Active Ions Research Articles

Performance evolution of alkali-activated phosphorus slag paste filling material: Effect of hemihydrate phosphogypsum content

The stockpiling issues of phosphorus slag (PS) and hemihydrate phosphogypsum (HPG) have become vital technical obstacles limiting the economic development of enterprises. The synergistic substitution of PS and HPG for ordinary Portland cement in preparing alkali-activated phosphorus slag paste filling material (AAPS-PM) is essential to realize the high-value utilization of PS and HPG and reduce carbon emissions. HPG was selected as a sulfate activator for this research due to its metastable qualities and chemical composition benefits. The effect of HPG on the properties of AAPS-PM was systematically investigated by setting time, fluidity, strength development, water resistance, and pore solution pH experiments. The evolution of hydration products and pore size characteristics was elaborated employing X-ray diffractometer (XRD), scanning electron microscopy (SEM) and low-field nuclear magnetic resonance (NMR). The results demonstrated that the addition of HPG displayed remarkable procoagulant thickening characteristics on AAPS-PM. Additionally, HPG was conducive to developing early uniaxial compressive strength (UCS), whereas 90% content of HPG had a negative impact on the enhancement of later UCS. The softening coefficient and water absorption exhibited duality with 80% HPG content as the critical point, obtaining a maximum value of 0.73 and a minimum value of 6.63%, respectively. It is noteworthy that the decrease in pore solution pH was primarily correlated with the acidity carried by HPG. Herein, the alkali activator accelerated the depolymerization of PS vitreous and generated H3SiO4- and H3AlO42- and Al(OH)63-. Furthermore, the active ions combined with Ca2+ and SO42- supplied by HPG, which contributed to the formation of dihydrate gypsum, ettringite and C-(A)-S-H gels. Encouragingly, microscopic analysis confirmed the macroscopic performance changes of AAPS-PM. The gel network created by the interweaving of hydration products refined the pore structure and improved the microstructure morphology, which is the primary source of mechanical strength. Nevertheless, the high content of HPG provided a driving force for the development of capillary pores, resulting in a rapid reduction in later strength. Overall, this research can contribute new ideas to the large-scale integrated disposal of solid waste.

Spray-dried ternary bioactive glass microspheres: Direct and indirect structural effects of copper-doping on acellular degradation behavior

Silicate-based bioactive glass nano/microspheres hold significant promise for bone substitution by facilitating osteointegration through the release of biologically active ions and the formation of a biomimetic apatite layer. Cu-doping enhances properties such as pro-angiogenic and antibacterial behavior. While sol-gel methods usually yield homogeneous spherical particles for pure silica or binary glasses, synthesizing poorly aggregated Cu-doped ternary glass nano/microparticles without a secondary CuO crystalline phase remains challenging. This article introduces an alternative method for fabricating Cu-doped ternary microparticles using sol-gel chemistry combined with spray-drying. The resulting microspheres exhibit well-defined, poorly aggregated particles with spherical shapes and diameters of a few microns. Copper primarily integrates into the microspheres as Cu0 nanoparticles and as Cu2+ within the amorphous network. This doping affects silica network connectivity, as calcium and phosphorus are preferentially distributed in the glass network (respectively as network modifiers and formers) or involved in amorphous calcium phosphate nano-domains depending on the doping rate. These differences affect the interaction with simulated body fluid. Network depolymerization, ion release (SiO44−, Ca2+, PO43−, Cu2+), and apatite nanocrystal layer formation are impacted, as well as copper release. The latter is mainly provided by the copper involved in the silica network and not from metal nanoparticles, most of which remain in the microspheres after interaction. This understanding holds promising implications for potential therapeutic applications, offering possibilities for both short-term and long-term delivery of a tunable copper dose. Statement of significanceA novel methodology, scalable to industrial levels, enables the synthesis of copper-doped ternary bioactive glass microparticles by combining spray-drying and sol-gel chemistry. It provides precise control over the copper percentage in microspheres. This study explores the influence of synthesis conditions on the copper environment, notably Cu0 and Cu2+ ratios, characterized by EPR spectroscopy, an aspect poorly described for copper-doped bioactive glass. Additionally, copper indirectly affects silica network connectivity and calcium/phosphorus distribution, as revealed by SSNMR. Multiscale characterization illustrates how these features impact acellular degradation in simulated body fluid, highlighting the therapeutic potential for customizable copper dosing to address short- and long-term needs.

