Recent trends in supercapacitor technology; basics, history, fabrications, classifications and their application in energy storage materials

Abstract Supercapacitors (SCs), also known as ultracapacitors or electrochemical capacitors, have attracted significant attention as promising energy storage devices due to their superior power density, rapid charge-discharge capability, and long cycle life. This review comprehensively discusses the recent advancements in supercapacitor technology, focusing on the development of novel electrode materials, electrolytes, device designs, and fabrication methods. Particular emphasis is placed on carbon-based materials, metal oxides, conducting polymers, and their hybrid composites, which have shown remarkable improvements in specific capacitance and stability. Additionally, the role of advanced electrolytes, including ionic liquids and gel polymer electrolytes, in enhancing the energy and power density of SCs is explored. The integration of hybrid supercapacitor systems, combining EDLCs and pseudocapacitors, is also highlighted for their potential to overcome the limitations of conventional capacitors and batteries. This review aims to provide valuable insights into the current progress, emerging trends, and future directions for improving the performance and practical applicability of supercapacitors in real-world energy storage applications.