A supercapacitor, also known as an ultracapacitor or electrochemical capacitor, is a high-capacity energy storage device that bridges the gap between conventional capacitors and batteries. It stores and delivers energy using principles of electrostatics and electrochemistry, offering a unique set of capabilities and advantages. With their ability to store and release large amounts of electrical energy quickly, supercapacitors find applications in a wide range of industries. From automotive and transportation, where they provide efficient energy regeneration and power delivery for start-stop systems and hybrid/electric vehicles, to renewable energy storage, where they enhance the stability and reliability of power grids, supercapacitors are revolutionizing energy storage solutions. In addition to their high power density and long cycle life, supercapacitors offer rapid charge and discharge rates, making them ideal for applications that require frequent and fast energy transfer. Their wide operating temperature range, excellent reliability, and compact size further enhance their versatility and feasibility in various demanding environments. Whether used as standalone energy storage devices or in conjunction with other energy sources, supercapacitors are paving the way for a cleaner, more efficient future.