The paper reviews the evolution and fundamental aspects of supercapacitors, highlighting their role as a complementary energy storage device to batteries. Supercapacitors offer high power density and fast charge-discharge capabilities, making them suitable for applications requiring short bursts of high power. However, their lower energy storage capacity compared to batteries has driven research efforts to enhance their energy density through novel nanostructured materials, hierarchical pore structures, hybrid devices, and unconventional electrolytes. The paper discusses the main electrochemical measurement methods used to characterize supercapacitor performance, focusing on specific characteristics and limitations. It also delves into the integral components of supercapacitor cells, particularly electrode materials and electrolytes, which determine the device's performance in terms of storage capability, power output, and cycling stability. The paper reviews current advancements in electrode materials, including carbonaceous forms, transition metal-based compounds, conducting polymers, and novel materials, emphasizing the synergy between electrode materials and current collectors. The development of these materials aims to improve the overall performance of supercapacitors, making them more efficient and sustainable.The paper reviews the evolution and fundamental aspects of supercapacitors, highlighting their role as a complementary energy storage device to batteries. Supercapacitors offer high power density and fast charge-discharge capabilities, making them suitable for applications requiring short bursts of high power. However, their lower energy storage capacity compared to batteries has driven research efforts to enhance their energy density through novel nanostructured materials, hierarchical pore structures, hybrid devices, and unconventional electrolytes. The paper discusses the main electrochemical measurement methods used to characterize supercapacitor performance, focusing on specific characteristics and limitations. It also delves into the integral components of supercapacitor cells, particularly electrode materials and electrolytes, which determine the device's performance in terms of storage capability, power output, and cycling stability. The paper reviews current advancements in electrode materials, including carbonaceous forms, transition metal-based compounds, conducting polymers, and novel materials, emphasizing the synergy between electrode materials and current collectors. The development of these materials aims to improve the overall performance of supercapacitors, making them more efficient and sustainable.