In‐Depth Analysis of the Internal Energy Conversion of Nuclear Batteries and Radiation Degradation of Key Materials

Abstract

Low conversion efficiency and energy output are the main factors hindering the application of the radioluminescent nuclear battery in space. This study analyzes the energy conversion process and proposes a solution of performance promotion. It is found that the energy conversion efficiency of the photovoltaic units is enhanced with increasing incident light intensity. The efficiency of the AlGaInP unit is stable at 22% when the incident energy is at least 3 μW. As for the GaAs unit, the incident threshold value of the photovoltaic response sensitivity is greater than 120 μW. The overall efficiency of the radioluminescent nuclear battery is only 0.37%, consisting of an AlGaInP unit loaded with a low activity 63Ni and the ZnS:Cu phosphor layer. The efficiency increases to 0.87% when an electron radiation source with 270.27 mCi cm−2 is adopted. Moreover, the intense intensity source constitutes an extremely electromagnetic pulse radiation environment, which cause the batteries to fail. The radiation damage is introduced to the phosphor layer by radiation sources, producing agglomerations and cracks on the surface and resulting in the transmittance reduction. This study provides guidance for improving the electrical property and optimization solutions of radioluminescent nuclear battery.

Nuclear batteries: Current context and near‐term expectations

“…Jiang et al investigated the dependence of the overall battery efficiency on the incident energy in a system consisting of a radiant ZnS: (Cu Al) layer coupled with an AlGaInP unit. 104 The 0.37%, efficiency obtained by using a low activity 63 Ni source increased up to 0.87% when the activity density turned up to 270.27 mCi/cm 2 . However, such intense radiations produced structural damages, as agglomerations and cracks on the surface of the phosphor layer, with consequent transmittance decrease and battery failure.…”

“…A further critical point for the betavoltaic‐photovoltaic devices is represented by the intensity of the radioactive source, that needs to take into account the radiation resistance of the used radiant material. Jiang et al investigated the dependence of the overall battery efficiency on the incident energy in a system consisting of a radiant ZnS: (Cu Al) layer coupled with an AlGaInP unit 104 . The 0.37%, efficiency obtained by using a low activity 63 Ni source increased up to 0.87% when the activity density turned up to 270.27 mCi/cm 2 .…”

High Efficiency Formamidinium‐Cesium Perovskite‐Based Radio‐Photovoltaic Cells

“…In an RPV cell, the phosphor converts the decay energy of the radioisotope into optical energy, which is collected by the PV cell to generate electric power output. [2,4,13] Because of the much better radiation resistance of phosphors in comparison to semiconductor materials, RPV cells offer excellent operational stability and long service life.…”

“…[21][22][23][24] Further, they achieved a higher PCE of 0.87% in their latest work by using an electron accelerator to match the high-activity of 147 Pm. [13] Weaver and Schott studied RPV cells with excimer gases (Ar and Xe) and Si PV converters. [25] Radioactive sources such as 210 Po a-radioisotope and 90 Sr b-radioisotope were loaded into the gas aiming to increase the surface interaction between the radioactive source and the phosphor; thus the conversion efficiency of radiation to light could be greatly improved.…”

“…[26][27][28] At present, the performance of RPV cells remains far behind the expectations in terms of power density and PCE, [15,29,30] because it is difficult to improve the photoelectric conversion efficiency of the traditional PV converters at low-intensity illumination from the most commonly used phosphors, ranging from 1 lW cm À2 to 1 mW cm À2 . [13,14] Therefore, overcoming the bottleneck of the low photoelectric conversion efficiency of PV converters in dim light is the key to further improving the performance of RPV cells. Besides, phosphors usually have light emission spectra in the range from 400 to 800 nm with narrow emission peaks.…”