Current status and challenges in supercapacitor research

This paper provides a comprehensive review of supercapacitors as an emerging energy storage device, highlighting the various issues and challenges they face. It discusses the progress in energy storage mechanisms, electrode materials, electrolytes, separator materials, and practical applications. The paper summarizes the advantages and disadvantages of electric double-layer capacitance, pseudocapacitance, and hybrid capacitance mechanisms. It evaluates the application prospects of carbon-based materials, metal oxides, and conductive polymers in electrode design; the optimization strategies for aqueous electrolytes, organic electrolytes, and ionic liquids; and the application requirements for biomass-based separators, synthetic polymer-based separators, and inorganic composite separators. In practical applications, supercapacitors demonstrate their function as high-energy storage devices and have shown promising integration in vehicular batteries and lithium-ion battery systems.