Search Results (13)

Silicon alloy-based materials are widely studied as high-capacity anode materials to replace commercial graphite in lithium-ion batteries (LIBs). Among these, silicon suboxide (SiO_x) offers superior cycling performance compared to pure Si-based materials. However, achieving a high initial Coulombic efficiency (ICE) remains a key challenge. To address this, previous studies have explored Si_xO composites (x ≈ 1, 2), where nano-Si is uniformly dispersed within a Si suboxide matrix to enhance ICE. While this approach improves reversible capacity and ICE compared to conventional SiO, it still falls short of the capacity achieved with pure Si. This study employs a high-energy mechanical milling approach with increased Si content to achieve higher reversible capacity and further enhance the ICE while also examining the effects of trace oxygen uniformly distributed within the Si suboxide matrix. Structural characterization via X-ray diffraction, Raman spectroscopy, and electron microscopy confirm that Si crystallites (<10 nm) are homogeneously embedded within the SiO_x matrix, reducing crystalline Si size and inducing partial amorphization. Electrochemical analysis demonstrates an ICE of 89% and a reversible capacity of 2558 mAh g⁻¹, indicating significant performance improvements. Furthermore, carbon incorporation enhances cycling stability, underscoring the material’s potential for commercial applications. Full article

In this study, we report the synthesis and characterization of hybrid heterostructures composed of red carbon, an organic semiconductor polymer, and the perovskite (NH₄)₃ZnCl₅. Red carbon was synthesized via the polymerization of carbon suboxide (C₃O₂), exhibiting strong light absorption and distinctive optical properties. The hybrid material was obtained by crystallizing (NH₄)₃ZnCl₅ in the presence of red carbon, leading to significant modifications in the optical characteristics of the perovskite. Comprehensive analyses, including X-ray diffraction, FTIR spectroscopy, UV-vis spectroscopy, and cyclic voltammetry, confirmed the formation of a type I heterostructure with enhanced luminescence and potential for advanced optical applications. The energy band alignment suggests that red carbon can function effectively as both a hole and electron transport medium. This work underscores the potential of (NH₄)₃ZnCl₅@red carbon hybrid heterostructures in the development of next-generation optoelectronic devices, including sensors and LEDs. Full article

Although silicon-based anodes have been identified as a potential alternative to conventional graphite anodes, the huge volume change (approximately 300%) that occurs in silicon while cycling still impedes this system from practical applications. In the case of silicon-suboxide (SiO_x)-based anode materials, both Li₂O and LiSiO₄ are formed during the initial lithiation processes and act as a natural volume buffer matrix to accommodate volume changes and the formation of a stable SEI layer, which improves the cyclability and capacity retention. In this study, a series of SiO_x/Si/C-based electrodes composed of different amorphous SiO_x, Si, and graphitic carbon contents were prepared. Among the various investigated compositions, the electrode with a ratio of SiO_x-Si-C equal to 70:12.5:12.5 was found to be optimal in terms of discharge capacity. This promising electrode was pre-lithiated prior to cycling. Finally, 2032-type lithium–sulfur (Li-S) coin cells composed of a S-C/SiO_x-Si-C (pre-lithiated) configuration were assembled and their cycling performances are reported. Full article

The pseudocapacitive effect can improve the electrochemical lithium storage capacity at high-rate current density. However, the cycle stability is still unsatisfactory. To overcome this issue, a multivalent oxide with a carbon coating represents a plausible technique. In this work, a CuO–Cu₂O@C composite has been constructed by a one-step bilayer salt-baking process and utilized as anode material for lithium-ion batteries. At a current density of 2.0 A g⁻¹, the as-prepared composite delivered a stable discharge capacity of 431.8 mA h g⁻¹ even after 600 cycles. The synergistic effects of the multivalence, the pseudocapacitive contribution from copper, and the carbon coating contribute to the enhanced electrochemical lithium storage performance. Specifically, the existence of cuprous suboxide improves the electrochemical conductivity, the pseudocapacitive effect enhances the lithium storage capacity, and the presence of carbon ensures cycle stability. The testing results show that CuO–Cu₂O@C composite has broad application prospects in portable energy storage devices. The present work provides an instructive precedent for the preparation of transition metal oxides with controllable electronic states and excellent electrochemical performance. Full article

Transitioning to more ambitious electrode formulations facilitates developing high-energy density cells, potentially fulfilling the demands of electric car manufacturers. In this context, the partial replacement of the prevailing anode active material in lithium-ion cells, graphite, with silicon-based materials enhances its capacity. Nevertheless, this requires adapting the rest of the components and harmonizing the electrode integration in the cell to enhance the performance of the resulting high-capacity anodes. Herein, starting from a replacement in the standard graphite anode recipe with 22% silicon suboxide at laboratory scale, the weight fraction of the electrochemically inactive materials was optimized to 2% carbon black/1% dispersant/3% binder combination before deriving an advantage from including single-wall carbon nanotubes in the formulation. In the second part, the recipe was upscaled to a semi-industrial electrode coating and cell assembly line. Then, 1 Ah lithium-ion pouch cells were filled and tested with different commercial electrolytes, aiming at studying the dependency of the Si-based electrodes on the additives included in the composition. Among all the electrolytes employed, the EL2 excelled in terms of capacity retention, obtaining a 48% increase in the number of cycles compared to the baseline electrolyte formulation above the threshold capacity retention value (80% state of health). Full article

