Niobium‐based oxides including Nb2O5, TiNbxO2+2.5x compounds, M–Nb–O (M = Cr, Ga, Fe, Zr, Mg, etc.) family, etc., as the unique structural merit (e.g., quasi‐2D network for Li‐ion incorporation, open ...and stable Wadsley– Roth shear crystal structure), are of great interest for applications in energy storage systems such as Li/Na‐ion batteries and hybrid supercapacitors. Most of these Nb‐based oxides show high operating voltage (>1.0 V vs Li+/Li) that can suppress the formation of solid electrolyte interface film and lithium dendrites, ensuring the safety of working batteries. Outstanding rate capability is impressive, which can be derived from their fast intercalation pseudocapacitive kinetics. However, the intrinsic poor electrical conductivity hinders their energy storage applications. Various strategies including structure optimization, surface engineering, and carbon modification are effectively used to overcome the issues. This review provides a comprehensive summary on the latest progress of Nb‐based oxides for advanced electrochemical energy storage applications. Major impactful work is outlined, promising research directions, and various performance‐optimizing strategies, as well as the energy storage mechanisms investigated by combining theoretical calculations and various electrochemical characterization techniques. In addition, challenges and perspectives for future research and commercial applications are also presented.
Niobium‐based oxides including Nb2O5, TiNbxO2+2.5x compounds, M–Nb–O family, etc., as the unique structural merit and intercalation pseudocapacitive kinetics, are of great interest for applications in energy storage systems such as Li/Na‐ion batteries and hybrid supercapacitors to gather the scattered energies.
Using synergetic effects of various sodium storage modes and materials to construct high power, high energy, and long cycling flexible sodium anode materials is significant and still challenging. ...Here, by advantageous functional integration of adsorption‐intercalation‐conversion sodium storage mechanisms, a 3D flexible fiber paper anode with the composition of Nb2O5@hard carbon@MoS2@soft carbon is designed and prepared. Based on the synergetic effects, it exhibits higher specific capacity than pure Nb2O5, with more excellent rate performance (245, 201, 155, 133, and 97 mAh g−1 at the current density of 0.2, 1, 5, 10, and 20 A g−1, respectively) than pure MoS2 as well as admirable long‐term cycling characteristics (≈82% capacity retention after 20 000 cycles at 5 A g−1). Relevant kinetics mechanisms are expounded in detail. This work can be helpful for preparing other types of hybrid and flexible electrodes for energy storage systems.
By advantageous functional integration of adsorption‐intercalation‐conversion mechanisms, a 3D flexible Nb2O5@hard carbon@MoS2@soft carbon fiber paper electrode is prepared. This hybrid anode can release the sodium storage advantages of all materials with the aid of synergetic effects. It displays excellent rate performance and long‐term cycling for over 20 000 cycles.
Copper ferrites are emerging transition metal oxides that have potential applications in energy storage devices. However, it still lacks in-depth designing of copper ferrites based anode ...architectures with enhanced electroactivity for lithium-ion batteries. Here, we report a facile synthesis technology of copper ferrites anchored on reduced graphene oxide (CuFeO
@rGO and Cu/CuFe
O
@rGO) as the high-performance electrodes. In the resulting configuration, reduced graphene offers continuous conductive channels for electron/ion transfer and high specific surface area to accommodate the volume expansion of copper ferrites. Consequently, the sheet-on-sheet CuFeO
@rGO electrode exhibits a high reversible capacity (587 mAh g
after 100 cycles at 200 mA g
). In particular, Cu/CuFe
O
@rGO hybrid, which combines the advantages of nano-copper and reduced graphene, manifests a significant enhancement in lithium storage properties. It reveals superior rate capability (723 mAh g
at 800 mA g
; 560 mAh g
at 3200 mA g
) and robust cycling capability (1102 mAh g
after 250 cycles at 800 mA g
). This unique structure design provides a strategy for the development of multivalent metal oxides in lithium storage device applications.
Rapid and accurate assessment of fracture permeability is critical for subsurface resource and energy development as well as rock engineering stability. Fracture permeability deviates from the ...classical cubic law under the effect of roughness, geological stress, as well as mining-induced stress. Conventional laboratory tests and numerical simulations are commonly costly and time-consuming, whereas the use of a connectivity metric based on percolation theory can quickly predict fracture permeability, but with relatively low accuracy. For this reason, we selected two static connectivity metrics with the highest and lowest prediction accuracy in previous studies, respectively, and proposed to revise and use them for fracture permeability estimation, considering the effect of isolated large-aperture regions within the fractures under increasing normal stress. Several hundred fractures with different fractal dimensions and mismatch lengths were numerically generated and deformed, and their permeability was calculated by the local cubic law (LCL). Based on the dataset, the connectivity metrics were counted using the revised approach, and the results show that, regardless of the connectivity metrics, the new model greatly improves the accuracy of permeability prediction compared to the pre-improved model, by at least 8% for different cutoff aperture thresholds.