Behavior of Microstrain in Nd3+-Sensitized Near-Infrared Upconverting Core-Shell Nanocrystals for Defect-Induced Tailoring of Luminescence Intensity.

In an attempt to optimize the upconversion luminescence (UCL) output of a Nd3+-sensitized near-infrared (808 nm) upconverting core-shell (CS) nanocrystal through deliberate incorporation of lattice defects, a comprehensive analysis of microstrain both at the CS interface and within the core layer was performed using integral breadth calculation of high-energy synchrotron X-ray (λ = 0.568551 Å) diffraction. An atomic level interpretation of such microstrain was performed using pair distribution function analysis of the high-energy total scattering. The core NC developed compressive microstrain, which gradually transformed into tensile microstrain with the growth of the epitaxial shell. Such a reversal was rationalized in terms of a consistent negative lattice mismatch. Upon introduction of lattice defects into the CS systems upon incorporation of Li+, the corresponding UCL intensity was maximized at some specific Li+ incorporation, where the tensile microstrain of CS, compressive microstrain of the core, and atomic level disorders exhibited their respective extreme values irrespective of the activator ions.

Enhanced sodium-storage performances of crumpled MXene nanosheets via alkali treatment–induced active ammonium ions

Ti3C2Tx MXene demonstrates excellent potential as an anode material for sodium-ion capacitors. However, the narrow interlayer spacing and self-stacking phenomenon limit its applicability. In this study, we demonstrate an easy two-step method involving freezing and crumpling of MXene nanosheets to improve their Na-ion storage via the addition of ammonium ions (referred to as FCM nanosheets). Flat MXene particles aggregate and undergo folding in an alkaline solution. Ammonium ions can penetrate the gaps between MXene nanosheets, expanding interlayer spaces and inducing the formation of folds. Compared to MXene nanosheets, FCM nanosheets exhibit improved ion transfer kinetics and additional high capacity owing to the intercalated ammonium ions. The manufactured FCM anode exhibits remarkable electrochemical properties, including a high specific capacity of 313 mAhg−1 and stability over 15,000 cycles.

Study on Water Splitting of the 214-Type Perovskite Oxides LnSrCoO4 (Ln = La, Pr, Sm, Eu, and Ga).

We present a study on the electrocatalysis of 214-type perovskite oxides LnSrCoO4 (Ln = La, Pr, Sm, Eu, and Ga) with semiconducting-like behavior synthesized using the sol-gel method. Among these five catalysts, PrSrCoO4 exhibits the optimal electrochemical performance in both the oxygen evolution reaction and the hydrogen evolution reaction, mainly due to its larger electrical conductivity, mass activity, and turnover frequency. Importantly, the weak dependency of LSV curves in a KOH solution with different pH values, revealing the adsorbate evolving mechanism in PrSrCoO4, and the density functional theory (DFT) calculations indicate that PrSrCoO4 has a smaller Gibbs free energy and a higher density of states near the Fermi level, which accelerates the electrochemical water splitting. The mutual substitution of different rare-earth elements will change the unit-cell parameters, regulate the electronic states of catalytic active site Co ions, and further affect their catalytic performance. Furthermore, the magnetic results indicate strong spin-orbit coupling in the electroactive sites of Co ions in SmSrCoO4 and EuSrCoO4, whereas the magnetic moments of Co ions in the other three catalysts mainly arise from the spin itself. Our experimental results expand the electrochemical applications of 214-type perovskite oxides and provide a good platform for a deeper understanding of their catalytic mechanisms.

