Path Of Electrons Research Articles

Nonclassical Optical Response of Particle Plasmons With Quantum‐Informed Local Optics

AbstractAs the dimensions of plasmonic structures or the field confinement length approach the mean free path of electrons, mesoscopic optical response effects, including nonlocality, electron spill‐in or spill‐out, and Landau damping, are expected to become observable. In this work, a quantum‐informed local analogue model (QILAM) that maps these nonclassical optical responses onto a local dielectric film is presented. The primary advantage of this model lies in its compatibility with the highly efficient boundary element method (BEM), which includes retardation effects with relatively large particle sizes. Furthermore, the approach offers a unified framework that connects two important semiclassical theories: the generalized nonlocal optical response (GNOR) theory and the Feibelman d‐parameters formalism. It is envisioned that QILAM can evolve into a multiscale electrodynamic tool for exploring nonclassical optical responses in diverse plasmonic structures in the future. This can be achieved by directly translating mesoscopic effects into observable phenomena, such as plasmon resonance energy shifts and linewidth broadening in the scattering spectrum.

Coating MOF Layer on Fe3O4 Nanoparticles Towards Enhancing Photocatalysis Activation of Peroxydisulfate via Layer Thickness Control

ABSTRACTAs the photocatalytic layer, metal organic frameworks (MOFs) with thickness control were coated on the surface of Fe3O4 nanoparticles to investigate the influence of photocatalysis on the activation of peroxydisulfate to degrade antibiotic pollutants. A suitable thickness of MOF layer can not only enhance the adsorption of the substrate molecules on the composite catalyst but also provide optimized electron transfer distance and path, which is conducive to improving the efficiency of electron–hole separation, thereby enhancing the activation of peroxydisulfate and the degradation efficiency of pollutants.

Multidimensional core-shell nanocomposite of iron oxide-carbon tube and graphene nanosheet: A lithium-ion battery anode with enhanced performance through structural optimization

A novel multidimensional composite of 1D iron oxide (Fe3O4)-carbon tube and 2D graphene nanosheet (GNS) was demonstrated to be used as the anode material for lithium-ion batteries (LIBs). Fe3O4-carbon tube-GNS manifested a unique core–shell composite structure, where the Fe3O4 nanoparticles were embedded in the carbon tube with the GNS. The material characterization confirmed that the Fe3O4 nanoparticles were embedded in the highly graphitized carbon tube with the dispersed GNS. Fe3O4-carbon tube-GNS exhibited a high porosity (surface area: 62.3 m2/g, pore volume: 0.112 m3/g). It also exhibited an excellent electrochemical performance with a high reversible capacity (900 mAh/g at 1 A/g), a high coulombic efficiency (∼100 % for 100 cycles), and good rate capability (491 mAh/g at 5 A/g). The excellent electrochemical performance of our composite is attributed to the suppressed/accommodated volume expansion of Fe3O4 and formation of a stable solid electrolyte interphase (SEI) layer during lithiation/delithiation caused by unique multidimensional composite structure of Fe3O4-carbon tube-GNS with a continuous transport path for electrons and Li+. In addition, such the enhanced lithium storage of our composite is confirmed with the kinetic characterization at various scan rates by analyzing their storage and capacitive contributions.

Ultrafast Electron Dynamics in Coupled and Uncoupled HgTe Quantum Dots.

In this article, we study electron dynamics in HgTe quantum dots with a 1.9 μm gap, a material relevant for infrared sensing and emission, using ultrafast spectroscopy with 35 fs time resolution. Experiments have been carried out at several probing photon energies around the gap, which allows us to follow the relaxation path of the photoexcited electrons. We compare such dynamics in two kind of samples, HgTe quantum dots with long ligands and with short ligands, in order to distinguish the role of the coupling between adjacent quantum dots. Three main dynamics can be observed in the transient reflectivity on both samples, with slightly different relaxation times: two fast decays on the time scale of hundreds of femtoseconds and a few picoseconds, respectively, followed by a slower relaxation back to the unperturbed value over hundreds of picoseconds. The two fast components are associated with intraband relaxation of the photoexcited electrons within the conduction band, while the final relaxation path can be assigned to Auger relaxation mechanisms and to the slower interband exciton recombination.

