Subjects: Nuclear Science and Technology >> Radiation Physics and Technology submitted time 2024-06-27
Abstract： Background : Betavoltaic nuclear batteries, leveraging beta-emitting radioisotopes, offer inherent advantages such as long-term reliability, high energy density, compact form factors, and robust resistance to interference, positioning them as promising power sources for self-powered portable or embedded microdevices. Purpose : In order to enhance the conversion efficiency and output power of betavoltaic batteries, we comprehensively considered the effects of backscattering, depletion region width, diffusion length, and electrode structure on charge collection efficiency, conversion efficiency, and output power. Methods : By optimizing the device and electrode structure, we successfully fabricated 63Ni-SiC-based PIN junction betavoltaic batteries with higher overall conversion efficiency and output power, employing Monte Carlo simulations and numerical computations. Results : The fabricated batteries exhibited short-circuit currents, open-circuit voltages, output powers, and total conversion efficiencies ranging from 10.29 to 13.43 nA/cm2, 1.32 to 1.44 V, 11.66 to 14.69 nW/cm2, and 2.24% to 2.82%, respectively. Compared with our team’s previous work, the open-circuit voltage, fill factor, and overall conversion efficiency increased by an average of 127.50%, 114.47%, and 512.10%, respectively. Moreover, the overall conversion efficiency was higher than those reported in the literature (0.5% to 1.99%). Conclusions : These results indicate that by introducing a PIN structure with concentration gradient I- layer, optimizing the depletion region width and doping concentration, and optimizing electrode materials and increasing the spacing between electrode grid lines, the conversion efficiency and output power of betavoltaic batteries can be significantly improved, providing important theoretical guidance and experimental evidence for the design and fabrication of betavoltaic batteries.
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology submitted time 2024-06-27
Abstract： To enhance the performance of betavoltaic batteries, we investigated the effects of depletion region width, diffusion length, and electrode structure on output power. By optimizing the design and improving the fabrication processes of radioisotope source thickness, converter structure, and electrodes, we successfully developed an integrated tritiated titanium-SiC-based betavoltaic battery. Compared to the test results using a discrete tritiated titanium and a converter, the integrated approach of tritiated titanium and the converter significantly improved the output performance of the betavoltaic battery, achieving a maximum output power of 21.4 nW. This performance is among the highest reported for similar betavoltaic batteries. This work provides a valuable reference for developing high-performance betavoltaic batteries.
Subjects: Nuclear Science and Technology >> Engineering of Nuclear Power submitted time 2024-02-01
Abstract： Betavoltaic nuclear batteries offer a promising alternative energy source that harnesses the power of beta particles emitted by radioisotopes. To satisfy the power demands of microelectromechanical systems (MEMS), 3D structures have been proposed as a potential solution. Accordingly, this paper introduces a novel 3D 63Ni-SiC-based P+PNN+ structure with a multi-groove design, avoiding the need for PN junctions on the inner surface, and thus reducing leakage current and power losses. Monte Carlo simulations were performed considering the fully coupled physical model to extend the electron–hole pair generation rate to a 3D structure, enabling the efficient design and development of betavoltaic batteries with complex 3D structures. As a result, the proposed model produces the significantly higher maximum output power density of 19.74 µW/cm2 and corresponding short-circuit current, open-circuit voltage, and conversion efficiency of 8.57 µA/cm2, 2.45 V, and 4.58%, respectively, compared with conventional planar batteries. From analysis of the carrier transport and collection characteristics using the COMSOL Multiphysics code, we provide deep insights regarding power increase, and elucidate the discrepancies between the ideal and simulated performances of betavoltaic batteries. Our work offers a promising approach for the design and optimization of high-output betavoltaic nuclear batteries with a unique 3D design, and serves as a valuable reference for future device fabrication.
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