We investigate the impact of closing a fracture with rough surfaces on the fracture hydraulic diffusivity, which controls the spatiotemporal evolution of pore-pressure perturbations in geological ...formations, particularly those composed of an impermeable matrix and highly permeable natural fractures. We build distributions of synthetic fracture apertures at a reservoir scale (
∼
500 m) from a self-affine model with isotropic Hurst exponents derived from field observations of fault surfaces. To quantify the hydraulic diffusivity of rough fractures, we conduct finite element simulations of transient fluid flow in a single fracture. We use a surface representation of the fracture aperture following the Reynolds lubrication approximation. We verify that our approximation is valid for a steady-state flow and a low Reynolds number (Re
≪
1) from the comparison with a volume-represented fracture aperture model solved by the Navier–Stokes equations for incompressible fluids (INS). Subsequently, the effective hydraulic diffusivity of the rough fracture is estimated by fitting the computed pressure field with the solution of an equivalent parallel plate model. The results show that the long-range correlation aperture field (up to the fault scale) due to self-affinity significantly affects hydraulic pressure diffusion, which is manifested as a strong variability in the pressure distribution with the orientation of the imposed pressure drop. Based on a rigid-plastic rheology, when closing the fracture stepwise from the initial contact to the flow percolation threshold, a decrease in the hydraulic diffusivity over seven orders of magnitude in one direction along the fracture but over four orders of magnitude in the perpendicular direction is obtained. Our results have strong implications for the interpretation of some measured hydraulic diffusivity data as well as for the use of hydraulic diffusivity in interpreting the spatial distribution of fluid-induced seismic events in faulted reservoirs.
Harmful algal blooms (HABs) in natural waters are of escalating global concern due to their detrimental impact on environmental health. Emerging evidence indicates that algae-bacteria symbionts can ...affect HAB features, though much about this interplay remains largely unexplored. The current study isolated a new species of
(type strain JXJ CY 39
) from culture biomass of the bloom-causing
FACHB-905 (Maf) from Lake Dianchi, China. Strain JXJ CY 39
was an aerobic, Gram-stain-negative rod bacterium that grew at 5-38°C, pH 4.0-11.0, and 0-3.0% NaCl. Taxonomic evaluation proposed a new species, with
sp. nov., as the species epithet. Experimental results revealed that strain JXJ CY 39
spurred the growth of Maf by supplying soluble phosphorus and nitrogen during cultivation, despite the unavailability of soluble phosphorus and nitrogen. Additionally, by producing the plant hormone indole-3-acetate, strain JXJ CY 39
possibly impacted Maf's functionality. Results from co-culture experiments with other strains from Maf biomass showed possible effects of strain JXJ CY 39
on the relationship between Maf and other cohabiting bacteria, as well as microcystin toxin production characteristics. Although Maf could foster the growth of strain JXJ CY 39
by supplying organic carbon, the strain's growth could be regulated via specific chemical compounds based on antibiotic assays. Community composition analysis disclosed that this
strain positively affected Maf's growth and modified densities and types of bacteria linked to Maf. Overall, these results suggest that the interactions between important HAB-causing organisms and their attached bacteria are complex, dynamic, and may influence the growth characteristics of algae.
Ameliorating the conductivity and terrible phase aggregation are the primary tasks of tin-based anodes for practical applications in lithium storage. Inspired by this, we have adopted an in-situ gas ...reduction strategy for fine SnS-SnO2 nanoparticles anchoring uniformly on N-doped graphene (C@SnS-SnO2@NGr) to realize superior rate performance in lithium-ion batteries (LIBs) applications. Especially, the better electric contact between SnS and SnO2 can avoid localized reaction of SnMx (M signifies O/S) and retard serious aggregation of Sn/LixSn. As a result, a higher initial Coulombic efficiency (ICE) (78%) was achieved with almost reversible conversion reaction of Sn/Li2M. The capacity retention reaches around 85% at the current density of 0.1 A g−1 for 500 cycles (1120 mA h g−1). Besides, the N-doped graphene as the skeleton benefits the well-distribution of p-n SnS-SnO2 nanoparticles and the conductivity of hybrids. Through high-rate and longest evaluation of 2.0 A g−1, the unique anode still keeps a high capacity of 630 mA h g−1 above 1000 cycles, which accordingly reveals a dominated surface-controlled redox reaction. Correspondingly, the evolution of electrode indicates that the ameliorate conductivity by N-doped graphene and the in-situ gas reduction procedure indeed enhance the charge-transfer kinetics and contribute to a durable high-rate performance.