Measurement of field emission array current distributions by metal-coated CMOS image sensors

A CMOS image sensor is utilized to determine the time- and spatially resolved distribution of the total electron emission current of a silicon field emission array. The sensor measures electron emission without the need for phosphorus screens or scintillators as converters. However, in initial experiments, rather low field emission currents of several hundreds of nanoamperes per emitter already damaged the sensor surface, which altered the systems’ signal response over the measurement time. In consequence, we coated the CMOS sensor surface with a Cu layer for surface protection. In contrast to the original insulating surface, Cu is an excellent current- and heat-conductor, which avoids lens charging by providing a conductive path for incident electrons and has an improved heat dissipation capability. Measurements using a segmented field emission cathode with four individually addressable tips demonstrate a consistent correlation between the emission current and the sensor signal of the metal-coated image sensor. Furthermore, the characterization of a field emission array showed that single tip emission currents of up to 12 μA per tip are measurable without discernible damage effects of the sensor’s surface.

Electronic Conduction Path Design in the Lithium-Ion Battery Electrodes Using Electrostatic Dry Coating Process

With the further spread of electric vehicles, lithium-ion batteries (LiBs) are required not only to improve battery performance but also to reduce manufacturing costs and CO2 emissions. Generally, the LiB electrodes are made by using slurry wet coating process, which involves solvent drying and recovery steps. There are problems such as high production costs and high CO2 emissions. As one means of solving these problems, solvent-free dry coating process is attracting attention. In addition, from the viewpoint of improvements in battery performance, the LiB electrodes have become thick to enhance the energy density of LiBs. However, thickening the electrodes substantially lengthens the ionic and electronic conduction paths within the electrode, leading to a substantial decrease in battery capacity. In this study, a dry coating process using an electrostatic field was investigated to improve both battery performance and productivity of the electrode manufacturing process. The electrostatic field was used for powder deposition (electrostatic printing) and particle orientation control. Particle orientation was particularly targeted at anisotropic conductive additives, and methods to orient them in the electrode thickness direction to form electronic conduction paths were investigated. Carbon fiber (fiber diameter: 11 μm, fiber: 70 μm) was added as a conductive additive and applied on the current-collector foil by electrostatic coating method together with other materials (active material, acetylene black, and binder) to orient the carbon fiber in the film thickness direction. To identify the process parameters for controlling the orientation of carbon fibers, we conducted orientation analysis of carbon fibers within the electrode using the three-dimensional structure obtained from X-ray computed tomography (CT). Furthermore, we investigated the effect of adding carbon fibers in the electrode and controlling orientation of them on battery performance through electrochemical evaluations. In this presentation, we will discuss in more detail the method of orientation control of carbon fibers using the electrostatic dry coating process, as well as the results analyzing the effects of adding and orientating carbon fibers on battery performance.

Effect of Positive Active Material De-Agglomeration on 350Wh/Kg Class High Energy Density Lithium Sulfur Laminated Batteries

