Nuclear batteries, also known as radioisotope thermoelectric generators (RTGs), are devices that convert the heat released from radioactive decay into electrical energy. They use isotopes like plutonium-238 to generate power, making them suitable for long-term energy needs in remote locations, such as space missions. These batteries have a long lifespan, often lasting several decades without needing replacement. Their reliability and ability to function in extreme conditions make them ideal for applications in satellites, space probes, and even some medical devices. However, safety concerns regarding radioactive materials are important considerations in their use.