Hierarchically yolk-shell porous carbon sphere as an electrode material for high-performance capacitive deionization

A calculation method for optical properties of yolk shell based on deep learning

The yolk shell is widely used in optoelectronic devices due to its excellent optical properties. Compared to single metal nanostructures, yolk shells have more controllable degrees of freedom, which may make experiments and simulations more complex. Using neural networks can efficiently simplify the computational process of yolk shell. In our work, the relationship between the size and the absorption efficiency of the yolk-shell structure is established using a backpropagation neural network (BPNN), significantly simplifying the calculation process while ensuring accuracy equivalent to discrete dipole scattering (DDSCAT). The absorption efficiency of the yolk shell was comprehensively described through the forward and reverse prediction processes. In forward prediction, the absorption spectrum of yolk shell is obtained through its size parameter. In reverse prediction, the size parameters of yolk shells are predicted through absorption spectra. A comparison with the traditional DDSCAT demonstrated the high precision prediction capability and fast computation of this method, with minimal memory consumption.

Preparation of N-Doped Layered Porous Carbon and Its Capacitive Deionization Performance

In this study, N-doped layered porous carbon prepared by the high-temperature solid-state method is used as electrode material. Nano calcium carbonate (CaCO₃) (40 nm diameter) is used as the hard template, sucrose (C₁₂H₂₂O₁₁) as the carbon source, and melamine (C₃H₆N₆) as the nitrogen source. The materials prepared at 850 °C, 750 °C, and 650 °C are compared with YP-50F commercial super-activated carbon from Japan Kuraray Company. The electrode material at 850 °C pyrolysis temperature has a higher specific surface area and more pores suitable for ion adsorption. Due to these advantages, the salt adsorption capacity (SAC) of the N-doped layered porous carbon at 850 °C reached 12.56 mg/g at 1.2 V applied DC voltage, 500 mg/L initial solution concentration, and 15 mL/min inlet solution flow rate, which is better than the commercial super activated carbon as a comparison. In addition, it will be demonstrated that the N-doped layered porous carbon at 850 °C has a high salt adsorption capacity CDI performance than YP-50F by studying parameters with different applied voltages and flow rates as well as solution concentrations.

Recent progress in materials and architectures for capacitive deionization: A comprehensive review

Capacitive deionization is an emerging and rapidly developing electrochemical technique for water desalination across the globe with exponential growth in publications. There are various architectures and materials being explored to obtain utmost electrosorption performance. The symmetric architectures consist of the same material on both electrodes, while asymmetric architectures have electrodes loaded with different materials. Asymmetric architectures possess higher electrosorption performance as compared with that of symmetric architectures owing to the inclusion of either faradaic materials, redox-active electrolytes, or ion specific pre-intercalation material. With the materials perspective, faradaic materials have higher electrosorption performance than carbon-based materials owing to the occurrence of faradaic reactions for electrosorption. Moreover, the architecture and material may be tailored in order to obtain desired selectivity of the target component and heavy metal present in feed water. In this review, we describe recent developments in architectures and materials for capacitive deionization and summarize the characteristics and salt removal performances. Further, we discuss recently reported architectures and materials for the removal of heavy metals and radioactive materials. The factors that affect the electrosorption performance including the synthesis procedure for electrode materials, incorporation of additives, operational modes, and organic foulants are further illustrated. This review concludes with several perspectives to provide directions for further development in the subject of capacitive deionization. PRACTITIONER POINTS: Capacitive deionization (CDI) is a rapidly developing electrochemical water desalination technique with exponential growth in publications. Faradaic materials have higher salt removal capacity (SAC) because of reversible redox reactions or ion-intercalation processes. Combination of CDI with other techniques exhibits improved selectivity and removal of heavy metals. Operational parameters and materials properties affect SAC. In future, comprehensive experimentation is needed to have better understanding of the performance of CDI architectures and materials.

NiCo alloy/C nanocomposites derived from a Ni-doped ZIF-67 for lightweight microwave absorbers

In this work, we prepared NiCo alloy/C with rhombic dodecahedron structure and superior microwave absorption performance by using ZIF-67 as the raw material. The rhombic dodecahedron NiCo alloy/C was with rough particles on the surface was photographed by field emission scanning electron microscopy. By adjusting the doping amount of Ni and the temperature of pyrolysis, improved the impedance matching of NiCo alloy/C. Specifically, NiCo alloy/C exhibits a minimum reflection loss of -65.48 dB at 13.48 GHz, while the thickness is 1.63 mm. Defects introduced in the Ni doping process and the special rhombic dodecahedral structure can cause multiple loss mechanisms. Therefore, this NiCo alloy/C composite has the potential to be a potential microwave absorber material with lightweight and high microwave absorption properties.

Agricultural waste buckwheat husk derived bifunctional nitrogen, sulfur and oxygen-co-doped porous carbon for symmetric supercapacitors and capacitive deionization

A practical strategy for the value-added utilization of agricultural waste was provide. The buckwheat husk derived N, S, O-co-doped porous carbon was used as bifunctional electrode materials for symmetric supercapacitor and capacitive deionization.