Study on fabrication of a prototype betavoltaic battery using Ni-63

A betavoltaic battery that converts the decay energy of beta-emitting radioisotopes into electricity is characterized by specialized properties such as a long service lifetime, high energy density, easy small-scale fabrication, and minimum maintenance requirements. It is widely used in low-power applications such as medical devices, micro robots, sensors for monitoring, and power sources for MEMS (microelectromechanical system) because it can operate effectively under extreme environmental conditions. Radioisotope Ni-63, a pure beta emitter, has a low energy spectrum of 17.4 KeV and significantly long half-life of 100.1 years. For this reason, Ni-63 is suitable for the energy source of a betavoltaic battery. In this study, a prototype betavoltaic battery was fabricated using a Ni-63 sealed source and SiC semiconductors. Ni-63 was electroplated onto Ni foil for manufacturing a Ni-63 sealed source using a small-scale electroplating device, and the radioactivity of the fabricated single Ni-63 foil is about 25 mCi/cm². It was bonded to a SiC semiconductor, and a short circuit current (I_sc) and open circuit voltage (V_oc) were then investigated. The unit cells were arrayed 4 × 4 in two PCB. The power output of a betavoltaic battery unit cell was measured at about 6 nW. A whole prototype betavoltaic battery's power output was measured at 145 nW. The prototype betavoltaic battery was fabricated using a Ni-63 sealed source and SiC semiconductors. The radioactivity of the fabricated single Ni-63 foil is about 25 mCi/cm². The unit cells were arrayed 4 × 4 in two PCB. The power output of unit cell was measured at about 6 nW. A whole prototype betavoltaic battery's power output was measured at 145 nW.