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•The advanced in-situ gas reduction strategy has been adopted for fine C@SnS-SnO2@NGr.•The C@SnS-SnO2@NGr anode delivers a high initial Coulombic efficiency (ICE) of 78% for lithium ions storage.•It exhibits a boosted rate performance with 630 mA h g−1 reserved at 2.0 A g−1 after 1000 cycles.
Cervical cancer is a significant global health concern, and novel therapeutic strategies are continually being sought to combat this disease. In recent years, selenadiazole found latent therapeutic ...effects on tumors. Herein, investigating the mechanism of selenadiazole in Hela cells holds promise for advancing cervical cancer treatment. Hela cells, a widely utilized model for studying cervical cancer, were treated with selenadiazole, and cell viability was assessed by using the cell counting kit-8 (CCK-8) assay. Changes in mitochondrial membrane potential were evaluated using JC-1 staining, while apoptosis induction was examined using AnnexinV–PI double staining. Intracellular ROS levels were measured by using specific fluorescent probes and the ELIASA system. Additionally, Western blotting was performed to assess the activation of related proteins in response to selenadiazole. Data analysis was performed using GraphPad. Exposure to selenadiazole led to a substantial increase in intracellular redox oxygen species (ROS) levels in Hela cells. Importantly, the induction of ROS by selenadiazole was associated with a marked increase in mitochondrial apoptosis, as evidenced by elevated levels of AnnexinV-positive cells, the JC-1 monomer, caspase-9, and Bcl-2. Furthermore, activation of the JAK2/STAT3 pathway was observed following the selenadiazole treatment. Selenadiazole holds the potential to suppress tumor growth in cervical cancer cells by increasing reactive oxygen species (ROS) levels and inducing mitochondrial apoptosis via the JAK2/STAT3 pathway. This study offers valuable insights into potential cervical cancer therapies and underscores the need for further research into the specific mechanisms of selenadiazole.
Sodium-ion batteries (SIBs) have demonstrated remarkable development potential and commercial prospects. However, in the current state of research, the development of high-energy-density, ...long-cycle-life, high-rate-performance anode materials for SIBs remains a huge challenge. Free-standing flexible electrodes, owing to their ability to achieve higher energy density without the need for current collectors, binders, and conductive additives, have garnered significant attention across various fields. In this work, we designed and fabricated a free-standing three-dimensional flexible Nb2O5@WS2@C carbon nanofiber (CNF) anode based on a hybrid adsorption–intercalation–conversion mechanism of sodium storage, using electrospinning and hydrothermal synthesis processes. The hybrid structure, aided by synergistic effects, releases the advantages of all materials, demonstrating a superior rate performance (288, 248, 211, 158, 90, and 48 mA h g−1 at the current density of 0.2, 0.5, 1, 2, 5, and 10 A g−1, respectively) and good cycling stability (160 mA h g−1 after 200 cycles at 1 A g−1). This work provides certain guiding significance for future research on hybrid and flexible anodes of SIBs.
Developing high-performance anodes is one of the most effective ways to improve the energy storage performances of potassium-ion batteries (PIBs). Among them, Ti-based oxides, including TiO2, ...K2Ti6O13, K2Ti4O9, K2Ti8O17, Li4Ti5O12, etc., as the intrinsic structural advantages, are of great interest for applications in PIBs. Despite numerous merits of Ti-based oxide anodes, such as fantastic chemical and thermal stability, a rich reserve of raw materials, non-toxic and environmentally friendly properties, etc., their poor electrical conductivity limits the energy storage applications in PIBs, which is the key challenge for these anodes. Although various modification projects are effectively used to improve their energy storage performances, there are still some related issues and problems that need to be addressed and solved. This review provides a comprehensive summary on the latest research progress of Ti-based oxide anodes for the application in PIBs. Besides the major impactful work and various performance improvement strategies, such as structural regulation, carbon modification, element doping, etc., some promising research directions, including effects of electrolytes and binders, MXene-derived TiO2-based anodes and application as a modifier, are outlined in this review. In addition, noteworthy research perspectives and future development challenges for Ti-based oxide anodes in PIBs are also proposed.
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