• Energy Research

MoS2, a typical transition metal dichalcogenide, features a layered structure, multi-phase transition, and tunable band gap, which is a promising candidate for aqueous zinc-ion batteries (AZIBs). Recent studies have focused on the metastable 1T-MoS2 phase, which exhibits superior electrical conductivity and electrochemical activity compared to the more stable 2H phase. Herein, a straightforward one-step hydrothermal method was used to synthesize three-dimensional MoS2/polymer composites (H-MoS2-PEDOT). Under acidic conditions, the polymerization and intercalation of EDOT molecules in the MoS2 layers promote the phase transition from 2H to 1T, thereby enhancing its conductivity and electrochemical performance. Additionally, it was found that the intercalated PEDOT and small amounts of water molecules have contributed to enhancing Zn2+ ion diffusion and cycle stability. As a result, AZIBs based on the H-MoS2-PEDOT composite deliver a high specific capacity of 173.6 mAh g−1 at 1 A g−1, maintaining a specific capacity of 116 mAh g−1 and a capacity retention of 82.8% after 1000 cycles at 5 A g−1.

Radioluminescent isotope cells (RLICs) have the advantages of a long lifetime and high stability due to the use of phosphor material with excellent radiation resistance. Current research efforts mainly focus on the improvement of energy conversion efficiency. This study presents a 63Ni-based RLIC with enhanced photon transport interfaces. The ZnS:Cu phosphor layer is spin-coated directly onto the surface of an AlGaInP-based photovoltaic cell (PC) to achieve efficient coupling of photons by optimizing the transmission interface, and a metal film is sputtered onto the ZnS:Cu layer to reflect radioluminescence towards the PC. Theoretical simulations and experiments are used to compare and validate the integration designs of the ZnS:Cu layer and metal reflective films (Ag, Al, and Ni). It is demonstrated that the RLIC based on the spin-coated ZnS:Cu/PC structure with a 100 nm thick Ag film can increase the output power by 52.6%, compared to conventional RLICs based on adhesive ZnS:Cu/BOPP/PC structure. Maximum efficiency of 0.92% is expected under beta radiation of 63Ni. The enhancement of photon transport is attributed to fluorescence backward reflection and refractive index matching at the interfaces.

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.

Small distributed scientific monitoring equipment is an advanced concept in deep space exploration that requires a special power system. A micro‐radioisotope thermoelectric (TE) generator has the advantages of being of small volume, lightweight, and having a long life, which is regarded as the first choice. An annular radial TE conversion structure integrating 30 TE legs in 8.8 cm3 is designed, and a satisfactory temperature difference of 188.4 K is demonstrated. The p‐type Sb2Te3 and n‐type Bi2Te2.7Se0.3 TE thick films are prepared by screen printing, and Seebeck coefficients are 142.4 and −179.8 μV K−2, respectively. By serial–parallel stacking, modular single‐layer devices are effectively integrated on a large scale. The 900 TE legs are integrated into 15.86 cm3, which can provide a high voltage output of up to 13.2 V. When an electric heating source that simulates 3PuO2 is loaded, an open circuit voltage of 3.84 V and a maximum power of 1.26 mW can be obtained. As a demonstration, a prototype to drive a wireless sensor network is used. In the future, this kind of independent power source is expected to become a help for small autonomous and distributed scientific instruments.

Abstract In view of the current energy demand for miniaturized equipment in extreme environmental fields, such as in deep space exploration. A new fan-shaped radioisotope thermoelectric generator is innovatively presented and designed. Thin-film thermoelectric materials used for miniaturized radioisotope thermoelectric generators are first prepared by electrochemical methods. The prepared fan-shaped radioisotope thermoelectric generator has a volume of 5.75 cm3 and consists of 8 thermoelectric modules and 32 thermoelectric legs. The study finds that when a 1.5 W heat source is loaded, the temperature difference of the device is 54.8 K, the output voltage and the maximum output power is 174.88 mV and 333.20 nW, respectively. On this basis, the number and size of the modules are optimized by the finite element method. When the thermoelectric leg size is optimized to 9 × 2 mm2 and the number of modules is 8, the maximum output power can be up to 369.02 nW. The corresponding experimental verification work is further developed and discussed. This work provides a novel solution for the energy supply problem of small-volume devices in extreme space environments.

Infrared radiation generated by high‐energy‐density radioisotope decay can be converted to electrical energy in radioisotope thermophotovoltaic (RTPV) generators. Thermal emission intensity and spectral properties have substantial implications in this thermal energy conversion process. To improve the performance of the RTPV generator, a silicone coating material is used as a thermal emission enhancer, and SiO2 is used as a filter. The silicone coating has excellent thermal emissivity at high temperatures. The SiO2 filter is used for optical modulation during the thermal energy conversion process. The heat transfer optimization problem caused by the internal temperature distribution of the system is discussed. Compared with the experimental model before optimization, the output power of the RTPV generator increased by 126% obtains an open‐circuit voltage of 2.64 V, an electric power of 89.88 mW, and an energy conversion efficiency of 5.62%. The RTPV generator is expected to be a potential candidate for energy supply in extreme environments.