A battery that doesn’t need to be recharged for over 30 years: The U.S. wants to achieve this with a material that no one would want near them

27/09/2026 12:30

Updated to

27/09/2026 12:30

Keeping certain devices operational for years without replacing their batteries remains a challenge for the aerospace industry and surveillance systems installed in remote areas. Solar panels are not always feasible, and chemical batteries have limited capacity, especially in devices that need to function continuously. To address this issue, the United States is researching a technology capable of generating electricity for decades using a material that typically requires controlled storage.

The initiative receives $3.37 million in funding from DARPA, the research agency of the U.S. Department of Defense, and is led by Morgan State University. Under the name SYMPHONEE, the project aims to develop a nuclear battery that utilizes strontium-90 radiation to power electronic devices for extended periods. Its main feature is that it does not require recharging to continue generating electricity, although its development still must overcome significant technical and safety challenges.

Strontium-90 enables electricity generation without relying on an external energy source.

The technology being researched by the American consortium is known as betavoltaics and uses semiconductors to convert the energy from certain radioactive emissions into electrical current. When beta particles pass through these materials, they transfer part of their energy and generate electric charges that can be harnessed using a circuit. Its operation is similar to that of a photovoltaic cell, with the difference that it does not require sunlight, as the energy comes from the material’s own radioactive decay.

Strontium-90 is particularly interesting for this application because its half-life is around 29 years, a period during which its radioactive activity is reduced by half. Additionally, its transformation into yttrium-90 produces a second radioactive element that also emits beta particles before turning into stable zirconium. This decay chain allows for a prolonged energy source, although electricity generation gradually decreases over time and does not guarantee constant power throughout the device’s lifespan.

The potential applications of this technology focus on devices that require low levels of electrical power but need it to be sustained for particularly long periods. These include scientific instruments installed in inaccessible locations, surveillance sensors, certain underwater systems, and devices used in space missions. However, increasing the available electricity remains one of the main limitations of betavoltaic batteries, whose power output in commercial applications is usually in the range of nanowatts or microwatts.

The United States aims to increase the power output of these batteries, but significant obstacles still remain.

DARPA’s Rads to Watts program sets as one of its goals achieving a power density of over 10 watts per kilogram, a benchmark that could expand the applications of these devices. Previous research has already shown it is possible to increase electrical output by combining radioactive materials with semiconductors. In fact, a study published in Scientific Reports proposed a 1-watt battery made up of 35 modules, with 45-micrometer layers of strontium-90 interposed between silicon diodes to harness the energy from emitted particles.

The experiments in that research reported conversion efficiencies ranging from 16% to 19%, although the tests used an electron accelerator to simulate radioactive emissions. Therefore, these results do not prove that a strontium-90 battery capable of maintaining such performance for decades already exists.

Safety will also determine any commercial or military application of this technology, as strontium-90 poses health risks if it enters the body and can accumulate in bones due to its chemical behavior similar to that of calcium. Recovering it from nuclear waste requires separation and purification processes, as well as appropriate encapsulation and protection systems to prevent exposure and accidental release of the material.