Cation Diffusion Research Articles

Controlling the Phase Distribution of Single Bromide Quasi-2-Dimensional Perovskite Crystals via Solvent Engineering for Pure-Blue Light-Emitting Diodes.

To achieve pure-blue emission (460-470 nm), we manipulate the crystallization process of the quasi-2D perovskite, (PBA)2Csn-1PbnBr3n+1, prepared by a solution process. The strategy involves controlling the distribution of "n" phases with different bandgaps, solely utilizing changes in the precursor's supersaturation to ensure that the desired emission aligns with the smallest bandgap. Adjustments in photoluminescence (PL) wavelength are made by changing the solute concentration and solvent polarity, as these factors heavily influence the diffusion of cations, a crucial determinant for the value of "n". Subsequently, we enhance the PL quantum yield from 31 to 51% at 461 nm using trioctylphosphine oxide (TOPO) as an additive of antisolvent, which passivates halide vacancy and promotes orderly crystal growth, leading to faster carrier transfer between phases. With these strategies, we successfully demonstrate pure-blue LEDs with a turn-on voltage of 3.3 V and an external quantum efficiency of 5.5% at an emission peak of 470 nm with a full-width at half-maximum of 31 nm.

Disentangling Competitive and Synergistic Chemical Reactivities During the Seeded Growth of High-Entropy Alloys on High-Entropy Metal Sulfide Nanoparticles.

The seeded growth of one type of nanoparticle on the surface of another is foundational to synthesizing many multifunctional nanostructures. High-entropy nanoparticles that randomly incorporate five or more elements offer enhanced properties due to synergistic interactions. Incorporating high-entropy nanoparticles into seeded growth platforms is essential for merging their unique properties with the functional enhancements that arise from particle-particle interactions. However, the complex compositions of high-entropy materials complicate the seeded growth process due to competing particle growth and chemical reactivity pathways. Here, we design and synthesize a 36-member nanoparticle library to identify and disentangle these competitive interactions, ultimately defining chemical characteristics that underpin the seeded growth of high-entropy alloys on high-entropy metal sulfide nanoparticles. As a model system, we focus on (Cu,Zn,Co,In,Ga)S-SnPdPtRhIr, which combines a high-entropy metal sulfide semiconductor with a high-entropy alloy catalyst. We study the seeded growth of all possible pairwise combinations of Sn, Pd, Pt, Rh, Ir, and SnPdPtRhIr on the metal sulfides Cu1.8S, ZnS, Co9S8, CuInS2, CuGaS2, and (Cu,Zn,Co,In,Ga)S, which have comparable morphologies and sizes. Through these studies, we uncover unexpected chemical reactivities, including cation exchange, redox reactions, and diffusion. Reaction temperature, threshold reduction potentials, metal/sulfide chemical reactivity, and the relative strengths of the various bonds that could be formed during particle growth emerge as the primary factors that underpin seeded growth. Finally, we disentangle these competitive and synergistic chemical reactivities to generate a reactivity map that provides practical guidelines for achieving seeded growth in compositionally complex systems.

Evidence for NMR Relaxation Enhancement in a Protic Ionic Liquid by the Movement of Protons Independent of the Translational Diffusion of Cations.

The molecular dynamics, thermal stability, and ionic conductivity were studied in the protic ionic liquid 1-methylimidazolium bis(trifluoromethylsulfonyl)imide ([MIm][TFSI]). The relaxation of the 1H spin-lattice of cations in the measured frequency range (10 kHz to 20 MHz) and temperature (298 to 343 K) is sensitive mainly to slow processes occurring in the molecular dynamics of protic ionic liquid and dominated by the contribution of intermolecular translational diffusion. Molecular rotations give only a constant contribution and become significant in the higher frequency range. An interesting feature is the observed enhancement of the 1H spin-lattice relaxation below 0.03 MHz attributed to the exchange of protons (order of 10-5 s) between imidazolium cations. The measurements of the self-diffusion coefficient of hydrogen atoms of cation from 298 to 343 K additionally confirm the observed phenomenon. The coefficient for exchangeable protons -NH is higher than for the cation. The nuclear magnetic resonance (NMR) experiments provide unambiguous evidence for proton transport decoupled from molecular diffusion of ions and support the conclusion that the charge transport mechanism in the studied PIL includes contributions from both the vehicular and Grotthus mechanisms. The protic ionic liquid is thermally stable to about 573 K as shown by thermogravimetric analysis and its electrical conductivity is 5 × 10-2 S/cm at 423 K.

