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Tin sulphide compounds (SnS x , x = 1, 2) are potential anode materials for potassium-ion batteries (PIBs) due to their characteristic layered structure, high theoretical capacity, non-toxicity and low production cost. However, they suffer from significant volume changes resulting in poor performance of such anodes. In this work incorporation of SnS x into the carbon structure was expected to overcome these disadvantages. Two SnS-based electrode materials encapsulated into chitosan, as a natural carbon source, are fabricated by two different synthesis routes: (a) solvothermal, and (b) solvothermal followed by pyrolysis. The results indicate that the synthesis route is a crucial factor affecting the composition and electrochemical performance of the negative electrode. The electrode material, exhibiting a high reversible capacity (304 mAh/g at 50 mA/g), and good rate capability (128 mAh/g at 1000 mA/g for 500 cycles) is produced by the solvothermal method. The relationship between specific capacity and synthesis procedure is analyzed using the results obtained from XRD, XPS. Additionally, density functional theory is employed to provide deeper insights into the underlying mechanisms governing the electrochemical performance of the SnS x @C electrode materials., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The article delves into the synthesis and characterization of MoS 2 -carbon-based materials, holding promise for applications in supercapacitors and ion batteries. The synthesis process entails the preparation of MoS 2 and its carbon hybrids through exfoliation, hydrothermal treatment, and subsequent pyrolysis. Various analytical techniques were employed to comprehensively examine the structural, compositional, and morphological properties of the resulting materials. The article explores the electrochemical performance of these electrode materials in supercapacitors and ion batteries (LiB, SiB, KiB). Electrochemical measurements were conducted in aqueous electrolyte for supercapacitors and various aprotic electrolytes for ion batteries. Results highlight the impact of the synthesis process on electrochemical performance, emphasizing factors such as capacitance, rate capability, and charge/discharge cycle performance. Hydrothermally treated MoS 2 -carbon exhibited a specific capacitance of approximately 150 F g -1  in supercapacitors, attributed to its high surface area and efficient charge storage mechanisms. Additionally, for Li-ion battery materials without hydrothermal treatment showed impressive capacity retention of around 88% after 500 charge-discharge cycles, starting with an initial specific capacity of about 920 mAh/g. Long-term stability was demonstrated in both supercapacitors and lithium-ion batteries, with minimal capacitance degradation even after extensive charge-discharge cycles. This research underscores the potential of MoS 2 -based materials as effective energy storage solutions., (© 2024. The Author(s).)

This study focuses on the development and optimization of MoO 3 films on commercially available FTO substrates using the pulsed laser deposition (PLD) technique. By carefully selecting deposition conditions and implementing post-treatment procedures, precise control over crystallite orientation relative to the substrate is achieved. Deposition at 450 °C in O 2 atmosphere results in random crystallite arrangement, while introducing argon instead of oxygen to the PLD chamber during the initial stage of sputtering exposes the (102) and (011) facets. On the other hand, room temperature deposition leads to the formation of amorphous film, but after appropriate post-annealing treatment, the (00k) facets were exposed. The deposited films are studied using SEM and XRD techniques. Moreover, electrochemical properties of FTO/MoO 3 electrodes immersed in 1 M AlCl 3 aqueous solution are evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. The results demonstrate that different electrochemical processes are promoted based on the orientation of crystallites. When the (102) and (011) facets are exposed, the Al 3+ ions intercalation induced by polarization is facilitated, while the (00k) planes exposure leads to the diminished hydrogen evolution reaction overpotential., (© 2023. Springer Nature Limited.)

In this work, for the first time, the influence of scaling up the process of titanium dioxide nanotube (TiO 2 NT) synthesis on the photoelectrochemical properties of TiO 2 nanotubes is presented. Titanium dioxide nanotubes were obtained on substrates of various sizes: 2 × 2, 4 × 4, 5 × 5, 6 × 6, and 8 × 8 cm 2 . The electrode material was characterized using scanning electron microscopy as well as Raman and UV-vis spectroscopy in order to investigate their morphology, crystallinity, and absorbance ability, respectively. The obtained electrodes were used as photoanodes for the photoelectrochemical water splitting. The surface analysis was performed, and photocurrent values were determined depending on their place on the sample. Interestingly, the values of the obtained photocurrent densities in the center of each sample were similar and were about 80 µA·cm 2 . The results of our work show evidence of a significant contribution to wider applications of materials based on TiO 2 nanotubes not only in photoelectrochemistry but also in medicine, supercapacitors, and sensors.

In this work, nitrogen-doped porous carbons obtained from chitosan, gelatine, and green algae were investigated in their role as supercapacitor electrodes. The effects of three factors on electrochemical performance have been studied-of the specific surface area, functional groups, and a porous structure. Varying nitrogen contents (from 5.46 to 10.08 wt.%) and specific surface areas (from 532 to 1095 m 2  g -1 ) were obtained by modifying the carbon precursor and the carbonization temperature. Doping nitrogen into carbon at a level of 5.74-7.09 wt.% appears to be the optimum for obtaining high electrochemical capacitance. The obtained carbons exhibited high capacitance (231 F g -1 at 0.1 A g -1 ) and cycle durability in a 0.2 mol L -1  K 2 SO 4 electrolyte. Capacitance retention was equal to 91% at 5 A g -1 after 10,000 chronopotentiometry cycles. An analysis of electrochemical behaviour reveals the influence that nitrogen functional groups have on pseudocapacitance. While quaternary-N and pyrrolic-N nitrogen groups have an enhancing effect, due to the presence of a positive charge and thus improved electron transfer at high current loads, the most important functional group affecting energy storage performance is graphite-N/quaternary-N. The study points out that the search for the most favourable organic precursors is as important as the process of converting precursors to carbon-based electrode materials., (© 2021. The Author(s).)

