Tenfold efficiency improvement of x-ray radioluminescent batteries basing on GAGG:Ce single crystal scintillators

Low energy conversion efficiency and low output power are the major limiting factors of isotope batteries as miniature power supplies for the broad applications, such as micro-electromechanical systems and aerospace electronics. In this work, highly efficient x-ray radioluminescent batteries are demonstrated based on single-crystal scintillators and spectra-matched photovoltaic batteries. X-ray sources are chosen to reduce the backscattering loss, and cerium doped Gd3Al2Ga3O12 (GAGG:Ce) single-crystal scintillators are adopted to improve the radioluminescence efficiency and light coupling efficiency, for their high x-ray absorption ability and high light-yield. The bandgap of photovoltaic battery is also optimized to match the luminescence spectrum of GAGG:Ce to maximize the photovoltaic efficiency. An optimal radioluminescent battery is achieved with an output power of 13.4 μW/cm2 and a conversion efficiency of 1.28%, which is a 10.7-times improvement in the previous best reports (0.12%). This exciting progress indicates the promising potential of radioluminescent batteries in broad applications and will inspire the further exploration for the research community of radioisotope batteries.