Genome Sequence Resource of Bacillus mojavensis KRS009, a Rhizospheric Microorganism with Biocontrol Potential

Bacillus mojavensis KRS009 was identified as an antagonistic strain with a strong inhibitory effect on various phytopathogenic fungi. To provide further insight into its biocontrol mechanisms and ability to improve plant salt tolerance, the high quality complete genome of KRS009 was sequenced by PacBio platform and assembled using PacBio-HiFiReads. The KRS009 genome consists of one circular chromosome of 4,089,687 bp with 43.5% GC content and 4,062 open reading frames, of which 3,920 protein-coding genes, 86 transfer RNA, 10 ribosomal RNA, and 26 small RNA were identified in this genome. Among them, genes related to compatible solutes, including treC, galU, proX, and proW, are involved in the synthesis of trehalose, proline, and betaine metabolism and play an important role in relieving osmotic stress. In addition, the KRS009 genome contains genes associated with high salinity tolerance, including those responsible for Na+/H+ antiporters, K+ transporters, TrkH thiamin phosphate synthase, K+-sensing histidine kinase, aryl-phospho-beta-D-glucosidase, flavoprotein CzcO associated with the cation diffusion facilitator CzcD, and chaperonin GroEL. Together, the high-quality genome resource of strain KRS009 would provide a molecular basis for further research on its biocontrol and plant salt tolerance mechanisms. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Determination of Sodium Ion Diffusion Coefficient in Tin Sulfide@Carbon Anode Material Using GITT and EIS Techniques

The electroanalytical behavior of SnSx (x = 1, 2) encapsulated into a carbon phase was studied using the galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS). These techniques are widely utilized in battery systems to investigate the diffusion of alkali metal cations in anode and cathode materials depending on the concentration of ions in the host material. Here, we report different calculation methods showing how the applied model affects the derived diffusion coefficient. The calculated value of the apparent chemical diffusion coefficient of sodium ions (DNa+) is in the range of 1 × 10−10 to 1 × 10−15 cm2/s depending on the technique, mathematical protocol, geometry of the electrode material, and applied potential.

Structural and chemical evolutions of a magnesium vanadium oxide cathode under electrochemical cycling in magnesium batteries

The design of cathode materials that remain chemically and structurally stable during repetitive ion insertion and extraction poses a significant challenge in developing multivalent batteries. The cycling stability of traditional metal oxide-based cathode is challenged by sluggish diffusion of multivalent cations and parasitic reactivity at interfacial regimes, including the cathode electrolyte interphase layer (CEI). Understanding the reactions at the cathode-electrolyte interface, particularly those induced by non-stoichiometric surface layers, is a crucial design parameter for both cathode materials and electrolytes. In this study, we employed multimodal analysis, including in situ and ex situ X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS) to examine the surface reactions and subsequent structural and chemical evolutions of the CEI on high voltage magnesium vanadium oxide (MgV2O4) spinel cathode during the Mg2+ insertion/extraction processes. The results revealed that the presence of non-stoichiometric surface layers in the magnesium vanadium oxide cathode drive the decomposition of bis(trifluoromethanesulfonyl)imide (TFSI-) anion, leading to the formation of the CEI layer. The CEI layer could inhibit the Mg2+ ion transfer processes. Accompanying this reactivity-driven degradation, the magnesium vanadium oxide cathode undergoes pulverization, forming clusters of nanosized particles. This process likely improves cycling ability by creating new intercalation sites and shortening the diffusion pathway for the Mg2+ cations. This study demonstrates that controlling surface stoichiometry and engineering morphological properties are critical design parameters for high performance cathodes for multivalent batteries.