In recent years, lithium-sulfur (Li-S) batteries have been widely developed as next generation secondary batteries for aircraft applications such as drones and HAPS (High Altitude Platform Station), which are requires high gravimetric energy density. In order to achieve the cell design of 350 Wh/kg class Li-S batteries, we should focus on these three steps.First, we need to develop elemental and process technologies to achieve the capacity close to the theoretical sulfur capacity. Second, we need to use an electrolyte that is sparsely soluble or insoluble in polysulfide. Thirdly, we have to minimize the components other than the active material. The cathode is conventionally composed sulfur in Ketjen black (KB) on aluminum foil current collector. However, this limits the capacity of about 1250 mAh/g. Additionally, increasing the thickness of the cathode is an effective method for minimizing the number of cathode substrates, however, it is difficult to balance the high sulfur loading amounts and the high-rate performances, due to a difficulty to make adequate Li ion and electron paths.1) Micro-porous carbon has been reported as a supporting material that can exhibit a capacity close to the theoretical sulfur capacity2), In this study, we focused on activated carbon (AC) manufactured by Kuraray, which is commercially available and has a proven track record of mass synthesis. We used it in combination with ultra-thin aluminum sheet, successfully achieving a 350 Wh/kg class Li-S laminated battery.S/AC composite was obtained by mixing sulfur and AC (YP-80F, Kuraray) with weight ratio of 60 : 40, followed by heating at 155 °C for 12 h. Afterward the of S/AC were de-agglomerated by using the energy ball milling (MM500nano, Retsch). S/AC cathode was fabricated by coating S/AC slurry (S/AC: carbon nanofiber (CNF) : binder = 92.5 :4 :3.5 by weight) on Al sheet. To assemble the cell, the cathode (S loading: 4.7 mg/cm2) was pressed to reduce its thickness by 34%. 5 Ah class laminated cell was prepared by stacking 10 sheets of the S/AC cathodes, 11 sheets of Li anodes, 20 sheets of a separator, and the electrolyte lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/lithium bis(fluorosulfonyl)imide (LiFSI) : sulfolane (SL) : hydrofluoroether (HFE) = 0.8/0.2: 1: 1.7 (molar ratio)). Electrochemical performances were tested with voltage range between 1.0 V – 3.3 V after activation process.Focusing on the de-agglomeration of the positive electrode active material, we investigated a dispersion process of S/AC composite to achieve a capacity close to the theoretical sulfur capacity. After preparing S/AC composite, the A/AC was de-agglomerated using the ball milling. Figure 1 shows the comparison of the capacity of dispersion phase A and B at each cycle. It was found that the dispersion treatment increases the initial capacity close to the theoretical capacity of 1672 mAh/g. Also, the dispersion treatment (phase B) increased the capacities up to the 15th cycle, compared with those without the treatment (phase A). This suggest that the well dispersed S/ACimproved the diffusion of Li ions.Furthermore, in order to increase the energy density of the battery, we adopted an ultra-thin Al current collector of 7 μm in thickness instead of the conventional 20 μm thick Al sheet, and using the above dispersion process, we fabricated a large 70 mm x 70mm Li-S laminated battery.Fig.2 shows its charge-discharge curve of a new designed Li-S battery. The first plateau, which is generally observed around 2.3 V in a conventional S/KB system, is not confirmed. This is a feature of micro-porous carbon system. The Li-S battery delivered a discharge capacity of 6.7 Ah, which is equal to 1632 mAh/g-S.Fig. 3 shows a comparison of battery weights by employing KB and AC. The capacity of S/KB is approximately 1150 mAh/g-S, which is smaller than that of the AC (1632 mAh/g-S). Therefore, the loading amount of the active material can be reduced by employing the AC instead of KB, resulting in reduction of the carbon constituting the complex at the same time. Consequently, a laminate-type battery with high capacity of 6.7 Ah, and energy density (351 Wh/kg, laminate film and tabs are excluded in this calculation) was achieved.In the presentation, I would like to discuss the effect of de-agglomeration of the S/AC composite. [References] [1]. H. Nara, et.al., J. Electrochem. Soc., 164, A5026–A5030 (2017).[2] S. Usuki, et. al., J. Electrochem. Soc., 85, 650–655 (2017). [Acknowledgement] This work was partly supported by Advanced Low Carbon Technology Research, Development Program Special Priority Research Area “Next-Generation Rechargeable Battery” (ALCA-Spring) from the Japan Science and Technology Agency (JST) (Grant Number JPMJAL1301). Figure 1

