Russian researchers from the Moscow Institute of Physics and Technology (MIPT), the Technological Institute for Superhard and Novel Carbon Materials (TISNCM), and the National University of Science and Technology MISIS have optimized the design of a nuclear battery generating power from the beta decay of nickel-63, a radioactive isotope. Their new battery prototype packs about 3,300 milliwatt-hours of energy per gram, which is more than in any other nuclear battery based on nickel-63, and 10 times more than the specific energy of commercial chemical cells. The paper was published in the journal Diamond and Related Materials.