Ongoing technological advances in d

Ongoing technological advances in diverse fields including portableelectronics, transportation, and green energy are often hindered by the insufficientcapability of energy-storage devices. By taking advantage of two different electrodematerials, asymmetric supercapacitors can extend their operating voltage windowbeyond the thermodynamic decomposition voltage of electrolytes while enabling asolution to the energy storage limitations of symmetric supercapacitors. This reviewprovides comprehensive knowledge to this field. We first look at the essential energy￾storage mechanisms and performance evaluation criteria for asymmetric supercapacitorsto understand the wide-ranging research conducted in this area. Then we move to therecent progress made for the design and fabrication of electrode materials and the overall structure of asymmetricsupercapacitors in different categories. We also highlight several key scientific challenges and present our perspectives onenhancing the electrochemical performance of future asymmetric supercapacitors