Nuclear batteries provide unique advantages for powering devices in extreme or inaccessible environments such as deep sea, deep space, remote regions, and small-scale sensors. Unlike micro-reactors or “fission batteries,” nuclear batteries harvest the decay energy of radioisotopes, either as heat in radioisotope thermoelectric generators (RTGs/RPS) or directly through radiation energy conversion in betavoltaic or alphavoltaic devices.

Conventional betavoltaic cells employ isotopes such as ⁶³Ni or metal tritides with semiconductor transducers (Si, GaAs, SiC). However, their power conversion efficiency remains low (1–4%), limited by self-shielding, shallow penetration depth, and the technical challenges of handling large amounts of radioisotope. To address these constraints, we have explored alphavoltaic devices with SiC transducers and, more recently, a nuclear photovoltaic (NPV) battery concept. The NPV battery converts high-energy gamma rays into visible scintillation light, which is subsequently harvested by photovoltaic cells. Such systems could be deployed in spent fuel pools or canisters, where high Z scintillators may replace conventional shielding materials and serve the dual function of radiation shielding and power generation.

In our study, a small polycrystalline Schottky CdTe solar cell (1.3 × 1.3 cm², Au contact) was optically coupled to a small GAGG:Ce scintillator (2 × 2 × 1 cm³) and tested under intense Co-60 gamma irradiation. The device achieved a maximum output power of 1.5 μW, demonstrating proof-of-concept for powering low-consumption sensors. In parallel, we also developed an intrinsic betavoltaic battery in which hydrogen atoms in a perovskite lattice were replaced with tritium atoms, enabling the radioisotope to illuminate the device internally. This intrinsic design improved power conversion efficiency by an order of magnitude compared to conventional approaches.