Molecular evolution and functional diversification of metal tolerance protein families in cereals plants and function of maize MTP protein

Plants employ metal tolerance proteins (MTPs) to confer tolerance by sequestering excess ions into vacuoles. MTPs belong to the cation diffusion facilitator (CDF) family, which facilitates the transport of divalent transition metal cations. In this study, we conducted a comprehensive analysis of the MTP gene families across 21 plant species, including maize (Zea mays). A total of 247 MTP genes were identified within these plant genomes and categorized into distinct subgroups, namely Zn-CDF, Mn-CDF, and Fe/Zn-CDF, based on phylogenetic analyses. This investigation encompassed the characterization of genomic distribution, gene structures, cis-regulatory elements, collinearity relationships, and gene ontology functions associated with MTPs. Transcriptomic analyses unveiled stress-specific expression patterns of MTP genes under various abiotic stresses. Moreover, quantitative RT-PCR assays were employed to assess maize MTP gene responses to diverse heavy metal stress conditions. Functional validation of metal tolerance roles was achieved through heterologous expression in yeast. This integrated evolutionary scrutiny of MTP families in cereals furnishes a valuable framework for the elucidation of MTP functions in subsequent studies. Notably, the prioritized MTP gene ZmMTP6 emerged as a positive regulator of plant Cd tolerance, thereby offering a pivotal genetic asset for the development of Cd-tolerant crops, particularly maize cultivars.

Electric field/current enhanced grain growth behavior of 8mol% Y2O3 stabilized cubic ZrO2 (8Y-CSZ) polycrystals

The effect of the flash event on grain growth behavior was examined in 8 mol% yttria-stabilized cubic zirconia (8Y-CSZ) polycrystals under direct and alternating electric fields/currents. Even at the same specimen temperature, the rate of the grain growth is accelerated in the flash event than in the heat treatment without electric field/current (0 V), suggesting that the non-thermal effect caused additionally under the flash event contributes to the acceleration of the grain growth. Although the grain growth behavior can be characterized by the empirical equation (dtn –d0n = kt) with the same grain growth exponent of n = 3 irrespective of the electric field/current, the activation energy for the grain growth is lowered under the flash event. This suggests that the non-thermal effect caused by the flash event does not affect the mechanism of the grain growth, but would accelerate the rate-controlling process of the grain growth. The non-thermal effects can be further accelerated in fine-grained specimens under the alternating current flash and/or by increasing the input power density. Since the grain growth is rate-controlled by the grain boundary cation diffusivity, the non-thermal effect under the flash event would accelerate the grain boundary cation diffusivities through the formation of excess oxygen vacancies depending on the polarity and the power density.

High-performance lithium batteries achieved by electrospun MXene-Enhanced cation-selective membranes

Conventional separators applied in lithium batteries face limitations like low porosity, poor electrolyte wettability, lower cation selectivity, and thermal instability, which impact battery performance and safety characteristics. Besides the challenge in separator design, transition metal ion migration from positive electrodes during cycling greatly accelerates capacity fading because of unrestricted diffusion of transition metal cation across the separator. This study explores an innovative strategy for the separator design by incorporating MXene (spraying MXene solution on both sides of the separator), a two-dimensional material, into electrospun Polyacrylonitrile/Polyetherimide membranes with the function of cation selection. Li+ can be accelerated, and its transference number increases along with the anion limitation in the MXene layer. Ni, Co, and Mn ion dissolution from the positive electrode is inhibited due to the cation selectivity of the MXene layer. Leveraging electrospinning advantages, the resultant membranes exhibit high porosity, excellent liquid absorption, mechanical strength, and superior thermal properties. Benefiting from MXene's layered structure and excellent adsorption ability, the membrane significantly inhibits the dissolution of transition metal ions while enabling smooth lithium deposition due to its cation selectivity. Eventually, the Li||NMC811 batteries deliver outstanding cyclic performance (91.3 % capacity retention after 200 cycles) and robust lithium dendrite suppression (800 h of stable cycling). Moreover, the MXene-modified membrane demonstrates exceptional electrolyte wettability, significantly improving ionic transference number (0.67) and conductivity (1.6 mS/cm). Modification of membrane surfaces with MXene offers insights into addressing transition metal ion migration from the positive electrode material perspective, providing a promising avenue for high-performance LIBs.

