Revealing Hydrogen Bond Effect in Rechargeable Aqueous Zinc-Organic Batteries.

The surrounding hydrogen bond (H-bond) interaction around the active sites plays indispensable functions in enabling the organic electrode materials (OEMs) to fulfill their roles as ion reservoirs in aqueous zinc-organic batteries (ZOBs). Despite important, there are still no works could fully shed its real effects light on. Herein, quinone-based small molecules with a H-bond evolution model has been rationally selected to disclose the regulation and equilibration of H-bond interaction between OEMs, and OEM and the electrolyte. It has been found that only a suitable H-bond interaction could make the OEMs fully liberate their potential performance. Accordingly, the 2,5-diaminocyclohexa-2,5-diene-1,4-dione (DABQ) with elaborately designed H-bond structure exhibits a capacity of 193.3 mA h g-1 at a record-high mass loading of 66.2 mg cm-2 and 100% capacity retention after 1500 cycles at 5 A g-1. In addition, the DABQ//Zn battery also possesses air-rechargeable ability by utilizing the chemistry redox of proton. Our results put forward a specific pathway to precise utilization of H-bond to liberate the performance of OEMs.

A Cu/MnOx Composite with Copper-Doping-Induced Oxygen Vacancies as a Cathode for Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries are anticipated to be the next generation of important energy storage devices to replace lithium-ion batteries due to the ongoing use of lithium resources and the safety hazards associated with organic electrolytes in lithium-ion batteries. Manganese-based compounds, including MnOx materials, have prominent places among the many zinc-ion battery cathode materials. Additionally, Cu doping can cause the creation of an oxygen vacancy, which increases the material's internal electric field and enhances cycle stability. MnOx also has great cyclic stability and promotes ion transport. At a current density of 0.2 A g-1, the Cu/MnOx nanocomposite obtained a high specific capacitance of 304.4 mAh g-1. In addition, Cu/MnOx nanocomposites showed A high specific capacity of 198.9 mAh g-1 after 1000 cycles at a current density of 0.5 A g-1. Therefore, Cu/MnOx nanocomposites are expected to be a strong contender for the next generation of zinc-ion battery cathode materials in high energy density storage systems.

A highly reversible force-assisted Li - CO2 battery based on piezoelectric effect of Bi0.5Na0.5TiO3 nanorods.

The use of light-assisted cathode is regarded as an effective approach to reduce the overpotential of lithium carbon dioxide (Li - CO2) batteries. However, the inefficient electron-hole separation and the complex discharge-charge reactions hamper the efficiency of CO2 photocatalytic reaction in battery. Herein, a highly reversible force-assisted Li - CO2 battery has been established for the first time by employing a Bi0.5Na0.5TiO3 nanorods piezoelectric cathode. The high-energy electron and holes generated by the piezoelectric cathode with ultrasonic force can effectively enhance the carbon dioxide reduction reaction (CDRR) and carbon dioxide evolution reaction (CDER) kinetics, thereby reducing the overpotentials during the discharge-charge processes. Moreover, the morphology of the discharge product (Li2CO3) can be modified via the dense surface electrons of the piezoelectric cathode, resulting in the promoted decomposition kinetics of Li2CO3 in charging progress. Thus, the force-assisted Li - CO2 battery with the unique piezoelectric cathode can adjust the output and input energy by ultrasonic wave, and provides an ultra-low charging platform of 3.52 V, and exhibits excellent cycle stability (a charging platform of 3.42 V after 100 h cycles). The investigation of the force-assisted process described herein provides significant insights to solve overpotential in the Li - CO2 batteries system.

Optimization Strategy in Hydrogen Storage Performance of Ti─V─Cr─Mn Alloys via LiAlH4.