Capacity Recovery Phenomenon Manifested in Lithium-Ion Batteries Due to over-Discharge

【Background】 The need for Lithium-ion batteries (LIBs) with longer life is growing with the popularization of their applications, but LIBs lose capacity with use. These reduction in capacity of LIBs is mainly due to three factors: namely, the reduction of a positive electrode capacity, the reduction of a negative electrode capacity, and the mutual “capacity slippage” between the capacity of a positive and a negative electrodes [1]. The reduction of a positive and a negative electrode capacity is caused by deactivation of active materials due to decrease in the conducting paths of electrons and Li+. The capacity slippage is not only caused by the decreases in the capacity of a positive and a negative electrodes but also by deactivation of Li+. This Li+ deactivation is attributed to the formation of solid electrolyte interfaces and the immobilization of Li+ due to their trapping within a negative electrode [2, 3]. In this study, a method for recovering capacity by repeating short-term over-discharge was investigated, and the effect of this method on a LIB was evaluated. 【Experimental】 Laminated-type cells were fabricated by alternately stacking negative electrodes and positive electrodes. The positive and negative active materials were LiNi1/3Co1/3Mn1/3O2 and graphite, respectively. In the charge/discharge cycle test, the cells were charged and discharged at a constant current of 1 C between 3.0 V to 4.2 V at 50 oC. The rest time was 30 minutes. The capacity recovery treatment consisted of two steps at 25 oC. First, the cells were discharged at a constant current of 1 C until the cell voltage reached 2.5 V or 72 seconds had elapsed, followed by a rest period of 30 minutes, and the cycle was repeated until the behavior of the discharge curve did not change. Second, the cycle of discharging at a constant current of 10 C until the cell voltage reached 0.5 V or 1 second had elapsed and resting for 60/n minutes was repeated n times, where n is an integer from 3 to 6. 【Results & Discussion】 Figure 1a shows discharge capacity retention in the charge/discharge cycle tests with capacity recovery, and Figure 1b shows discharge curves at the specific cycles. Capacity recovery was performed after the 400th and specific cycles. As shown in Fig. 1a, the number of cycles at which the capacity retention fell bellow the value at the 400th cycle was extended by repeating the capacity recovery. As shown in Fig. 1b, because of performing capacity recovery after 400 cycles, the discharge capacity was recovered by 17.0 mAh, and the discharge curve at the 401st cycle is equivalent to that at the 100th cycle. To verify the origin of this capacity recovery, the discharge curve analysis [4] was carried out for these discharge curves. The results of discharge curve analysis are shown in Figures 2a and 2b. The horizontal axis shows discharge capacity, and the negative region is the surplus charge capacity. The vertical axis is the cell voltage and the potential of the positive and negative electrodes relative to lithium metal. The plots represent actual values during discharge, and the solid lines represent the potential curves of the positive and negative electrodes and the voltage curve of the cell plotted from the difference between them. According to the results of the analysis, the discharge endpoints of the negative electrode curves are located on the lower capacity side than the discharge endpoints of the positive electrodes. This result is due to capacity slippage and means the discharge endpoints of the negative electrode curves determine those of the cell curves. Focusing on the discharge endpoints of the negative electrode curves reveals that the position was shifted toward the higher capacity side by 17.6 mAh (from 201.6 to 219.2 mAh) owing to the capacity recovery. This value agrees well with 17.0 mAh which is the amount of recovery capacity obtained from the charge/discharge cycle tests shown in Fig. 1b. This agreement strongly suggests that the origin of the capacity recovery is the recovery of capacity slippage. On the day of the presentation, the mechanism by which capacity slippage is recovered will be discussed while the results of the disassembly analysis will be also introduced. [1] P. Ramadass et al., J. Power Sources, 112, 614 (2002).[2] H. J. Ploehn et al., J. Electrochem. Soc., 151, A456 (2004).[3] T. Yoshida et al., J. Electrochem. Soc., 153, A576 (2006).[4] K. Honkura et al., J. Power Sources, 264, 140 (2014). Figure 1

