9V rechargeable batteries are a versatile and eco-friendly power solution commonly used in devices that require a higher voltage, such as smoke detectors, remote controls, and portable radios. Unlike traditional disposable 9V batteries, rechargeable versions can be used multiple times, helping to reduce waste and save money over time. These batteries typically use lithium-ion or nickel-metal hydride (NiMH) chemistry, offering a combination of reliable performance and long-lasting power.