Electrolytic capacitors are a type of capacitor that store electrical energy using an electrolyte, which is a conductive liquid or gel. They are polarized, meaning they have a positive and negative terminal, and are commonly used in electronic circuits for tasks like smoothing out voltage fluctuations and filtering signals. These capacitors are known for their high capacitance values, allowing them to store more energy than other types, such as ceramic or film capacitors. However, they have a limited lifespan and can fail if subjected to excessive voltage or temperature, making proper usage important in electronic design.