Construction of Cu-doped α-Fe2O3/γ-Fe2O3 hetero-phase junction composite and its photocatalytic performance

Chlortetracycline hydrochloride (CTC), a class of antibiotics, poses a significant environmental hazard, particularly in aquatic ecosystems. The advancement of highly efficient and readily recyclable materials for water treatment remains an important focus of research in environmental remediation. In this study, Cu-doped α-Fe2O3/γ-Fe2O3 hetero-phase junction materials were prepared by a solvothermal method and a controlled calcination process to enhance the photocatalytic degradation of CTC in water by Fe2O3. Experimental results indicate that the composite material has superior magnetic properties, with Cu2-α-Fe2O3/γ-Fe2O3, featuring a high specific surface area and small pores, showing the best CTC adsorption. The α-Fe2O3/γ-Fe2O3′s interlaced energy levels facilitate quick electron transfer, and copper ion addition optimizes electron paths, generating numerous oxygen vacancies. This, combined with the hetero-phase junction, boosts charge separation and migration. Among the samples tested, The Cu2-α-Fe2O3/γ-Fe2O3 composite demonstrated the most efficient photocatalytic performance, with a degradation rate of 90.19 % for CTC achieved under Visible Light Irradiation. The proposed second-order reaction rate constants were approximately 31.99, 10.07, and 4.48 times higher than those for α-Fe2O3, γ-Fe2O3, and α-Fe2O3/γ-Fe2O3, respectively. The material also demonstrates good degradation effects on other antibiotics (such as oxytetracycline, tetracycline hydrochloride, etc.). Moreover, the structural morphology of the sample remains stable after cycling. O2– and h+ are the main active species in the photocatalytic degradation process of CTC, while OH plays a secondary role. The possible degradation pathways were elucidated by calculating predicted free radical attack sites using density-functional theory (DFT) and by analyzing the products of the CTC degradation process. Additionally, the toxicity risk assessment indicates that the intermediate products have low toxicity and pose a minimal potential risk to the aquatic environment.

Construction of BiVO4/g-C3N4/Ag3PO4 ternary heterojunction with double Z-scheme and its photocatalytic and bacteriostatic properties

A novel Bi-composite photocatalyst BiVO4/g-C3N4/Ag3PO4 with a double Z-scheme structure was prepared by hydrothermal method assisted by honeysuckle extract. When the mass fraction of Ag3PO4 in the composite is 10 %, the inactivation rates of E.coli and S. aureus were 6.9 and 4.6 log, respectively. The MIC results were 0.6 and 0.8 mg/ml, respectively. The capture experiment confirmed that h+ and O2− were the main active substances that catalyzed bacteriostasis. Double Z heterojunction reduces the photochemical corrosion of Ag3PO4, changes the transmission path of photogenerated electrons, and then promotes the separation of photogenerated electron holes, thus obtaining significant photocatalytic activity.

Plasmonic properties of silicon nitride encapsulated copper

We investigated the optical properties (i.e. plasmonic loss) of thin-film copper that was deposited and processed in a 300mm CMOS pilot line. The optical properties at 1550 nm (QSPP,Cu = 3921 ± 350) were evaluated by measuring the propagation loss of dielectric loaded plasmonic waveguides on samples with high and low root mean square surface roughness (Rq) with and without a silicon nitride diffusion barrier and at room temperature and cryogenic temperatures. In our fabrication result, the average grain size is 2.08±0.05μm, which is much larger than the mean free path of free electrons in copper, so the surface roughness becomes the main cause of the waveguide propagation loss from the fabrication constrains. Further, we show that copper can be encapsulated by a 15 nm silicon nitride diffusion and oxidation barrier without degrading the optical properties.

