High power direct energy conversion by nuclear batteries

The literature on direct conversion of radioisotope energy to electricity is reviewed. Considerations of the choice of radioisotope, converter, and device design are discussed. Recommendations for maximum specific power, energy, and lifetime based on available radioisotopes are made. It is found that nuclear batteries have the potential to achieve specific powers of 1–50 mW/g. Devices that utilize the beta emitter titanium tritide (TiT2) as the isotope are found to have the most potential in the short term to meet the combined performance objectives. TiT2 based devices have a specific power of 0.83 mW/g. Higher specific powers are achievable with the alpha emitter Am241 but with significantly reduced operational lifetime. In order to realize the full operational potential of Am241, radiation resistant converter materials will need to be developed.