V-based solid solution materials hold a significant position in the realm of hydrogen storage materials because of its high hydrogen storage capacity. However, the current dehydrogenation temperature of V-based solid solution exceeds 350 °C, making it challenging to fulfill the appliance under moderate conditions. Here advancements in the hydrogen storage properties and related mechanisms of TiV1.1 Cr0.3 Mn0.6  + x LiAlH4 (x = 0, 5, 8, 10 wt.%) composites is presented. According to the first principle calculation analysis, the inclusion of Al and Li atoms will lower the binding energy of hydride, thus enhancing the hydrogen absorption reaction and significantly decreasing the activation difficulty. Furthermore, based on crystal orbital Hamilton population (COHP) analysis, the strength of the V─H and Ti─H bonds after doping LiAlH4 are reduced, leading to a decrease of the hydrogen release activation energy (Ea ) for the V-based solid solution material, thus the hydrogen release process is easier to carry out. Additionally, the structure of doped LiAlH4 exhibits an outstanding hydrogen release rate of 2.001 wt.% at 323 K and remarkable cycling stability.

Analysis of Online Recruitment Intention Among 543 Hospitals: A Comprehensive Investigation of Influencing Factors and Current Situation.

Objective: The primary objective of this study was to investigate the current state of online recruitment intention among hospitals and identify its key influencing factors. This research aims to provide valuable insights that can guide the development of recruitment and employment strategies for hospital departments and student management. Methods: This study employed a cross-sectional survey approach involving 543 hospitals. Data collection utilized both convenient offline recruitment methods and online recruitment information platforms. A total of 543 questionnaires were distributed, resulting in the collection of 543 valid responses. The participating hospitals comprised 225 tertiary hospitals and 318 secondary hospitals. Additionally, the sample included 430 general hospitals, 113 psychiatric hospitals, dental hospitals, and 406 specialized hospitals. Geographically, 137 hospitals were located in urban counties or towns. Furthermore, 333 hospitals targeted undergraduate graduates, while 210 focused on graduate students. Results: The analysis of the data revealed several significant findings. Among the included hospitals in the sample, 19.71% expressed online recruitment intention for candidates with neurasthenia. Factors contributing to a higher online recruitment intention among hospitals included a preference for recruiting undergraduates (P = .011), the belief that online recruitment is suitable for clinical positions (P = .002), challenges in assessing candidates' expertise online (P = .002), concerns about dishonesty in online recruitment (P = .028), and the perception that online recruitment requires less technical expertise for hospitals (P < .001). Conclusions: This study highlights the multifaceted nature of online recruitment intention within hospitals. The identified influential factors emphasize the need for customized strategies in recruitment and employment. Medical university recruitment and employment departments should adopt tailored measures that align with the unique dynamics of online recruitment to address these factors effectively. In this way, hospitals can enhance their recruitment processes and ensure the selection of candidates that meet their specific requirements.

A dendrite-free and anticaustic Zn anode enabled by high current-induced reconstruction of the electrical double layer.

Aqueous Zn-based batteries deliver thousands of cycles at high rates but poor recyclability at low rates. Herein, we reveal that this illogical phenomenon is attributed to the reconstructed electrode/electrolyte interface at high rates, wherein the condensed electrical double layer (EDL) and the tightly absorbed Zn2+ ions on the Zn electrode surface afford compact and corrosion-resistant Zn deposits.

Mesoporous Gold Film with Surface Sulfur Modification to Enable Dendrite-Free Lithium Plating/Stripping for Long-Life Lithium Metal Anodes.

The formation of a lithiophilic phase is an effective method to inhibit the growth of lithium dendrites and obtain high-performance Li metal anodes (LMAs). Nonetheless, previous studies have overlooked the underlying mechanistic studies that modulate the structure of the lithiophilic phase as well as lithiophilicity. A self-supporting sulfur-modified mesoporous gold film on nickel foam (SMGF@NF) for LMAs is created with mesoporous structure, which can provide sufficient active sites for uniform lithium deposition. The synergistic promotion of lithiophilic gold and sulfur leads to uniform lithium nucleation and induces consistent lithium removal during lithium stripping. The doping of S promotes the decomposition of bistrifluoromethanesulfonimide lithium salt to generate lithium fluorde, thus forming a more stable solid electrolyte interface. Combining the multifaceted advantages of SMGF@NF, its lithium-plated electrode can achieve ultralong cycle life in symmetrical batteries (over 1000 h at 0.5 mA cm-2 and 1 mAh cm-2 ) and ultralow overpotential (≈10 mV). Meanwhile, the Li-SMGF@NF||LiFePO4 full cell achieves a high cycling performance and rate capability (92.4% capacity retention after 1000 cycles at 5 C). The study probes into the composite electrode surface composition and structure, revealing the mechanism of high-performance LMAs.