A Membrane-Free Rechargeable Seawater Battery Unlocked by Lattice Engineering.

Seawater batteries that directly utilize natural seawater as electrolytes are ideal sustainable aqueous devices with high safety, exceedingly low cost, and environmental friendliness. However, the present seawater batteries are either primary batteries or rechargeable half-seawater/half-nonaqueous batteries because of the lack of suitable anode working in seawater. Here, a unique lattice engineering to unlock the electrochemically inert anatase TiO2 anode to be highly active for the reversible uptake of multiple cations (Na+, Mg2+, and Ca2+) in aqueous electrolytes is demonstrated. Density functional theory calculationsfurther reveal the origin of the unprecedented charge storage behaviors, which can be attributed to the significant reduction of the cations diffusion barrier within the lattice, i.e., from 1.5 to 0.4eV. As a result, the capacities of anatase TiO2 with 2.4% lattice expansion are ≈100 times higher than the routine one in natural seawater, and ≈200 times higher in aqueous Na+ electrolyte. The finding will significantly advance aqueous seawater energy storage devices closer to practical applications.

Cation Distribution and Anion Transport in the La3Ga5-xGe1+xO14+0.5x Langasite Structure.

Exploration of compositional disorder using conventional diffraction-based techniques is challenging for systems containing isoelectronic ions possessing similar coherent neutron scattering lengths. Here, we show that a multinuclear solid-state Nuclear Magnetic Resonance (NMR) approach provides compelling insight into the Ga3+/Ge4+ cation distribution and oxygen anion transport in a family of solid electrolytes with langasite structure and La3Ga5-xGe1+xO14+0.5x composition. Ultrahigh field 71Ga Magic Angle Spinning (MAS) NMR experiments acquired at 35.2 T offer striking resolution enhancement, thereby enabling clear detection of Ga sites in different coordination environments. Three-connected GaO4, four-connected GaO4 and GaO6 polyhedra are probed for the parent La3Ga5GeO14 structure, while one additional spectral feature corresponding to the key (Ga,Ge)2O8 structural unit which forms to accommodate the interstitial oxide ions is detected for the Ge4+-doped La3Ga3.5Ge2.5O14.75 phase. The complex spectral line shapes observed in the MAS NMR spectra are reproduced very accurately by the NMR parameters computed for a symmetry-adapted configurational ensemble that comprehensively models site disorder. This approach further reveals a Ga3+/Ge4+ distribution across all Ga/Ge sites that is controlled by a kinetically governed cation diffusion process. Variable temperature 17O MAS NMR experiments up to 700 °C importantly indicate that the presence of interstitial oxide ions triggers chemical exchange between all oxygen sites, thereby enabling atomic-scale understanding of the anion diffusion mechanism underpinning the transport properties of these materials.

Influence of cationic vacancy diffusion on the aging behavior of low-temperature SrCo1-xRuxO3 thermosensitive ceramics

