Sulfur particles were coated with conductive polymer layers by dielectric barrier discharge (DBD) plasma technology under atmospheric conditions (ambient pressure and low temperature). The DBD plasma process is a dry and sustainable (solvent-free, limited energy consumption) technique compatible with upscaling. Different conductive coated sulfur materials were produced and labeled as “PEDOT-S” [poly­(3,4-ethylene dioxythiophene-sulfur)], “PANI-S” (polyaniline-sulfur), “PTs-S” (polythiophene-sulfur), and “PPy-S” (polypyrrole-sulfur). The corresponding electrical conductivities were measured at 10–5, 10–6, 10–7, and 10–8 S/cm, respectively. The role of the conductive coating is to enhance the electrochemical performance of Li–S cells by improving the electronic conductivity of the sulfur particles and preventing the well-known polysulfide shuttle phenomenon. A vast range of characterization methods including conductivity analysis, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and carbon-13 NMR (nuclear magnetic resonance spectroscopy) were used to assess the chemical characteristics using the different conductive polymer-coated sulfur materials. In the coated sulfur samples, fragmentation of aromatic rings was observed, 88% for the PTs-S and 42% for the PEDOT-S, while it is very limited for the PANI-S. Such a phenomenon has never been reported in the literature. The uncoated and coated sulfur powders were used (as active material) in positive electrodes of Li–S cells with a relatively high sulfur loading of ∼4.5 mg/cm2 using LiPAA (lithium polyacrylate) as an (aqueous) binder. Long-term galvanostatic cycling at C/10 and multi-C-rate tests showed the capacity fade and rate capability losses to be highly mitigated for cells containing conductive polymer-coated sulfur in comparison to cells using the uncoated sulfur. Kinetic investigations by cyclic voltammetry and electrochemical impedance spectroscopy analyses undoubtedly confirm improved electron and Li-ion transport within the electrodes containing conductive polymer-coated sulfur. The electrochemical performance can be ranked as PEDOT-S > PANI-S > PTs-S > PPy-S > raw sulfur.

As an introduction to this themed issue, a critically selected overview of recent progress on the topic of solution methods for the low‐temperature crystallization of nanoscale oxide materials is presented. It is focused on the low‐temperature solution processing of oxide nanostructures and thin films. Benefits derived from these methods span from minimizing the environmental impact to reducing the fabrication costs. In addition, this topic is regarded as a key objective in the area because it offers a unique opportunity for the use of these materials in areas like flexible electronics, energy conversion and storage, environmental sciences, catalysis, or biomedicine.

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Thermochromic dynamic cool materials present a reversible change of their properties wherein by increasing the temperature, the reflectance, conductivity, and transmittance change due to a reversible crystalline phase transition. In particular, vanadium (IV) dioxide shows a reversible phase transition, accompanied by a change in optical properties, from monoclinic VO2(M1) to tetragonal VO2(R). In this paper, we report on a systematic exploration of the parameters for the synthesis of vanadium dioxide VO2(M1) via an easy, sustainable, reproducible, fast, scalable, and low-cost hydrothermal route without hazardous chemicals, followed by an annealing treatment. The metastable phase VO2(B), obtained via a hydrothermal route, was converted into the stable VO2(M1), which shows a metal–insulator transition (MIT) at 68 °C that is useful for different applications, from energy-efficient smart windows to dynamic concrete. Within this scenario, a further functionalization of the oxide nanostructures with tetraethyl orthosilicate (TEOS), characterized by an extreme alkaline environment, was carried out to ensure compatibility with the concrete matrix. Structural properties of the synthesized vanadium dioxides were investigated using temperature-dependent X-ray Diffraction analysis (XRD), while compositional and morphological properties were assessed using Scanning Electron Microscopy, Energy Dispersive X-ray Analysis (SEM-EDX), and Transmission Electron Microscopy (TEM). Differential Scanning Calorimetry (DSC) analysis was used to investigate the thermal behavior.