Mechanical properties and microstructure of lime-treated shield tunnel muck improved with carbide slag and soda residue

Shield tunnel muck are usually discarded due to high water content and poor engineering properties, resulting in occupation of land sources and waste of soil sources. Meanwhile, large amounts of industrial waste such as carbide slag (CS) and soda residue (SR) are landfilled with a low reuse rate, which poses a threat to the natural environment. This study aims to improve waste shield tunnel muck using CS and SR and traditional lime, and the improved tunnel muck is expected to be used in subgrade filling to provide a new approach to solve this dilemma. A series of physical, mechanical, subgrade property, and microcosmic tests were conducted on shield tunnel muck improved by CS, SR and lime. The effects of different mixing proportions on the properties of improved tunnel muck were examined. The micro-improvement mechanisms of CS and SR on tunnel muck were explored. Results indicate that the addition of CS or SR can effectively improve the physical and mechanical properties of shield tunnel muck. CS plays a significantly role than SR in improving physical and mechanical properties of tunnel muck. A synergistic enhancement is observed as the combined CS and SR are added, and the optimal mixing proportion of tunnel muck to CS to SR is found to be 100:6:2 with a fixed lime content of 4 %. The alkaline environment created by the synergistic action of CS and SR promotes the dissolution of the active ions in soils, and the generated crystals and gelling products of hydration significant contribute to soil improvement. The tunnel muck improved with appropriate CS or SR content could meet the requirements for light or medium traffic load levels and can be effectively utilized as subgrade filling.

Enhanced prelithiation performance of Li5FeO4 cathode additive and optimized solid electrolyte interface enabled by Mn substitution

In the pursuit of enhancing the energy density of lithium-ion batteries, cathode prelithiation emerges as a pivotal approach, introducing additional irreversible active lithium ions to augment performance. Li5FeO4 (LFO) stands out as an excellent option, boasting an impressive theoretical specific capacity and the additional advantages of cost-effectiveness in raw materials and low preparation cost. However, the impact of extra lithium incorporations on compositional changes at the electrode-electrolyte interface as well as on cell stability has impeded further researches. Herein, a Mn doping strategy is proposed and predicted by first-principles calculations to synthesize partially Mn-substituted Li5.125Fe0.875Mn0.125O4 (LFMO). And the prelithiation with LFMO improved the interfacial composition of LiFePO4 (LFP) batteries compared to LFO, achieving a charging capacity of 213 mAh∙g−1 in the first cycle at 0.05 C. The subsequent treatment demonstrated superior cycling stability, maintaining a discharge specific capacity as high as 155.3 mAh∙g−1 after 100 cycles at 0.2 C, and exhibiting a higher capacity retention in the full cell. These discoveries could contribute to enhancing the regulation of battery interface during the utilization of LFO, potentially promoting the development of cathode lithium additives.

Spectral diagnosis of underwater microsecond high-current pulsed discharge plasma

Underwater microsecond high-current pulsed discharge can generate powerful shock waves and a significant number of active ions, offering a wide range of applications. To analyse the characteristics of plasma channel formed by the discharge, this study established a comprehensive test platform and conducted spectral diagnosis for underwater high-current pulsed discharge. Considering the randomness of the pulsed arc discharge, the voltage and current waveforms under different discharge cases were measured, and the images and emission spectra of the plasma channel were obtained. The origin of the continuous emission of the initial spectra was analysed. A spectral fitting algorithm was proposed, which could separate the spectral lines into line emission of Hα and continuous background, and correct the self-absorption. The time-varying characteristics of electron density were obtained under three typical discharge cases, the possible errors caused by baseline shift were considered, and the influencing factors of line broadening were analysed. Under the test conditions of this study, the electron density of plasma channel was in the order of 1024–1025 m−3.