A wearable cotton fiber-based supercapacitor electrode material with outstanding stability and photothermal performance utilizing AgNWs, NiCoAl-LDH, and PPy-NWs

Designing cotton fiber (CF) based flexible electrode materials with both electrochemical energy storage and structural stability is crucial for the utilization of flexible supercapacitors in wearable devices. Nevertheless, the electrochemical properties of such materials are often constrained by suboptimal ion diffusion, a limited electroactive surface area, and inadequate structural integrity. Herein, Silver nanowires (AgNWs), NiCoAl hydrotalcite (NCA-LDH), and polypyrrole nanowires (PPy-NWs) are employed to construct a CF-based electrode material (PNHAS/CF) with high stability through a layer-by-layer self-assembly method. The PNHAS/CF with a high capacitance of 1207.58 mF cm−2 at 5 mA cm−2 due to the faster electronic transmission paths of AgNWs and PPy-NWs, and the high specific capacitance of NCA-LDHs. The NCA-LDH stabilizes the PPy-NWs molecular chain, and the PPy-NWs winding structure can further enhance the PNHAS/CF's structural stability and prevent the AgNWs network from being destroyed, which guarantees the exceptional 87.5 % capacitance retention after 2000 cycles. The constructed symmetrical supercapacitor shows an energy density of 36.28 μWh cm−2 at 0.31 mW cm−2 power density. The PNHAS/CF exhibits superb solar spectral absorptivity (~94.8 %) and outstanding solar heating performance. Surprisingly, the fiber-based flexible electrode material and the assembled supercapacitor are expected to find applications in wearable intelligent electronics.

NiMn-Ag NWs complexes electrode material with in situ grown conductive 3D networks for enhanced supercapacitive performance by boosting Ni2+

Power density is one of the important factors affecting the performance of electrode materials, which is hampered by ion/electron transport and agglomeration build-up problems. In this study, a novel 3D NiMnO3/Ni(OH)2/Ag NWs composite is synthesized via the introduction of Ag NWs. The introduction of Ag NWs synergistically influences the crystal structure and micro-morphology of the NiMnO3/Ni(OH)2/Ag NWs composite. The unique pentatwinned structure of Ag NWs facilitates the enhancement of the (110) and (101) crystal planes, which induces the movement of Ni 2p3/2, leading to a significant increase of Ni2+ concentration in the composites. This ensures an abundance of ion adsorption sites, generating materials conducive to reactive activity. This new structure increases the density of active sites and establishes a conductive network, which optimizes the electron and ion transport paths, greatly reduces the diffusion resistance at the electrode-electrolyte interface, and improves the charge transfer efficiency, thus effectively increasing the specific capacity and energy density of the material. The NiMnO3/Ni(OH)2/Ag NWs//AC device exhibits a remarkable specific capacity of 350.478 mAh·g−1 at a current density of 0.01 A cm−2, and its Ragone plot reveals a peak energy density of 81.107 Wh kg−1 at a power density of 1699.871 W kg−1. Additionally, it achieves an energy density of 60.532 Wh kg−1 at a power density of 8490.072 W kg−1. This study explores the design and application of 3D structured electrode materials, which effectively improves the specific capacity of the materials and provides a new idea to further improve the energy density of supercapacitors.

Preventing Overrides of Severe Drug Allergy Alerts Initiative: an Implemented System Upgrade

Administering medications to patients with documented drug hypersensitivity reactions (DHR) poses a significant risk for adverse events, ranging from mild reactions to life-threatening incidents. Electronic healthcare systems have revolutionized the modern clinical decision-making process, with built in warnings. However, as these alerts become a routine part of healthcare provider’s workflow, alert fatigue becomes a challenge. This study was conducted within the Ministry of National Guard Health Affairs (MNGHA), a government healthcare system in Saudi Arabia. A taskforce of experts was formed to develop an electronic path that would prevent unintentional overrides of severe drug allergy alerts. The system underwent rigorous testing, and monitoring parameters were established. We outline the implementation of a system upgrade designed to trigger an alternative interruption in the computerized physician order entry (CPOE) process, distinct from the regular allergy pop-up alerts. The alternate path is activated upon a CPOE with a drug-to-drug match and a documented severe drug allergy symptom, necessitating co-signature form another prescriber before proceeding. The adopted upgrade is a proactive approach to enhance medication safety in electronic healthcare systems, ensuring that serious allergy-related warnings are not overridden, ultimately enhancing patient safety. Further monitoring will confirm the safety and effectiveness of this measure. This study provides a model for institutions seeking to prevent allergy-related harm within their patient population.

