  With alternate, sustainable, natural sources of energy being sought after,
there is new interest in energy from radioactivity, including natural and waste
radioactive materials. A study of various atomic batteries is presented with
perspectives of development and comparisons of performance parameters and cost.
We discuss radioisotope thermal generators, indirect conversion batteries,
direct conversion batteries, and direct charge batteries. We qualitatively
describe their principles of operation and their applications. We project
possible market trends through our comparative cost analysis. We also explore a
future direction for certain atomic batteries by using nanomaterials to improve
their performance.
