In this review, a comprehensive overview is given that covers the preparation, characterization, properties, and modification of sol–gel derived SiO2–TiO2 systems toward the generation of advanced ...coatings and powders with desirable properties. First, the fundamentals of the preparation and application of sol–gel derived multicomponent oxide coatings and powders are reviewed. Then, the basic physical and chemical properties of sol–gel derived SiO2–TiO2 coatings and powders are described. After that, the morphological and structural modification of sol–gel derived SiO2–TiO2 systems using organic polymers and surfactants, via their reaction in water vapor and hot water under external fields, are discussed. Finally, the advanced functionalities, such as superhydrophilicity, photocatalytic activity, micropatterning, and holographic recording, of the sol–gel derived SiO2–TiO2 coatings are demonstrated. In this context, the contributions of the author in this research field are also presented.
Transforming solar energy into chemicals through the photoelectrochemical or photocatalytic water-splitting process is considered a powerful technique for implementing an effective, clean, and ...affordable energy source. The main issues are charge carriers recombination, the large bandgap of the photocatalysts, and the occurrence of the back (water-forming) reaction. The decoration of plasmonic metal nanoparticles onto semiconductors has recently been reported as an auspicious technique to overcome these limitations and promote photocatalytic activity through the transfer of plasmonic energy from the plasmonic metal nanoparticles to the semiconductor. This review focuses on three main objectives: surveying the main features of the plasmonic metal nanostructure that influence its photocatalytic activity; providing a brief explanation of the four main mechanisms of the plasmonic energy transfer, and summarizing some noteworthy recent plasmonic photocatalysts which widely investigated for photocatalytic or photoelectrochemical water splitting with emphasis on their influence on the behavior of charge carriers.
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•The semiconductor/PNPs composites can promote the PC activity of water-splitting.•Photocatalysts with high crystallinity exhibit high activity for water splitting.•Plasmonic energy transfer to the semiconductor via light trapping, HEI, and PIRET.•Water-splitting systems should be designed to work across the whole solar spectrum.
The significance of graphene and its two-dimensional (2D) analogous inorganic layered materials especially as hexagonal boron nitride (h-BN) and molybdenum disulphide (MoS
2
) for “clean energy” ...applications became apparent over the last few years due to their extraordinary properties. In this review article we study the current progress and selected challenges in the syntheses of graphene, h-BN and MoS
2
including energy storage applications as supercapacitors and batteries. Various substrates/catalysts (metals/insulator/semiconducting) have been used to obtain graphene, h-BN and MoS
2
using different kinds of precursors. The most widespread methods for synthesis of graphene, h-BN and MoS
2
layers are chemical vapor deposition (CVD), plasma-enhanced CVD, hydro/solvothermal methods, liquid phase exfoliation, physical methods etc. Current research has shown that graphene, h-BN and MoS
2
layered materials modified with metal oxide can have an insightful influence on the performance of energy storage devices as supercapacitors and batteries. This review article also contains the discussion on the opportunities and perspectives of these materials (graphene, h-BN and MoS
2
) in the energy storage fields. We expect that this written review article including recent research on energy storage will help in generating new insights for further development and practical applications of graphene, h-BN and MoS
2
layers based materials.
The demand for electromagnetic interference (EMI) shielding has increased strongly in the last few years, owing to the fast technological developments in the electronics industry. In order to meet ...these markedly increased demands, many new layer-structured materials (as well as other structures with various morphologies) are being investigated to replace conventionally used metal sheets for the purpose of EMI shielding. Carbon-based nanostructures and their composites are used for EMI protection due to their low weight, cost-effectiveness, and good thermal/electrical properties. Polymers are also low density materials, with the added benefits of low cost and easy processing. Composites combining various polymers with different types of conducting carbon fillers have been proposed as EM wave absorbers. MXene-based 2D layered materials have also received tremendous attention for application in EMI shielding. In this review article, we have systematically summarized the recent research on materials designed for microwave/radio wave absorption and EMI shielding. The text covers carbon-based nanostructured materials, various kinds of polymers, layered inorganic materials and their composite hybrids. The review is concluded with a brief discussion of the perspectives and outstanding challenges for future EMI shielding applications of carbon, polymers and MXene-based materials.