Multi-vacancy synergistic effect in a NiSe0.4S1.6/ZnO heterostructure for promoting photocatalytic hydrogen production

Defect engineering is one of the methods to improve catalytic activity of photocatalysts, but there are few reports on multi-vacancy systems. In this paper, S doping NiSe2 (NiSe0.4S1.6, NSS) was synthesized and further the NSS/xZnO heterostructures containing Ni, Se and O vacancies were constructed. The hydrogen and active oxygen ions are in situ generated at oxygen vacancy (VO) in ZnO, which greatly reduce the recombination of photocarriers, and the generated active oxygen ions and sacrificial agent anions (S2−, SO32−) involve in the regeneration of oxygen vacancy, which may be one of the reasons for the high activity and stability of the composite catalysts. The polarization electric field is formed by regulating the selenium and nickel double vacancy (VSe, VNi) generated by doping NiSe2 with S, which further improves the charge separation leading to the promotion of photocatalytic hydrogen production. The synergistic effect of the three types of vacancies and the redox properties of the composite catalyst lead to a high H2 production rate of 17.04 mmol·g−1·h−1, 54 and 76 times higher than NSS and ZnO, and a high apparent quantum yield of 15.30 % at 400 nm. The hydrogen production mechanism was explored by EPR, Mott-Schottky, VB-XPS, in suit XPS, DFT, etc. This work proves that the combination of transition metal oxides with rich oxygen defects and metal chalcogenides with metal and chalcogen di-vacancies containing local polarized electric fields is an effective strategy to design high active photocatalyts for water splitting.

Theoretical Study on The Effect of Metal Ions on The Structural Properties of Base

Metal ions play an important role in living organisms, for example Mg2+ is a cofactor for many biological enzymes (including DNA and RNA synthesis), Ca2+ is an important component of bone composition, and metal ions such as Fe, Co, Zn, Ni and Cu also play an important role in the normal functioning of living organisms. One of the main targets of metal ions in living organisms is deoxyribonucleic acid (DNA), which is an important carrier of information stored and transmitted by organisms. The direct interaction between DNA base pairs and metal ions have a significant impact on the structure and function of DNA base pairs, which is demonstrated as following: the binding of metals to bases usually breaks the hydrogen bonds of the base pairs. The N7 atom of a purine residue or the N3 atom of a pyrimidine residue, as well as the outer ring O atom and the phosphate oxygen atom, are the preferred sites for metal binding. The binding of metals to DNA and RNA also indirectly affects the conformation of the sugar ring. REDOX active metal ions have the ability to bind to DNA and can mediate oxidative DNA damage by reacting with endogenous oxidants. According to studies of antioxidants in the field of metal-mediated oxidative DNA damage, metal ion coordination also plays a key role in the mechanism of some antioxidants. Also, metal-DNA interactions are the basis for many anti-cancer drugs, anti-viral drugs and anti-bacterial agents. Metal-mediated oxidative DNA damage is associated with a variety of diseases and conditions, and understanding the binding interactions and subsequent reactivity can facilitate the management or prevention of oxidative damage. It can be seen that the study of the effect of metal ions on the structural properties of DNA bases has far-reaching implications, providing a theoretical basis for the development of novel anticancer drugs, DNA-based metal nanodevice technologies and the fabrication of spectroscopic and reactive probes.

Lead species formation on pure hemimorphite surface and its performance for subsequent sulfidization

Hemimorphite is important-supplementary resource for the commercial zinc production, but it easy loses into tailings due to extreme difficulty for its surface sulfidization. Adding active metal ions after sulfidization have been widely proposed for enhancing hemimorphite floatability, but its desired efficiency in flotation practice has not yet been completely achieved caused by the instability of sulfide layer. Whereas pre-adsorption of active metal ions to modify the hemimorphite surface has strong potential to make up for this shortcoming. Herein, the feasibility and appropriate environment of free Pb<sup>2+</sup> for modifying the pure hemimorphite surface was evaluated. Subsequently, the performance of Pb<sup>2+</sup> adsorption for enhancing sulfidization stability and floatability of hemimorphite were investigated. The X-ray photoelectron spectroscopy results indicated that the Pb<sup>2+</sup> adsorption on hemimorphite surface was achieved through the Pb ions displacement for Zn ions, and it was bond to oxygen-containing groups on hemimorphite surface. Such adsorption was strengthened with the increasing of solution pH, owing to the abundant Pb hydroxyl species precipitated on mineral under alkaline conditions, in term of the results of visual MINTEQ modeling and time-of-flight secondary-ion mass spectrometry. In addition, the X-ray photoelectron spectroscopy results showed dominant Pb hydroxyl species further reacted with sulfur during subsequent sulfidization to generate much more S species than that of without Pb<sup>2+</sup> pre-modification. Meanwhile, such sulfide layer composed by Pb<sup>2+</sup> on the mineral surface presented much higher stability than Zn-S species, which was verified via adsorption and desorption tests. As a result, the sulfidization and flotation recovery of hemimorphite increased after Pb<sup>2+</sup> pre-adsorption.