The thermosensitive ceramics of negative temperature coefficient (NTC), SrCo1-xRuxO3 (0 ≤ x ≤ 0.8), were synthesized using the solid-phase method. The research systematically explored the phase structure, microstructure, elemental chemical states, electrical properties, and aging performance. X-ray diffraction (XRD) data indicates that with the increase of Ru content, the lattice parameter increases. Scanning electron microscopy (SEM) images reveal a dense and uniform microstructure. X-ray photoelectron spectroscopy (XPS) data indicates the presence of Co2+/Co3+ and Ru4+/Ru5+ ion pairs. Resistive temperature data indicates its potential use as a low-temperature thermosensitive resistance material in the range of 2–300 K. Fitting the resistance-temperature curve using the thermally activated band conduction model and Mott's 3D variable range hopping model. Proposed the Ru–O2--Co hopping model, elucidating the hole hopping transport mechanism in NTC ceramics. Impedance spectroscopy analysis indicates that grain boundary resistance dominates the overall resistance of the sample. After aging at 77 K for 864 h, the maximum aging drift rate of the ceramic material is 1.55 %. Proposed a novel cationic vacancy diffusion model to explain aging phenomena, offering a new perspective for designing high-stability low-temperature NTC thermistors.

Exhaustive Study of Electrical Conductivity in the MNb2−x TixO6–0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites

The CaNb2O6 and ZnNb2O6 columbites (Sp.gr. Pbcn) were studied as oxygen ion conductors both theoretically and experimentally. A theoretical approach included geometrical-topological analysis, bond valence site energy (BVSE) and density functional theory (DFT) calculations. The BVSE approach showed the possibility of pure oxygen ions diffusion with migration energies less than 0.45 eV in both compounds. However, DFT calculations indicated the possibility of diffusion of both anions and cations. The single-phases columbites were synthesized by the Pechini method for accurately determine charge carriers type and investigated by impedance spectroscopy, by the Tubandt method, which confirmed the absence of cationic conductivity, and measured the electrical conductivity as a function of oxygen partial pressures. The CaNb2O6 sample was characterized by the pure oxygen-ionic conductivity ∼2 × 10−6 S cm–1 at 800 °C (E a = 0.82 eV), while the ZnNb2O6 had a similar conductivity value due to mixed ionic-electronic contribution (E a = 0.83 eV). The electromotive force method also showed the predominance of the ionic type of conductivity in CaNb2O6, while ZnNb2O6 has a mixed conductivity with ion transport number of about 0.4. Additionally, we synthesized Ti-doped samples MNb2−x Ti x O6–0.5x (M = Mg, Ca; x = 0.1, 0.2) to study the doping effect on conducting properties.

Study on the mechanism of interaction between cations and the surface of nano-SiO2 particle in the salt solution by using molecular dynamics simulation

Nano-SiO2 solution has great potential for application in the field of oil and gas exploration and development. However, its application is restricted due to the aggregation of nano-SiO2 in stratum water. This paper studies the process of interaction between nano-SiO2 particles and salt solutions by using the molecular dynamics simulation experiments, including the characteristics of transportation and diffusion of cations around the nano SiO2, the effect of cations on the recombination and destruction of hydrogen bonds, the interaction energy between cations and nano SiO2. The main results are as follows. During the transportation and diffusion of cations in the solution, the hydrogen bonds of water molecules are broken, so that the hydrogen bonds can be rearranged, and a stable solvated layer can be formed. In the solvated layer, the repulsive force of solvation can prevent the charge exchange between cation and the charged surface of nano SiO2 particle. Compared with the monovalent salt solution, more divalent cations can break through the solvation layer to generate the charge exchange on the surface of nano-SiO2 particle. More divalent cations can conduct small amplitude oscillation movement near the surface of nano-SiO2 particle due to the strong electrostatic effect. When the concentration of salt solution is increased (3000 mg/L → 7000 mg/L) and the valence of cations is increased (monovalent → bivalent), the hydrogen bond is easier to break through the solvation layer to gather on the surface of nano SiO2 particles, which is unfavorable to the stability of nano SiO2 particles. When the cations transport to the position of 7 Å away from the surface of nano-SiO2 particles, the short-range force (including hydrogen bond force, van der Waals force, and electrostatic force) begins to affect the movement of cations. When the cations transport to the position of 2 ∼ 3 Å away from the surface of nano-SiO2 particles, the charge exchange occurs between cations and the surface of nano SiO2 particle, so that the local energy is increased and the cation continues to oscillate. In summary, with the increasing of concentration of salt solution and the valence state, more cations can break through the solvation layer to be adsorbed on the surface of nano SiO2 particle, showing that the ability of transportation and diffusion of cations is weakened, the interaction energy between nano SiO2 particle and salt solution molecules is enhanced. The electrostatic force is the main force to destroy the stability of nano SiO2 particle. The conclusions can provide a certain theoretical basis for the efficient application of nano-SiO2 materials in the field of oil and gas exploration and development and other interrelated industry.