The main classes of materials used for EMI shielding and possible attenuation mechanisms for EM waves incident on a slab of EMI shielding material. Display omitted
The importance of graphene and its derivatives for “clean energy” applications became apparent over the last few years due to their exceptional characteristics, especially regarding electrical, ...thermal and chemical properties. In this review article we examine the recent progress and some of the challenges in the syntheses and modification of graphene-based materials, including energy storage applications as electrodes in Li-ion batteries (LIBs). Various synthesis routes have been used for obtaining graphene using different kinds of carbon sources (graphite, non-graphitic carbon and carbon-containing materials). The most popular processing methods include epitaxial growth, liquid phase chemical/electrochemical exfoliation, mechanical exfoliation, chemical vapor deposition and laser-assisted synthesis. Taking the reduction approach, chemical, thermal, microwave and laser reduction methods have been applied to prepare graphene from graphene oxide/graphite oxide. Recent research has shown that graphene derivatives and hybrids/ nanocomposites using metal oxides/mixed metal oxides and metal sulfides/mixed metal sulphides can have a profound impact on the performance of energy storage devices. Closing the text, we speculate on the future prospects for the application of graphene and its derivatives in energy storage devices. We expect that this review article will help in generating new insights for further development and practical applications of graphene-based materials.
Abstract
Synthesis technology for sulfide-based solid electrolytes based on liquid-phase processing has attracted significant interest in relation to achieving the optimal design for all-solid-state ...batteries. Herein, guidelines to solvent selection for the liquid-phase synthesis of superionic conductor Li
7
P
3
S
11
are described through systematic examination. 70Li
2
S–30P
2
S
5
system, a source of Li
7
P
3
S
11
, is treated via a wet chemical reaction using eight organic solvents with different physical and chemical properties (i.e., dielectric constant, molecule structure, and boiling point). We reveal that the solvent’s polarity, characterized by the dielectric constant, plays an important role in the formation of crystalline Li
7
P
3
S
11
via wet chemical reaction. In addition, acetonitrile (ACN) solvent with a high dielectric constant was found to lead to high-purity crystalline Li
7
P
3
S
11
and intrinsically high ionic conductivity. Further, solvents with a high boiling point and ring structures that cause steric hindrance were found to be unfavorable for the wet chemical synthesis of Li
7
P
3
S
11
solid electrolyte. Overall, we demonstrate that ACN solvent is the most suitable for the liquid-phase synthesis of a crystalline Li
7
P
3
S
11
solid electrolyte with high purity based on its dielectric constant, molecular structure, and boiling point.
In this article, we have demonstrated single-step as well as scalable synthesis of zinc oxide nanoparticles (ZnO NPs) supported on highly thin/transparent reduced graphene oxide (rGO) nanocomposite ...(ZnO@rGO) via direct microwave irradiation using decomposition of zinc acetate dihydrate (Zn(CH
3
CO
2
)
2
·2H
2
O) along with reduction of graphite oxide. The surface microstructure of prepared ZnO@rGO nanocomposite was analyzed by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, and X-ray photo electron spectroscopy. Different characterization analysis indicates that the ZnO NPs in the nanocomposite were dispersed on the surfaces of rGO nanosheets (NSs). Raman spectra reveal the structural defects level of rGO NSs was 0.78, while it was increased to 1.66 for ZnO@rGO nanocomposites. The synthesized ZnO@rGO nanocomposite exhibits specific capacitance of 102.4 F/g at the scan rate of 30 mV/s and shows good cyclic stability of 82.5% for 3000 cycles at high scan rate 100 mV/s.