Plasmonic enhancement of Faraday rotation with gold nanodisks with low height-to-diameter aspect ratios

We investigate the Faraday rotation induced in gold nanodisks with low height-to-diameter aspect ratios. Through a systematic study, we analyze the phenomenon using electrostatic theory with the modified long-wavelength approximation. We show that the Faraday rotation is enhanced at the localized surface plasmon resonance when the nanodisk’s effective mean free path is equal to the mean free path of the conduction electrons in the bulk metal, where light absorption dominates over light scattering. We also show that the Faraday rotation is largely enhanced at shorter rather than longer wavelengths.

Tracing the electron transport behavior in quantum-dot light-emitting diodes via single photon counting technique

The electron injection and transport behavior are of vital importance to the performance of quantum-dot light-emitting diodes. By simultaneously measuring the electroluminescence-photoluminescence of the quantum-dot light-emitting diodes, we identify the presence of leakage electrons which leads to the discrepancy of the electroluminescence and the photoluminescence roll-off. To trace the transport paths of the leakage electrons, a single photon counting technique is developed. This technique enables us to detect the weak photon signals and thus provides a means to visualize the electron transport paths at different voltages. The results show that, the electrons, except those recombining within the quantum-dots, leak to the hole transport layer or recombine at the hole transport layer/quantum-dot interface, thus leading to the reduction of efficiency. By reducing the amount of leakage electrons, quantum-dot light-emitting diode with an internal power conversion efficiency of over 98% can be achieved.

Z-scheme heterojunction of TiO2/NH2-MIL-125(Ti) growing on carbon fibers cloth: Photocatalytic degradation of tetracycline and toxicity analysis

Photocatalysis stands out as a promising and eco-friendly method for antibiotics removal, yet traditional photocatalysts, mainly in powder form, are often prone to detachment and loss, making them difficult to recycle and reuse. In this work, we address this challenge by using carbon fiber (CF) cloth with a large area as a carrier for catalysts. To improve the photocatalytic efficiency, we synthesized TiO2 nanorods on the surfaces of CF cloth and incorporate NH2-MIL-125 (Ti) on them, thus the Z-scheme heterojunctions CF/TiO2/NH2-MIL-125(Ti) was obtained. In order to fully understand the structural properties and performance advantages of CF/TiO2/NH₂-MIL-125 (Ti) composites, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray photoelectron spectroscopy (XPS), UV–visible diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), Brunauer-Emmett-Teller (BET), Mott-Schottky (M-S) and valence band X-ray photoelectron spectroscopy (VB-XPS). Due to the special electronic transmission path of the Z-scheme heterojunctions, the CF/TiO2/NH2-MIL-125(Ti) composite achieve 95.30 % degradation of tetracycline (TC) within 210 min. The composite also shows exceptional reusability, with a degradation rate of 93.55 % maintained even after four cycles. Finally, we proposed a pathway and catalytic process for the decomposition of TC by CF/TiO2/NH2-MIL-125(Ti) and performed toxicity assessments of TC and its precursors using T.E.S.T. software. This novel photocatalyst composite offers a green and efficient approach for treating antibiotic wastewater, presenting a significant advancement in environmental remediation strategies.

