Energy technology最新文献

Supercapacitors are known for their highpower density and excellent cycling stability, but their practicality is often hindered by limited energy density and a narrow potential window. Herein, the energy density can be enhanced by modifying the electrode material and the potential window can be expanded through the use of ionic liquid (IL) electrolytes. In the present study, Co(OH)₂/reduced graphene oxide (rGO) (Co-G) nanocomposite electrodes was synthesized using a simple hydrothermal method while IL-based electrolyte was used as an electrolyte for supercapacitor device fabrication. Morphological analysis reveals a porous honeycomb-like nanostructure with a vertical orientation on the rGO sheet. Electrochemical analysis of the samples is conducted to assess electrode performance, with the Co-G electrode achieving a capacitance of 2156 F g⁻¹ at 1 A g⁻¹. This electrode exhibits lower electrochemical resistance than pure Co(OH)₂. The synthesized material's practicality evaluated in an asymmetric device Co-G/C//AC/C using ionic gel and aqueous gel-based electrolytes. IL-based gel electrolyte device demonstrated superior performance, delivering an energy density of 130 Wh kg⁻¹ and a power density of 3860 W kg⁻¹, maintaining 91% capacitance after 5000 charge–discharge cycles, and outperforming the KOH/PVA gel-based device, highlighting the advantages of ionic gel electrolytes.

Predicting the electrical performance and temperature field of radioisotope thermoelectric generator (RTG) is crucial and essential before they are used in space, a common application scenario. However, building a laboratory to recreate a space environment is expensive and time-consuming. It is also unrealistic to deploy temperature measurement probes in various components of the RTG. This article aims to establish an approach which combines finite element method (FEM) and experimental measurements in the terrestrial laboratory to solve the problem more effectively: first, using FEM to calculate the temperature distribution of RTG operating in the space; second, realizing the similar temperature distribution of self-assembly RTG prototype (electrical thermoelectric generator [ETG]) in the terrestrial laboratory by air cooling. The subsequent measurements of electrical performance indicate that the ETG exhibits a maximum power output of 43.41 W and a maximum thermoelectric conversion efficiency of 5.788% in the simulated space environment, aligning well with the values obtained from FEM. This research has the potential to serve as a method for forecasting the performance of RTG in a terrestrial laboratory.

In this article, we enhance the optical properties of hydrogenated silicon nitride (SiN_x:H) thin film by optimization of deposition conditions using plasma-enhanced chemical vapor deposition (PECVD). Specifically, the impact of varying NH₃:SiH₄ gas ratios (GRs) on the optical and structural properties of the SiNx:H film has been investigated. A ratio of 1.2 results in an optimal refractive index of 2.05, a thickness of 75.60 nm, and a deposition rate of 1.01 nm s⁻¹, achieving the highest optical transmittance of 92.63% at 350 °C. Lower ratios, such as 0.5, produce higher refractive indices up to 2.43 but with reduced transmittance and thinner films (53.67 nm at 84.43% transmittance). The bandgap of GR 1.2 at 350 °C is also calculated as 3.23 eV using Tauc's plot. Fourier transform infrared spectroscopy analysis shows significant variations in SiH hydrogen bonding configurations at different temperatures, affecting SiH and SiNH bond densities. These are crucial for understanding the films’ electronic and optical behaviors, with the highest hydrogen content for SiH noted at 3.30 × 10²² cm⁻³ at 350 °C. This research provides a detailed understanding of how precise control over GRs during PECVD can fine-tune SiN_x film properties, offering guidelines for producing high-quality SiN_x:H layer.