Cover Picture: ZnS:Cu Phosphor Layers as Energy Conversion Materials for Nuclear Batteries: A Combined Theoretical and Experimental Study of Their Geometric Structure (Energy Technol. 9/2017). Issue 9 (23rd May 2017) - Xu, Zhiheng
Abstract : Radioluminescent Nuclear Battery : The cover picture illustrates a radioluminescent nuclear battery and the potential applications in future space exploration missions. A conventional beta‐radioluminescent nuclear battery comprises a beta source, phosphor layer, and photovoltaic devices. The radioactive particles decay from two different beta sources to be absorbed in a luminescent compound. This radioluminescence can then be collected and converted to electricity by the photovoltaic devices. In such process with indirect energy conversion, the radioactive particles must transverse through the beta source itself, the phosphors, and the air gap between the source and the phosphor layer. The emitted radioluminescence is a light of specific wavelength range and isotropic angular distribution. As all of the processes influence each other, the structural optimization of the phosphor layers is critical to achieving higher efficiencies, especially for cases in which the battery materials have already been set. In this work, the detailed physical model of a beta radioluminescent nuclear battery is built, the characteristics of utilizing different structures of the phosphor layers as intermediate absorbers are investigated, and the geometrical configuration parameters are shown to have a significant effect on optimizing the energy conversion efficiency. The radioluminescent nuclear battery has high energy density, no moving parts, and a long lifetime, even in the development phase, and appears attractive for defense applications, particularly for long‐term and ultralow power applications. More information can be found in the Full Paper by Xiaobin Tang and colleagues from Nanjing University of Aeronautics and Astronautics onpage 1638 in Issue 9, 2017 (DOI:10.1002/ente.201700036 ).