Molten salt shielding synthesis of Er3+/Yb3+ co-doped La9W6O30Cl phosphors for optical temperature sensing

Oxychloride phosphors that contain active ions coordinated with both oxygen and chloride ions have garnered significant attention, but the application of oxychloride phosphors is yet limited because of their demanding synthesis condition of vacuum or reducing atmosphere. Herein, we synthesize a new serial oxychlorides of La9W6O30Cl (LWOC) and Er3+/Yb3+, Ho3+/Yb3+, Tm3+/Yb3+ doped LWOC through molten salt shielding method (MSS) in air, which is more efficient compared to the traditional method in vacuum. The compound of LWOC crystallizes in the tetragonal system space group P42/nmc (No. 137) with cell parameters a = b = 10.0445(1) Å, c = 12.6826(4) Å, V = 1279.57(5) Å3 and Z = 11. The asymmetric unit of LWOC includes three La atoms, one unique W atom, two disordered W atoms with occupancy factors of 0.16(5) and 0.84(5), respectively, one Cl atom and six O atoms. Under the excitation of 980 nm laser, all the Er3+/Yb3+, Ho3+/Yb3+ and Tm3+/Yb3+ co-doped LWOC phosphors have excellent upconversion (UC) luminescence with bright visible light emission. A fluorescence intensity ratio (FIR) type temperature sensor is developed by using LWOC: Er3+, Yb3+ phosphor as sensing media, which has a maximum relative temperature sensitivity (Sr) of 0.90 % K−1 at 300 K.

Unraveling Broadband Near-Infrared Luminescence in Cr3+-Doped Ca3Y2Ge3O12 Garnets: Insights from First-Principles Analysis.

In this study, we conducted an extensive investigation into broadband near-infrared luminescence of Cr3+-doped Ca3Y2Ge3O12 garnet, employing first-principles calculations within the density functional theory framework. Our initial focus involved determining the site occupancy of Cr3+ activator ions, which revealed a pronounced preference for the Y3+ sites over the Ca2+ and Ge4+ sites, as evidenced by the formation energy calculations. Subsequently, the geometric structures of the excited states 2E and 4T2, along with their optical transition energies relative to the ground state 4A2 in Ca3Y2Ge3O12:Cr3+, were successfully modeled using the ΔSCF method. Calculation convergence challenges were effectively addressed through the proposed fractional particle occupancy schemes. The constructed host-referred binding energy diagram provided a clear description of the luminescence kinetics process in the garnet, which explained the high quantum efficiency of emission. Furthermore, the accurate prediction of thermal excitation energy yielded insights into the thermal stability of the compound, as illustrated in the calculated configuration coordinate diagram. More importantly, all calculated data were consistently aligned with the experimental results. This research not only advances our understanding of the intricate interplay between geometric and electronic structures, optical properties, and thermal behavior in Cr3+-doped garnets but also lays the groundwork for future breakthroughs in the high-throughput design and optimization of luminescent performance and thermal stability in Cr3+-doped phosphors.

Surface coating engineering of prelithiation cathode additives for lithium-ion batteries

The active lithium ions loss during the initial charge and discharge process of lithium ion batteries seriously hampers its increasement of energy density. Pre-lithiation, involving the pre-storage of active lithium ions prior to cycling, emerges as a promising and effective strategy to offset this loss. Li6CoO4 has been identified as a candidate capable of releasing adequate lithium ions to compensate for such loss. However, its poor air stability renders it susceptible to side reactions in the atmosphere, leading to the formation of residual lithium and consequently affecting its electrochemical performance. In this study, we propose application of a lithium aluminate (LiAlO2) coated onto the surface of lithium cobalt oxide (Li6CoO4) to mitigate the presence of residual lithium. Meanwhile, with decreasing of residual lithium, the rate capability is also enhanced. The research results demonstrate that samples treated with this coating layer exhibit an enhanced energy density in the full cell, indicating the efficacy of this approach in optimizing the electrochemical performance of prelithiation additives.

