Theoretical investigation of parallel 63NiO/GaP heterojunction nuclear battery with graphene layer and its time-related performance

Betavoltaic (BV) batteries are regarded as appealing power sources due to their high energy densities and long lifetimes. However, the low efficiency and maximum output power density of conventional BV batteries due to the self-absorption effect of radioactive sources, which consist of separate beta-radioactive sources and semiconductor absorbers, limit their applications. In this work, we optimized and compared six ⁶³NiO-related heterojunction nuclear batteries utilizing Monte Carlo software Geant4 and finite element analysis software COMSOL Multiphysics. The ⁶³NiO-related heterojunction nuclear batteries integrate beta-radioactive sources and semiconductor absorbers to overcome the shortcomings of conventional BV batteries. Furthermore, we proposed a parallel connection structure utilizing graphene electrode layer to connect two ⁶³NiO/GaP heterojunctions based on the optimal one from the six heterojunctions in order to maximize the maximum output power density. The total energy conversion efficiency is 2.68% and the maximum output power density is [Formula: see text] of the parallel connection nuclear battery. Finally, we investigated the time-related performance of the parallel connection structure nuclear battery within 200 years. It shows that the maximum output power density decreases from [Formula: see text] in the beginning to [Formula: see text] at 200 years.