In Situ Alloying Sites Anchored on an Amorphous Aluminum Nitride Matrix for Crystallographic Reorientation of Zinc Deposits.

Secondary aqueous zinc-ion batteries (ZIBs) are considered as one of the promising energy storage devices, but their widespread application is limited by the Zn dendrite issues. In this work, we propose a rational design of surface protective coatings to solve this problem. Specifically, a silver (Ag) nanoparticle embedded amorphous AlN matrix (AlN/Ag) protective layer is developed. The former would alloy in situ with Zn to form AgZn3 alloy sites, which subsequently induce the Zn deposition with preferred (002) facets. The latter can effectively alleviate the structural expansion during repeated Zn plating/stripping. Consequently, the delicately designed AlN/Ag@Zn anode delivers an enhanced stability with a long lifespan of more than 2600 h at 1 mA cm-2 and 1 mAh cm-2. Moreover, the AlN/Ag@Zn||Mn1.4V10O24·nH2O full batteries can be operated for over 8000 cycles under 5 A g-1. Our work not only suggests a promising Zn anode protective coating but also provides a general strategy for the rational design of surface protective layers for metal anodes.

Solvent-Type Passivation Strategy Controls Solid-State Self-Quenching-Resistant Behavior in Sulfur Dots.

Treatment of sulfur dots with polyethylene glycol (PEG) has been an efficient way to achieve a high luminescence quantum yield, and such a PEG-related quantum dot (QD)-synthesis strategy has been well documented. However, the polymeric insulating capping layer acting as the "thick shell" will significantly slow down the electron-transfer efficiency and severely hamper its practical application in an optoelectric field. Especially, the employment of synthetic polymers with long alkyl chains or large molecular weights may lead to structural complexity or even unexpected changes of physical characteristics for QDs. Therefore, in sulfur dot preparation, it is a breakthrough to use short-chain molecular species to replace PEG for better control and reproducibility. In this article, a solvent-type passivation (STP) strategy has been reported, and no PEG or any other capping agent is required. The main role of the solvent, ethanol, is to directly react with NaOH, and the generated sodium ethoxide passivates the surface defects. The afforded STP-enhanced emission sulfur dots (STPEE-SDs) possess not only the self-quenching-resistant feature in the solid state but also the extension of fluorescence band toward the wavelength as long as 645 nm. The realization of sulfur dot emission in the deep-red region with a decent yield (8.7%) has never been reported. Moreover, a super large Stokes shift (300 nm, λex = 345 nm, λem = 645 nm) and a much longer decay lifetime (109 µs) have been found, and such values can facilitate to suppress the negative influence from background signals. Density functional theory demonstrates that the surface passivation via sodium ethoxide is dynamically favorable, and the spectroscopic insights into emission behavior could be derived from the passivation effect of the sulfur vacancy as well as the charge-transfer process dominated by the highly electronegative ethoxide layer.

High-Energy and Long-Lived Zn-MnO2 Battery Enabled by a Hydrophobic-Ion-Conducting Membrane.

Alkaline Zn-MnO2 batteries feature high security, low cost, and environmental friendliness while suffering from severe electrochemical irreversibility for both the Zn anode and MnO2 cathode. Although neutral electrolytes are supposed to improve the reversibility of the Zn anode, the MnO2 cathode indeed experiences a capacity degradation caused by the Jahn-Teller effect of the Mn3+ ion, thus shortening the lifespan of the neutral Zn-MnO2 batteries. Theoretically, the MnO2 cathode undergoes a highly reversible two-electron redox reaction of the MnO2/Mn2+ couple in strongly acidic electrolytes. However, acidic electrolytes would inevitably accelerate the corrosion of the Zn anode, making long-lived acidic Zn-MnO2 batteries impossible. Herein, to overcome the challenges faced by Zn-MnO2 batteries, we propose a hybrid Zn-MnO2 battery (HZMB) by coupling the neutral Zn anode with the acidic MnO2 cathode, wherein the neutral anode and acidic cathode are separated by a proton-shuttle-shielding and hydrophobic-ion-conducting membrane. Benefiting from the optimized reaction conditions for both the MnO2 cathode and Zn anode as well as the well-designed membrane, the HZMB exhibits a high working voltage of 2.05 V and a long lifespan of 2275 h (2000 cycles), breaking through the limitations of Zn-MnO2 batteries in terms of voltage and cycle life.

