An atomic battery, also known as a nuclear battery or radioisotope generator, converts energy released from radioactive isotope decay directly into electricity. Unlike traditional batteries that rely on chemical reactions, atomic batteries harness nuclear decay energy, offering extended longevity and consistent power output. This technology enables long-duration power for specialized applications where conventional power sources are insufficient or impractical. This article explores the historical development and key individuals behind this innovation.
Understanding Atomic Batteries
Atomic batteries capture energy released during radioactive decay and transform it into electrical current. This process differs fundamentally from electrochemical batteries. One method converts heat from radioactive decay into electricity, commonly seen in radioisotope thermoelectric generators (RTGs). These systems use thermoelectric materials, often based on the Seebeck effect, to generate an electric current from a temperature difference.
Another approach involves direct energy conversion, where emitted charged particles (like beta particles) interact with semiconductor materials to create an electrical current without an intermediate heat stage. These are known as betavoltaic cells. RTGs typically produce higher power outputs, while betavoltaic devices can be miniaturized more easily and do not require a thermal gradient. All atomic batteries draw energy from a radioactive source and are characterized by high energy density and ability to operate for many years.
The Genesis of Atomic Batteries
The concept of converting radioactive decay energy into electricity emerged in the early 20th century. British physicist Henry Moseley invented the first atomic battery in 1913. His device used a radioactive radium source to emit charged particles onto a silver-lined glass sphere, building up an electrical charge. While Moseley’s “radium battery” generated high voltages (around 150,000 volts), it produced very low currents and was more a proof of concept for direct charge collection than a practical power source.
A significant breakthrough occurred in the 1950s. In 1953, Paul Rappaport at RCA developed the first betavoltaic cell. This device directly converted energy from beta particles emitted by a radioactive source (strontium-90) into an electrical current using a semiconductor junction. Rappaport’s work marked a pivotal step, yielding a practical, though low-efficiency, atomic battery that demonstrated direct conversion’s feasibility.
Expanding the Technology: Other Key Innovators
Following these initial developments, further innovation led to more robust and versatile atomic battery designs. The 1950s and 1960s saw increased research into long-life power sources, particularly for spacecraft. The Systems for Nuclear Auxiliary Power (SNAP) program, initiated in 1955 by the U.S. Atomic Energy Commission (AEC), played a central role in this expansion. This program focused on developing compact, reliable atomic electric devices for space, sea, and land applications.
A major outcome of the SNAP program was the development of Radioisotope Thermoelectric Generators (RTGs). In 1954, scientists Ken Jordan and John Birden at Monsanto’s Mound Laboratory developed the first RTG, converting heat from radioactive decay directly into electrical energy using thermocouples. These devices became indispensable for deep space missions where solar power was impractical, powering probes like Pioneer, Voyager, and Cassini.
Modern Atomic Battery Applications
Today, atomic batteries serve specialized roles where their unique characteristics are essential. A prominent application is space exploration, where RTGs power spacecraft and rovers, enabling missions far from the sun where solar panels are ineffective. The Voyager spacecraft, launched in 1977, continues to transmit data using its RTGs decades later.
Atomic batteries have also found use in medical implants, such as pacemakers. Some early pacemaker models were powered by nuclear batteries, functioning for over 20 years without replacement. Beyond space and medical devices, these batteries are deployed in remote scientific research stations, underwater sensors, and other critical infrastructure where maintenance is difficult or impossible.