Magnéli phase titanium oxides, also called titanium sub-oxides (Ti_nO_2n−1, 4 < n < 9), are a series of electrically conducting ceramic materials. The synthesis and applications of these materials have recently attracted tremendous attention because of their applications in a number of existing and emerging areas. Titanium sub-oxides are generally synthesized through the reduction of titanium dioxide using hydrogen, carbon, metals or metal hydrides as reduction agents. More recently, the synthesis of nanostructured titanium sub-oxides has been making progress through optimizing thermal reduction processes or using new titanium-containing precursors. Titanium sub-oxides have attractive properties such as electrical conductivity, corrosion resistance and optical properties. Titanium sub-oxides have played important roles in a number of areas such as conducting materials, fuel cells and organic degradation. Titanium sub-oxides also show promising applications in batteries, solar energy, coatings and electronic and optoelectronic devices. Titanium sub-oxides are expected to become more important materials in the future. In this review, the recent progress in the synthesis methods and applications of titanium sub-oxides in the existing and emerging areas are reviewed. Full article

This study investigated, in detail, the characteristics of the Late Triassic fine-grained sediments in the third member of the Xujiahe Formation (Xu-3 Member), in the Western Sichuan Depression, and the paleoenvironmental evolution during their deposition through petrological interpretation, mineralogical composition characterization, and element geochemical analysis. According to the mineralogical composition, the Xu-3 Member can be divided into two petrological types, namely clayey fine-grained felsic sedimentary rocks and lime fine-grained felsic sedimentary rocks. The main mineral components are siliceous, clay, and carbonate minerals. Through the cluster analysis of major elements, all samples could be divided into two types with different major elemental characteristics. Trace elements exhibited distinct Sr depletion, relative enrichment of large ion lithophile elements, and high field strength elements. Two REE enrichment patterns were observed, which could be attributed to differences in the provenance area and tectonic background. The paleoclimate of the sedimentary area was warm and humid, but it was hotter and drier in the southern and central parts of the depression. The change trend of paleo-productivity was consistent with the paleoclimate. The waters in the sedimentary environment were mainly brackish water to saline water, with fresh water in the southern part of the depression. The paleo-redox conditions of the waters were mainly sub-oxidation to sub-reduction, but the southern part of the depression was more oxidative. The provenance area experienced a moderate degree of chemical weathering under a warm and humid paleoclimate, same as the depositional area. However, the depositional environments differed between the northern and south-central parts of the depression. Full article

To clarify the organic matter (OM) enrichment of the Lishui Sag, the factors influencing the variable abundance of OM in the Lingfeng Formation are studied using organic geochemical data. The source rocks of the Lingfeng Formation have medium–high total organic carbon (TOC) values (0.53–3.56%). The main type of kerogen is II2-III. Compared to the shallow marine subfacies source rocks, the TOC of the delta front subfacies source rocks is higher. The distribution of biomarkers shows that the redox environment of the delta front subfacies source rock is the sub-oxidizing and oxic environment, and the source rock is mainly supplied by terrigenous higher plants; the redox environment of shallow marine subfacies source rocks is a sub-reducing and suboxic environment, and the OM mainly comes from algae. The link between OM input and OM abundance demonstrates that terrigenous OM (TOM) input has a considerable influence on OM abundance. However, there is no obvious relationship between preservation and OM abundance, which suggests that preservation is not the determining element in OM enrichment. The strong sediment flux decreases the amount of time that OM is exposed to oxygen. As a result, delta front subfacies with large TOM input have a huge number of excellent source rocks. This paper proposes a “delta front-OM input model” for excellent source rocks. Full article

We present a detailed study of the structural and electrical changes occurring in two graphene oxide (GO) samples during thermal reduction in the presence of malonic acid (MA) (5 and 10 wt%) and P₂O₅ additives. The morphology and de-oxidation efficiency of reduced GO (rGO) samples are characterized by Fourier transform infrared, X-ray photoelectron, energy-dispersive X-ray, Raman spectroscopies, transmission electron and scanning electron microscopies, X-ray diffraction (XRD), and electrical conductivity measurements. Results show that MA and P₂O₅ additives are responsible for the recovery of π-conjugation in rGO as the XRD pattern presents peaks corresponding to (002) graphitic-lattice planes, suggesting the formation of the sp²-like carbon structure. Raman spectra show disorders in graphene sheets. Elemental analysis shows that the proposed reduction method in the presence of additives also suggests the simultaneous insertion of phosphorus with a relatively high content (0.3–2.3 at%) in rGO. Electrical conductivity measurements show that higher amounts of additives used in the GO reduction more effectively improve electron mobility in rGO samples, as they possess the highest electrical conductivity. Moreover, the relatively high conductivity at low bulk density indicates that prepared rGO samples could be applied as metal-free and non-expensive carbon-based electrodes for supercapacitors and (bio)sensors. Full article