Designing a Magnesium/Sodium Hybrid Battery Using Hierarchical Iron Selenide Architecture as Cathode Material and Modified Dual-Ion Salts in Ether as Electrolyte.

We developed a magnesium/sodium (Mg/Na) hybrid battery using a hierarchical disk-whisker FeSe2 architecture (HD-FeSe2) as the cathode material and a modified dual-ion electrolyte. The polarizable Se2- anion reduced the Mg2+ migration barrier, and the 3D configuration possessed a large surface area, which facilitated both Mg2+/Na+ cation diffusion and electron transport. The dual-ion salts with NaTFSI in ether reduced the Mg plating/stripping overvoltage in a symmetric cell. The hybrid battery exhibited an energy density of 260.9 Wh kg-1 and a power density of 600.8 W kg-1 at 0.2 A g-1. It showed a capacity retention of 154 mAh g-1 and a Coulombic efficiency of over 99.5% under 1.0 A g-1 after 800 long cycles. The battery also displayed outstanding temperature tolerance. The findings of 3D architecture as cathode material and hybrid electrolyte provide a pathway to design a highly reliable Mg/Na hybrid battery.

Development of a physical reservoir that operates by the diffusion of Cu cations

We developed a physical reservoir using Cu2S and Cu-doped Ta2O5 as a material of a reservoir layer, in both of which Cu cations contribute to the reservoir operation. The reservoirs showed nonlinearity and short-term memory required as reservoirs. The memory capacity becomes maximum with the input frequency at around 104 Hz. The t-distributed stochastic neighbor embedding analysis revealed that a Cu2S reservoir can classify input of five bit pulse trains, and a Cu-doped Ta2O5 reservoir can classify input of six bit pulse trains. These are longer than four bit pulse trains that a Ag2S island network reservoir achieved in our previous study. Using the superior performance, NARMA task was also carried out.

Enhanced Li+ and Mg2+ Diffusion at the Polymer–Ionic Liquid Interface within PVDF‐Based Ionogel Electrolytes for Batteries and Metal‐Ion Capacitors

AbstractWith the widespread use of batteries, their increased performance is of growing in importance. One avenue for this is the enhancement of ion diffusion, particularly for solid‐state electrolytes, for different ions such as lithium (Li+) and magnesium (Mg2+). Unraveling the origin of better cation diffusion in confined ionic liquids (ILs) in a polymer matrix (ionogels) is compared to that of the IL itself. Ionic conductivity measured by electrochemical impedance spectroscopy for ionogels (7.0 mS cm−1 at 30 °C) is very close to the conductivity of the non‐confined IL (8.9 mS cm−1 at 30 °C), that is, 1‐ethyl‐3‐methyimidazolium bis(trifluorosulfonyl)imide (EMIM TFSI). An even better ionic conductivity is observed for confined EMIM TFSI with high concentrations (1 m) of lithium or magnesium salt added. The improved macroscopic transport properties can be explained by the higher self‐diffusion of each ion at the liquid‐to‐solid interface induced by the confinement in a poly‐vinylidenedifluoride (PVDF) polymer matrix. Upon confinement, the strong breaking down of ion aggregates enables a better diffusion, especially for TFSI anion and strongly polarizing cations (e.g., Li+, Mg2+.). The coordination number of these cations in the liquid phase confirmed that Li+ and Mg2+ interact with the polymer matrix. Moreover, it is a major result that the activation energy for diffusion is lowered.