The decomposition behavior of electrolytes affects the cycle stability and electrochemical redox activity in all-solid-state lithium–sulfur batteries (ASSLSBs). However, there is a sparse ...understanding of the electrochemistry of ASSLSBs involving the oxidative decomposition of sulfide solid electrolytes (SEs) due to the lack of fundamental studies. Herein, we unveil the redox chemistry related to Li2S/S conversion reaction, electrolyte decomposition, and redox reaction of the decomposition product, based on differential capacity curves. The oxidation reaction of Li2S proceeds simultaneously with a continuous oxidative decomposition of sulfide SEs. Raman spectroscopy of the cell after cycling shows that SEs in the cathode convert the thiophosphates with a S–S thiol bond via the decomposition behavior of the electrolytes. The implication of this reaction chemistry is expanded toward understanding the Li2S activation process in ASSLSBs. Additionally, we demonstrate that Li2S/SE interface modification by different rotation speeds of ball milling in SE mixing allows us to control the decomposition kinetics of electrolytes. The severe decomposition of electrolytes causes cycle fading instead of increasing the electrochemical redox activity in the early period. The findings of this work highlight the need for interface engineering to avoid severe degradation of electrolytes in the cathode and enhance the ability of SEs as a redox mediator.
The stability of sulfide-based solid electrolytes (SEs) in ambient air is a critical criterion for the application of all-solid-state lithium-ion batteries. Air-stable Li3SbS4–LiI SEs were ...synthesized using a unique process in an aqueous solution under ambient air, i.e., an ion-exchange (IE) process. The crystalline structure of Li3SbS4 obtained by this process was confirmed by X-ray diffraction (XRD) patterns. The ionic conductivity of the obtained SE was 8.5 × 10–8 S cm–1 at 50 °C. The SEs of Li3SbS4–LiI were also synthesized via the IE process. The temperature dependence of the Li3SbS4–LiI SEs’ ionic conductivities showed a unique behavior; for example, the conductivities of 60Li3SbS4·40LiI (LSbSI) rapidly increased upon heating from 1.8 × 10–7 S cm–1 at 26.5 °C to 8.4 × 10–3 S cm–1 at 65 °C. The LiI layers on LSbSI are responsible for the unique temperature dependence of conductivity determined by differential scanning calorimetry–XRD measurement. Further, the dehydrated LSbSI obtained by milling and annealing showed a high conductivity of 1.3 × 10–4 S cm–1 at a low temperature of 25 °C. A cathode composite containing the active material of Ti2S and the LSbSI SE obtained via the IE process was prepared by freeze-drying. The all-solid-state cell using the cathode composite, which consists of Li–In/SE/TiS2–LSbSI, showed good performance at 60 °C as a lithium-ion secondary battery.
All-solid-state lithium-ion batteries (ASSLBs) have the potential to be the next-generation energy storage systems because of their high safety features. However, one of the major challenges to the ...commercialization of ASSLBs is the development of well-established large-scale manufacturing techniques for solid electrolytes (SEs). Herein, we synthesize Li6PS5X (X = Cl, Br, and I) SEs in a total of 4 h by a rapid solution synthesis method using excess elemental sulfur as a solubilizer and reasonable organic solvents. In the system, trisulfur radical anions stabilized by a highly polar solvent increase the solubility and reactivity of the precursor. Raman and UV–vis spectroscopies reveal the solvation behavior of halide ions in the precursor. This result demonstrates that the solvation structure modified by the halide ions determines the chemical stability, solubility, and reactivity of chemical species in the precursor. The prepared Li6PS5X (X = Cl, Br, and I) SEs show ionic conductivities of 2.1 × 10–3, 1.0 × 10–3, and 3.8 × 10–6 S cm–1 at 30 °C, respectively. Our study provides a rapid synthesis of argyrodite-type SEs with high ionic conductivity.
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