To achieve low-carbon and sustainable development it is imperative to explore water treatment technologies in a carbon-neutral model. Because of its advantages of high efficiency, low consumption, and no secondary pollution, electrocatalytic oxidation technology has attracted increasing attention in tackling the challenges of organic wastewater treatment. The performance of an electrocatalytic oxidation system depends mainly on the properties of electrodes materials. Compared with the instability of graphite electrodes, the high expenditure of noble metal electrodes and boron-doped diamond electrodes, and the hidden dangers of titanium-based metal oxide electrodes, a titanium sub-oxide material has been characterized as an ideal choice of anode material due to its unique crystal and electronic structure, including high conductivity, decent catalytic activity, intense physical and chemical stability, corrosion resistance, low cost, and long service life, etc. This paper systematically reviews the electrode preparation technology of Magnéli phase titanium sub-oxide and its research progress in the electrochemical advanced oxidation treatment of organic wastewater in recent years, with technical difficulties highlighted. Future research directions are further proposed in process optimization, material modification, and application expansion. It is worth noting that Magnéli phase titanium sub-oxides have played very important roles in organic degradation. There is no doubt that titanium sub-oxides will become indispensable materials in the future. Full article

With the increase of zinc resource consumption, the recovery and utilization of zinc resources in zinc suboxide has become one of the current research hotspots. In this study, the electrochemical method was used to remove the impurities in the zinc leaching night and enrich the zinc ferrite in the ammonia leaching residue for the solution and ammonia leaching slag after the ammonia leaching of zinc hypoxide, in order to realize the comprehensive utilization of the essence of zinc immersion night and new resources. The results showed that the reduction potentials of copper, lead, cadmium, and zinc in the ammonia leaching solution were analyzed by electrochemical testing methods to be −0.76 V, −0.82 V, −0.94 V, and −1.3 V, respectively. Through constant potential electrodeposition, the removal rate of copper, lead, cadmium. The removal rate of cadmium is 98.73%, and the removal rate of lead and copper is more than 99%. The purified ammonia leaching solution is evaporated at 90 °C for 25 min to obtain basic zinc carbonate. The purity of ZnO obtained after calcination at 500 °C for 120 min is 96.31%. The ammonia leaching residue was pickled with 3 mol·L⁻¹ acetic acid for 30 min to effectively remove PbCO₃, and then magnetic separation was carried out with a current intensity of 1.4 A. The final zinc ferrite content was 83.83%. Full article

We report a non-hydrolytic sol-gel (NHSG) route to engineer original mesoporous Ti_nO_2n−1@TiO₂/C nanocomposites. The synthetic approach is straightforward, solvent-free, additive-free, and meets the challenge of atom economy, as it merely involves TiCl₄ and THF in stoichiometric amounts. We found that these nanocomposites present enhanced electrocatalytic properties towards the oxygen reduction reaction (ORR) in 0.1 M KOH. We believe that these preliminary results will open a window of opportunity for the design of metal suboxides/carbon nanocomposites through NHSG routes. Full article

Next generation cathode catalysts for direct methanol fuel cells (DMFCs) must have high catalytic activity for the oxygen reduction reaction (ORR), a lower cost than benchmark Pt catalysts, and high stability and high tolerance to permeated methanol. In this study, palladium catalysts supported on titanium suboxides (Pd/Ti_nO_2n–1) were prepared by the sulphite complex route. The aim was to improve methanol tolerance and lower the cost associated with the noble metal while enhancing the stability through the use of titanium-based support; 30% Pd/Ketjenblack (Pd/KB) and 30% Pd/Vulcan (Pd/Vul) were also synthesized for comparison, using the same methodology. The catalysts were ex-situ characterized by physico-chemical analysis and investigated for the ORR to evaluate their activity, stability, and methanol tolerance properties. The Pd/KB catalyst showed the highest activity towards the ORR in perchloric acid solution. All Pd-based catalysts showed suitable tolerance to methanol poisoning, leading to higher ORR activity than a benchmark Pt/C catalyst in the presence of low methanol concentration. Among them, the Pd/Ti_nO_2n–1 catalyst showed a very promising stability compared to carbon-supported Pd samples in an accelerated degradation test of 1000 potential cycles. These results indicate good perspectives for the application of Pd/Ti_nO_2n–1 catalysts in DMFC cathodes. Full article