Influence of magnetic field upon electrode kinetics and ionic transport

Performance properties in lithium-ion, sodium-ion, and zero excess metal batteries are currently limited by the sluggish ion diffusion and inhomogeneity of the transport ion flux, resulting in poor formation, low rates, and short cycle lives. In this work, a magnetic field is applied to the cell by the incorporation of a NdFeB magnetic spacer, and the effect upon the kinetics and transport properties at each electrode is studied using galvanic charge and discharge, electrochemical impedance spectroscopy, and intermittent titration techniques. Stabilization of the anode-free or zero excess sodium and lithium metal cells is achieved during formation, and upon cycling. Reduced cell overpotential is observed with resulting higher areal capacities, with improved ionic diffusion through the electrode. Upon cycling metallic dendritic structures are suppressed due to the inhomogeneity of ion flux, and the likely competing kinetics of plating at a metallic tip and the surrounding surface. At the NMC electrode, improved kinetics are observed with lower charge-transfer resistance (Rct) due to the reshaped and aligned domain in the ferromagnetic Ni of NMC cathode. Pulsed current methods further confirm enhanced cationic diffusion in the anode graphite materials, particularly at high mass loading of 4 mA h cm−2 and high C rates. Consequently, the combination of enhanced reaction kinetics on the ferromagnetic cathode and improved diffusion kinetics in the porous anode leads to excellent full-cell performance compared to control groups. This study highlights the potential of magnetic fields in enhancing diffusion and reaction kinetics for rechargeable batteries (Li, Na, K, Mg, etc.), and may provide routes for extending cycle life, reconditioning cells, and improving formation protocols.

Designing Atomic Interface in Sb2S3/CdS Heterojunction for Efficient Solar Water Splitting.

In the emerging Sb2S3-based solar energy conversion devices, a CdS buffer layer prepared by chemical bath deposition is commonly used to improve the separation of photogenerated electron-hole pairs. However, the cation diffusion at the Sb2S3/CdS interface induces detrimental defects but is often overlooked. Designing a stable interface in the Sb2S3/CdS heterojunction is essential to achieve high solar energy conversion efficiency. As a proof of concept, this study reports that the modification of the Sb2S3/CdS heterojunction with an ultrathin Al2O3 interlayer effectively suppresses the interfacial defects by preventing the diffusion of Cd2+ cations into the Sb2S3 layer. As a result, a water-splitting photocathode based on Ag:Sb2S3/Al2O3/CdS heterojunction achieves a significantly improved half-cell solar-to-hydrogen efficiency of 2.78% in a neutral electrolyte, as compared to 1.66% for the control Ag:Sb2S3/CdS device. This work demonstrates the importance of designing atomic interfaces and may provide a guideline for the fabrication of high-performance stibnite-type semiconductor-based solar energy conversion devices.

One-Step Hydrothermal Synthesis of NVO Cathodes with Varied Lattice NH4 + Content: Effect on Structural Evolution and Electrochemical Performance.

Aqueous zinc ion batteries have been extensively researched due to their distinctive advantages such as low cost and high safety. Vanadium oxides are important cathode materials, however, poor cycle life caused by vanadium dissolution limits their application. Recent studies show that the lattice NH4 + in vanadium oxides can act as a pillar to enhance structural stability and play a crucial role in improving its cycling stability. Nevertheless, there is still a lack of research on the effect of the lattice NH4 + content on structural evolution and electrochemical performance. Herein, we synthesize vanadium oxides with different contents of lattice NH4 + by a one-step hydrothermal reaction. The vanadium oxides with lattice NH4 + exhibit high initial capacity, as well as good cycling stability and rate performance compared to bare vanadium oxide. Combined with electrochemical analyses, ex-situ structural characterizations, and in-situ X-ray diffraction tests, we reveal that the lattice NH4 + content plays a positive role in vanadium oxides' structural stability and cation diffusion kinetics. This work presents a direction for designing high-performance vanadium cathodes for aqueous zinc ion batteries.