Si particle size blends to improve cycling performance as negative electrode for all-solid-state lithium-ion battery

Silicon negative electrodes dramatically increase the energy density of lithium-ion batteries (LIBs), but there are still many challenges in their practical application due to the limited cycle performance of conventional liquid electrolyte systems. In this study, we clarified that the use of an inorganic solid electrolyte improves the cycle performance of the LIB with the Si negative electrode and the size of Si particles influenced the properties of the all-solid-state LIB. The all-solid-state LIB using micro-sized silicon (mSi) particles as the negative electrode active material showed a large initial discharge capacity (2400 mAh g-1), but the discharge capacity decreased as charge/discharge cycles increased. In contrast, the all-solid-state LIB using nano-sized silicon (nSi) particles showed a low initial discharge capacity (1000 mAh g-1), but the discharge capacity increased for the initial 20 charge/discharge cycles. The cross-sectional images analyzed by scanning electron microscopy showed that for mSi particles, cracks and voids occurred due to volumetric changes during charging and discharging, interrupting the flow path of ions and electrons, whereas for nSi particles, the contact with the solid electrolyte and conductive material was improved. Moreover, the all-solid-state LIB using the negative electrode of nSi: mSi = 7: 3 (mass ratio) showed higher initial discharge capacity and longer cycle performance than that using mSi and nSi.

Carbon Nanotubes Connecting and Encapsulating MoS2-Doped SnO2 Nanoparticles as an Excellent Lithium Storage Performance Anode Material.

Doping and carbon encapsulation modifications have been proven to be effective methods for enhancing the lithium storage performance of batteries. The hydrothermal method and ball milling are commonly used methods for material synthesis. In this study, a composite anode material rich in carbon nanotubes (CNTs) conductive tubular network connection and encapsulation of SnO2-MoS2@CNTs (SMC) was synthesized by combining these two methods. In this highly conductive network, nano-SnO2 particles are uniformly dispersed and embedded in MoS2 with a layered structure, and the obtained SnO2-MoS2 composite material is tightly connected and encapsulated by the tubular network of CNTs. It is worth noting that the incorporation of layered MoS2 not only effectively anchors the SnO2 nanoparticles, but also provides a broader space for lithium-ion movement due to the larger interlayer spacing. The conductive network of CNTs shortens the diffusion path of electrons and Li+ and provides more diffusion channels. The reversible capacity of the SnO2-MoS2@CNTs nanocomposite material remains at 1069.3 mA h g-1 after 320 cycles at 0.2 A g-1, and it exhibits excellent long-term cycling stability, maintaining 904.5 mA h g-1 after 1000 cycles at 1.0 A g-1. The composite material demonstrates excellent pseudocapacitive contribution rate performance, with a contribution rate of 87% at 2.0 mV s-1. The results indicate that SnO2-MoS2@CNTs has excellent electrochemical lithium storage performance and is a promising anode material for lithium-ion batteries.

The electron resistance of a single skyrmion within ballistic approach

An alternative way of skyrmion quasi-particle detection is simulated at low voltage bias. The point contact (PC), attached to the strip with a Néel-type skyrmion, can detect it with a higher efficiency than a magnetic tunnel junction. The method is based on detecting the skyrmion via the ballistic magnetoresistance ratio (BRR). PC's resistance with skyrmion significantly differs from the one without it. BRR is estimated in the framework of the point contact model for two directions of spin-polarized current: perpendicular to the transport direction (case 1) and along one (case 2). Skyrmion's size is assumed to be around 3.6 nm in diameter—smaller, or comparable, to the mean free path of electrons, allowing it to utilize the ballistic transport approach. As a result, resistance values for the considered Néel type skyrmion within the related size are estimated as 157 Ω for case 1 and 452.2 Ω for case 2 with optimistic BRR 101.3% and 291.7%, respectively. BRR for case 2 is higher due to the spin-filtering effect. The method also has the potential to detect the skyrmion type, or other magnetic nano structures such as bimeron, domain wall (DW), etc.