Tin oxide is one of the most promising electrode materials as a negative electrode for lithium-ion batteries due to its higher theoretical specific capacity than graphite. However, it suffers lack of stability due to volume changes and low electrical conductivity while cycling. To overcome these issues, a new composite consisting of SnO2 and carbonaceous matrix was fabricated. Naturally abundant and renewable chitosan was chosen as a carbon source. The electrode material exhibiting 467 mAh g-1 at the current density of 18 mA g-1 and a capacity fade of only 2% after 70 cycles is a potential candidate for graphite replacement. Such good electrochemical performance is due to strong interaction between amine groups from chitosan and surface hydroxyl groups of SnO2 at the preparation stage. However, the charge storage is mainly contributed by a diffusion-controlled process showing that the best results might be obtained for low current rates.

In this study, we present a novel strategy for enhancing polyaniline stability and thus obtaining an electrode material with practical application in supercapacitors. A promising (graphite foil/polyaniline/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) GF/PANI/PEDOT:PSS) electrode material was characterized and used in the construction of a symmetric supercapacitor that provides an outstanding high power density. For this purpose, the electropolymerization of PANI was carried out on a graphite foil and then a thin protective layer of PEDOT:PSS was deposited. The presence of the nanometer PEDOT:PSS layer made it possible to widen the electroactivity potential range of the electrode material. Moreover, the synergy between materials positively affected the amount of accumulated charge, and thus the thin PEDOT:PSS layer contributed to enhancing the specific capacity of the electrode material. The electrochemical performance of the GF/PANI/PEDOT:PSS electrode, as well as the symmetrical supercapacitor, was investigated by cyclic voltammetry and galvanostatic charge/discharge cycles in 1 M H 2 SO 4 at room temperature. The fabricated electrode material shows a high specific capacitance ( C sp ) of 557.4 Fg -1 and areal capacitance ( C areal ) of 2600 mF·cm -2 in 1 M H 2 SO 4 at a current density of 200 mA·cm -2 (~4 A·g -1 ). The supercapacitor performance was studied and the results show that a thin PEDOT:PSS layer enables cycling stability improvement of the device from 54% to 67% after 10,000 cycles, and provides a high specific capacity (159.8 F·g -1 ) and a maximum specific power (18,043 W·kg -1 ) for practical applications.

In this paper, we demonstrate a novel, electrochemical route of polyaniline/tungsten oxide (PANI)/WO 3 ) film preparation. Polyaniline composite film was electrodeposited on the FTO (fluorine-doped tin oxide) substrate from the aqueous electrolyte that contained aniline (monomer) and exfoliated WO 3 as a source of counter ions. The chemical nature of WO 3 incorporated in the polyaniline matrix was investigated using X-ray photoelectron spectroscopy. SEM (scanning electron microscopy) showed the impact of WO 3 presence on the morphology of polyaniline film. PANI/WO 3 film was tested as an electrode material in an acidic electrolyte. Performed measurements showed the electroactivity of both components and enhanced electrochemical stability of PANI/WO 3 in comparison with PANI/Cl. Thus, PANI/WO 3 electrodes were utilized to construct the symmetric supercapacitors. The impact of capacitive and diffusion-controlled processes on the mechanism of electrical energy storage was quantitatively determined. Devices exhibited high electrochemical capacity of 135 mF cm -2 (180 F g -1 ) and satisfactory retention rate of 70% after 10,000 cycles. The electrochemical energy storage device exhibited 1075.6 W kg -1 of power density and 12.25 Wh kg -1 of energy density. We also investigated the photocatalytic performance of the deposited film. Photodegradation efficiencies of methylene blue and methyl orange using PANI/WO 3 and PANI/Cl were compared. The mechanism of dye degradation using WO 3 -containing films was investigated in the presence of scavengers. Significantly higher efficiency of photodecomposition of dyes was achieved for composite films (84% and 86%) in comparison with PANI/Cl (32% and 39%) for methylene blue and methyl orange, respectively.

In this work, we report the synthesis of hydrated and non-crystalline WO 3 flakes (WO 3-x ) via an environmentally friendly and facile water-based strategy. This method is described, in the literature, as exfoliation, however, based on the results obtained, we cannot say unequivocally that we have obtained an exfoliated material. Nevertheless, the proposed modification procedure clearly affects the morphology of WO 3 and leads to loss of crystallinity of the material. TEM techniques confirmed that the process leads to the formation of WO 3 flakes of a few nanometers in thickness. X-ray diffractograms affirmed the poor crystallinity of the flakes, while spectroscopic methods showed that the materials after exfoliation were abundant with the surface groups. The thin film of hydrated and non-crystalline WO 3 exhibits a seven times higher specific capacitance (C s ) in an aqueous electrolyte than bulk WO 3 and shows an outstanding long-term cycling stability with a capacitance retention of 92% after 1000 chronopotentiometric cycles in the three-electrode system. In the two-electrode system, hydrated WO 3-x shows a C s of 122 F g -1 at a current density of 0.5 A g -1 . The developed supercapacitor shows an energy density of 60 Whkg -1 and power density of 803 Wkg -1 with a decrease of 16% in C sp after 10,000 cycles. On the other hand, WO 3-x is characterized by inferior properties as an anode material in lithium-ion batteries compared to bulk WO 3 . Lithium ions intercalate into a WO 3 crystal framework and occupy trigonal cavity sites during the electrochemical polarization. If there is no regular layer structure, as in the case of the hydrated and non-crystalline WO 3 , the insertion of lithium ions between WO 3 layers is not possible. Thus, in the case of a non-aqueous electrolyte, the specific capacity of the hydrated and non-crystalline WO 3 electrode material is much lower in comparison with the specific capacity of the bulk WO 3 -based anode material.