An ultracapacitor is a type of energy storage device that can store and release electrical energy quickly. Unlike traditional batteries, which rely on chemical reactions, ultracapacitors use electrostatic fields to store energy. This allows them to charge and discharge much faster, making them ideal for applications that require quick bursts of power, such as in electric vehicles or renewable energy systems. Ultracapacitors have a longer lifespan compared to batteries, often lasting hundreds of thousands of charge cycles. They are commonly used in conjunction with batteries to enhance performance in systems like hybrid vehicles and solar energy storage, providing a balance between quick energy delivery and long-term energy storage.