RESUMEN
Aqueous zinc-ion batteries are considered potential large-scale energy storage systems due to their low cost, environmentally friendly nature, and high safety. However, the development of high energy density cathode materials and uncertain reaction mechanisms remains a major challenge. In this work, the reaction mechanism, discharge voltage and diffusion properties of layered CrO2 as a cathode material for aqueous zinc-ion batteries were studied using first-principles calculations, and the effect of pre-intercalated structural water on the electrochemical performance of CrO2 electrodes is also discussed. The results show that CrO2 exhibits high average discharge voltages (2.65 V for H insertion (pH = 7) and 1.97 V for Zn insertion) and medium theoretical capacities (319 mA h g-1 (H and Zn)). The H intercalation voltage strongly depends on the pH value of the electrolyte. The H/Zn co-insertion mechanism occurs at low hydrogen concentrations (c(H) ≤ 0.125), where the initial insertion of H reduces the total amount of subsequent Zn insertion. For the substrate containing structured water (CrO2·nH2O, n ≥ 0.5), the average voltage of Zn insertion is significantly increased, while the average voltage of H slightly decreases. In addition, the pre-intercalated water strategy significantly improved the diffusion properties of H and Zn. This study shows that layered CrO2·nH2O is a promising cathode material for aqueous zinc-ion batteries, and also provides theoretical guidance for the development of high-performance cathode materials for aqueous zinc-ion batteries.
RESUMEN
This study compares how a modified distributed Bragg reflector (DBR) and yellow color filter (Y-CF) increase the color purity, viewing angle, and brightness of the quantum dot color conversion layer (QDCC) for micro-LED displays. We designed and built a 53-layer high-performance modified DBR with almost total blue leakage filtering (T %: 0.16 %) and very high G/R band transmittance (T %: 96.97 %) for comparison. We also use a Y-CF that filters blue light (T %: 0.84 %) and has good G/R band transmittance (T %: 94.83 %). Due to DBR's angle dependency effect, the modified DBR/QDCC structure offers a remarkable color gamut (117.41 % NTSC) at the forward viewing angle, but this rapidly diminishes beyond 30°. The Y-CF/QDCC structure retains 116 % NTSC color at all viewing angles. Because of its consistent color performance at all viewing angles, sufficient brightness, and outstanding color gamut, the Y-CF/QDCC structure is the best option for contemporary QDCC-based micro-LED displays.
RESUMEN
Superhydrophobic nickel surfaces have significant advantages in the field of corrosion protection compared with traditional nickel corrosion protection methods which need a toxic chemical corrosion inhibitor. Electrochemical etching, an ideal method for fabricating superhydrophobic nickel surfaces, was also limited by low current density, resulting in low processing efficiency. To overcome this limitation, we proposed a new method to fabricate a superhydrophobic nickel surface using a wire electrochemical etching method. The wire electrochemical etching method accomplished the etching process by sweeping a controlled wire cathode across the surface of the anode nickel plate in an environmentally friendly neutral electrolyte, NaCl. The superhydrophobic nickel sample with a contact angle of 153° and a rolling angle of 10° could be fabricated by wire electrochemical etching and modification. Additionally, the optimal parameters of the wire electrochemical etching and the principle of superhydrophobic surface formation had also been systematically investigated, respectively. Moreover, the superhydrophobic nickel surface had self-cleaning performance, antifouling performance, corrosion protection, and abrasion resistance. Wire electrochemical etching improves the current density of processing, which means that this method improves the processing efficiency for fabricating a superhydrophobic nickel surface. This work is expected to enrich the theory and technology for fabricating superhydrophobic nickel surfaces to improve the corrosion protection of nickel.
RESUMEN
Single layered Ti3C2(OH)2 nanosheets have been successfully fabricated by etching its Ti3AlC2 precursor with KOH in the presence of a small amount of water. The OH group replaced the Al layer within the Ti3AlC2 structure during etching, and Ti3C2(OH)2 nanosheets could be easily and efficiently achieved through a simple washing process. The delaminated single-layered nanosheets are clearly revealed by atomic force microscopy to be several micrometers in lateral size. Interestingly, the exfoliated Ti3C2(OH)2 nanosheets could be restacked to form a new layer-structured material after drying. When redispersing this restacked Ti3C2(OH)2 materials in water again, it could be re-delaminated easily only after shaking for several hours. The easy delamination and restacking properties, coupled with intrinsic metallic conductivity and hydrophilicity, make it an ideal two-dimensional building block for fabricating a wide variety of functional materials.
RESUMEN
A facile one-step co-precipitation method has been applied for the synthesis of a Pt decorated octahedral Fe3O4 catalyst. The simple addition of a Pt(4+) and Fe(2+) mixture into a KOH solution leads to the simultaneous formation of an octahedral Fe3O4 and in situ reduction of Pt(4+). HAADF-STEM analysis demonstrates the good dispersion of the Pt species on the Fe3O4 (111) plane, and the resulting material exhibits excellent catalytic activity for CO oxidation under moisture conditions. The inevitably existing moisture contributes to the formation of reaction intermediate [COOH] and hence promotes the catalytic activity, which has been proved through in situ DRIFTS analysis.