Room-temperature ionic liquids (RTILs) are a class of compounds with unique properties, including high charge density, electrochemical stability, low volatility, and tunable polarity. They are widely used as solvents in electrochemical applications due to their ability to mix with each other and various solvents, offering versatile properties. Unlike conventional electrolytes, RTILs lack a solvent and have complex ion structures, leading to different behavior at interfaces. RTILs are important in electrochemistry due to their large electrochemical windows, allowing high electrode charge densities. The article reviews the behavior of RTILs at electrified interfaces (EIs), focusing on their properties, challenges, and applications. RTILs have a complex structure with non-uniform charge distribution, making them liquid at room temperature. Their behavior at interfaces is crucial for understanding their performance as electrolytes. The article discusses the theory of the electrical double layer (EDL) in RTILs, highlighting differences from conventional electrolytes. It also covers experimental studies, electrode reactions, and applications in batteries, fuel cells, solar cells, and flexible energy storage devices. RTILs are important in various fields due to their unique properties and potential applications. The review emphasizes the need for understanding RTIL behavior at interfaces to advance electrochemical applications.Room-temperature ionic liquids (RTILs) are a class of compounds with unique properties, including high charge density, electrochemical stability, low volatility, and tunable polarity. They are widely used as solvents in electrochemical applications due to their ability to mix with each other and various solvents, offering versatile properties. Unlike conventional electrolytes, RTILs lack a solvent and have complex ion structures, leading to different behavior at interfaces. RTILs are important in electrochemistry due to their large electrochemical windows, allowing high electrode charge densities. The article reviews the behavior of RTILs at electrified interfaces (EIs), focusing on their properties, challenges, and applications. RTILs have a complex structure with non-uniform charge distribution, making them liquid at room temperature. Their behavior at interfaces is crucial for understanding their performance as electrolytes. The article discusses the theory of the electrical double layer (EDL) in RTILs, highlighting differences from conventional electrolytes. It also covers experimental studies, electrode reactions, and applications in batteries, fuel cells, solar cells, and flexible energy storage devices. RTILs are important in various fields due to their unique properties and potential applications. The review emphasizes the need for understanding RTIL behavior at interfaces to advance electrochemical applications.