline and polypyrrole), transition metal oxides (MnO₂, NiO, RuO₂), carbon nanostructures (graphene, carbon nanotubes), and hybrid composite coatings. Comparative analysis shows that optimized coatings can increase specific capacitance by approximately 30–200%, improve capacitance retention to &gt; 90% after 5,000–10,000 cycles, and enhance energy density while maintaining high power delivery. Protective coating layers also suppress electrode corrosion, mitigate mechanical degradation, and improve electrolyte compatibility, leading to longer service life. Emerging bio-derived and environmentally benign coating materials demonstrate promising performance while supporting sustainability goals. Overall, the findings highlight that multifunctional coating architectures combining high conductivity, porosity, and chemical stability are key to achieving durable, high-efficiency supercapacitors suitable for next-generation energy storage systems.</p> Graphical abstract