Experimental and theoretical investigation on the high activity La0.8-xSr0.2KxMn1-yByO3-δ perovskite catalyst with combined A and B site modifications

In this work, a series of LaMnO3 (LM) perovskite catalysts modified at A and B sites were prepared to accelerate soot combustion. The La0.68Sr0.2K0.12Mn0.9Cu0.1O3-δ (LSK0.12MCu0.1) modified by Sr, K and Cu has good catalytic activity and cycle stability, the presence of NO can obviously promote the oxidation of soot. A variety of characterization results show that doping the A and B sites of perovskite will not destroy the original structure of perovskite, and the doped ions (Sr2+, K+, and Cu2+) can enter the perovskite catalyst well, which may be conducive to the formation of more oxygen defects and active oxygen species. According to the DFT calculation, adding Sr and K to the A sites can alter how atoms interact in a perovskite catalyst, increase the amount of unsaturated coordination bonds, and encourage the development of high-valence active ions (Mn4+) and oxygen defects. The doping of transition metal to the B sites results in the formation of the Cu-O-Mn link, which forms the Mn(Cu)O6 octahedron and stimulates the development of oxygen vacancies and the release of active oxygen. This study will provide an important reference for developing non-precious metal-based perovskite materials with high activity and low cost for catalytic combustion.

External and internal stimuli for enhanced supercapacitor performance

Use of internal and external stimuli can be an alternative tool to address the limitations of a supercapacitor for its enhanced electrochemical properties. Influence of internal stimuli, such as redox active dopants and vacancies, can alter the electronic structure or phase of the electrode material, leading to an improved redox behavior of the pseudo-capacitors by virtue of electron polarizations, leading to a better electrochemical charge transfer kinetics. On the other hand, external stimuli, such as applied magnetic field, can alter the diffusion characteristics of the active ions in the electrolyte, thereby changing the ion/charge rearrangement and ion diffusion characteristics within supercapacitor electrodes. This Perspective emphasizes the importance of these two aspects, supported by an in-depth literature review to give a comprehensive overview of internal and external stimuli effects in designing the model systems for future electrochemical applications.

Trivalent dysprosium activated LaSr2AlO5 nanophosphors for NUV-excited wLEDs: Insights into structural, optical, Judd-Ofelt parameters and temperature dependent photoluminescence

Gel-combustion (GC) methodology was implemented in the present research to produce a series of single phase Dy3+ doped LaSr2AlO5 nanophosphors for the usage in wLEDs. X-ray powder diffraction patterns verified the phase purity and crystal structure of the produced materials. The XRD inspection supported the successful fabrication of tetragonal structured (I4/mcm space group) phosphors and revealed good accordance with card number 70–2197 on the JCPDS database. We collected diffuse reflectance spectra (DRS) to examine how doping affects the band gap. Furthermore, energy-dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM) have been employed for assessing elemental composition and surface morphology. On 349 nm excitation, LaSr2AlO5:Dy3+ phosphors produce the distinctive yellow PL emissions causedby 4F9/2→6H13/2 transition. Using excitation spectra, the Judd-Ofelt (J-O) characteristic (Ω = 2, 4, 6) have been determined. The Dy3+ transition's features show that the J-O parameters followed the trend which suggested an asymmetric environment around the ligand. The electric dipole transition predominated in the luminescence spectrum, causing the LaSr2AlO5:Dy3+ phosphor to emit a yellowish whitecolor. The fundamental mechanism for the energy transfer and concentration quenching instances among activator ions was discovered to be dipole-quadrupole interactions. Temperature dependent luminescence showed that the synthesized phosphors had thermal stability up to 523 K with activation energy of 0.1312 eV. The future prospects of the synthesized phosphor as an effective choice for near-ultraviolet-activated wLEDs are substantially supported by current comprehensive research.

Heterokaryotic transition-metal dimers embedded monolayer g-C3N3 as promising anchoring and electrocatalytic materials for lithium-sulfur battery: First-principles calculations

g-C3N3 not only has high content of pyridine nitrogen, but also has a special two-dimensional porous structure, which is an ideal diatomic catalytic host materials. In this work, homonuclear and heteronuclear dual-atom catalysts (DACs, TM-TM@g-C3N3, TM = Mn, Fe, Co, Ni) were constructed using single-layer g-C3N3 as the carrier material of DACs, and their potential as sulfur-hosting materials and electrocatalytic materials for lithium-sulfur batteries was explored through first principles comprehensively. The results show that the coupling between the two metal atoms in heteronuclear DACs can regulate the spin state of each other's d-electrons, so that the anchoring and catalytic effects of heteronuclear DACs on polysulfide are more excellent than that of homonuclear DACs. Co-Mn@g-C3N3, when utilized as the cathode material in lithium-sulfur batteries, offers exceptional properties due to the hybridization between Mn2+ high-spin state d electron and Co2+ half-filled dz2 orbital. This unique interaction not only enables the polysulfide to exhibit the lowest Gibbs free energy during conversion, but also results in the lowest reaction energy barrier of 0.26 eV for the conversion of Li2S2 to Li2S. Furthermore, it is found that when 3d transition metal atoms act as heteronuclear DACs, the coupling between metal ions with high-spin states at the active site and metal ions with empty orbitals or half-full d-electrons has the most significant catalytic effect on polysulfides.

Gold capped mesoporous bioactive glass guides bone regeneration via BMSCs recruitment and drug adaptive release

Recruiting endogenous stem cells and achieving controlled drug release are crucial for in situ bone regeneration. However, it remains challenging to design functional platforms that can effectively recruit stem cells and deliver drugs at an appropriate dose and a time-dependent manner under specific stimulus conditions. Herein, mesoporous bioactive glass (MBG), nanoreservoirs of the simvastatin (Sim), was end-capped with E7 peptide-modified gold nanoparticles (Au-NPs). This unique design allowed for effective recruitment of endogenous stem cells and enabled the sustained release of simvastatin. The released simvastatin facilitated the osteogenic differentiation of stem cells, supporting bone-like tissue reconstruction. Meanwhile, under near-infrared light irradiation, MBG@Sim-Au-E7 exhibited adaptive degradation and sustained release of simvastatin and active ions. This capability regulated the osteogenic microenvironment, further facilitating bone regeneration. In addition, the results of in vivo experiments showed that the healing of skull defect was significantly improved by MBG@Sim-Au-E7 after NIR irradiation. These findings highlight the potential of MBG@Sim-Au-E7 as a promising approach for preparing functional bone healing materials.

A functional cathode sodium compensation agent for stable sodium-ion batteries

Hard carbon (HC) is widely used in sodium-ion batteries (SIBs), but its performance has always been limited by low initial Coulombic efficiency (ICE) and cycling stability. Cathode compensation agent is a favorable strategy to make up for the loss of active sodium ions consumed by HC anode. Yet it lacks agent that effectively decomposes to increase the active sodium ions as well as regulate carbon defects for decreasing the irreversible sodium ions consumption. Here, we propose 1,2-dihydroxybenzene Na salt (NaDB) as a cathode compensation agent with high specific capacity (347.9 mAh g−1), lower desodiation potential (2.4–2.8 V) and high utilization (99%). Meanwhile, its byproduct could functionalize HC with more CO groups and promotes its reversible capacity. Consequently, the presodiation hard carbon (pHC) anode exhibits highly reversible capacity of 204.7 mAh g−1 with 98% retention at 5 C rate over 1000 cycles. Moreover, with 5 wt% NaDB initially coated on the Na3V2(PO4)3 (NVP) cathode, the capacity retention of NVP + NaDB|HC cell could increase form 36%–89% after 1000 cycles at 1 C rate. This work provides a new avenue to improve SIBs reversible capacity and cycling performance through designing functional cathode compensation agent.