Improved Hamiltonians for Quantum Simulations of Gauge Theories.

Quantum simulations of lattice gauge theories for the foreseeable future will be hampered by limited resources. The historical success of improved lattice actions in classical simulations strongly suggests that Hamiltonians with improved discretization errors will reduce quantum resources, i.e., require ≳2^{d} fewer qubits in quantum simulations for lattices with d-spatial dimensions. In this work, we consider O(a^{2})-improved Hamiltonians for pure gauge theories and design the corresponding quantum circuits for its real-time evolution in terms of primitive gates. An explicit demonstration for Z_{2} gauge theory is presented including exploratory tests using the ibm_perth device.

Preparation of Dye Molecule-Intercalated MoO3 Organic/Inorganic Superlattice Nanoparticles for Fluorescence Imaging-Guided Catalytic Therapy.

Intercalation of organic molecules into the van der Waals gaps of layered materials allows for the preparation of organic/inorganic superlattices for varying promising applications. Herein, the preparation of a series of dye molecule/MoO3 organic/inorganic superlattice nanoparticles by aqueous intercalation of several dye molecules into layered MoO3 for fluorescence imaging-guided catalytic therapy is reported. The long MoO3 nanobelts are treated by ball milling and subsequent aqueous intercalation followed by a cation ion exchange to obtain the dye molecule-intercalated MoO3 organic/inorganic superlattices. Importantly, because of the activation induced by organic intercalation, the Nile blue (NB)-intercalated MoO3-x (NB-MoO3-x ) nanoparticles show excellent catalytic activity for the generation of reactive oxygen species, that is, hydroxyl radical (·OH) and superoxide anion (·O2- ), through catalyzing H2 O2 and O2 , respectively. Moreover, the intense fluorescence of the intercalated NB molecules endows NB-MoO3-x with the in vivo fluorescence imaging capability. Thus, the polyvinylpyrrolidone-modified NB-MoO3-x nanoparticles can be used for tumor-specific catalytic therapy to realize efficient cancer cell elimination in vitro and fluorescence imaging-guided tumor ablation in vivo.

Co,N-co-doped graphene sheet as a sulfur host for high-performance lithium-sulfur batteries.

To improve the performance of lithium-sulfur (Li-S) batteries, herein, based on the idea of designing a material that can adsorb polysulfides and improve the reaction kinetics, a Co,N-co-doped graphene composite (Co-N-G) was prepared. According to the characterization of Co-N-G, there was a homogeneous and dispersed distribution of N and Co active sites embedded in the Co-N-G sample. The 2D sheet-like microstructure and Co, N with a strong binding energy provided significant physical and chemical adsorption functions, which are conducive to the bonding S and suppression of LiPSs. Moreover, the dispersed Co and N as catalysts promoted the reaction kinetics in Li-S batteries via the reutilization of LiPSs and reduced the electrochemical resistance. Thus, the discharge specific capacity in the first cycle for the Co-N-G/S battery reached 1255.7 mA h g-1 at 0.2C. After 100 cycles, it could still reach 803.0 mA h g-1, with a retention rate of about 64%. This phenomenon proves that this type of Co-N-G composite with Co and N catalysts plays an effective role in improving the performance of batteries and can be further studied in Li-S batteries.

Electrostatic Shielding Regulation of Magnetron Sputtered Al-Based Alloy Protective Coatings Enables Highly Reversible Zinc Anodes.

The uncontrolled zinc dendrite growth during plating leads to quick battery failure, which hinders the widespread applications of aqueous zinc-ion batteries. The growth of Zn dendrites is often promoted by the "tip effect". In this work, we propose a generate strategy to eliminate the "tip effect" by utilizing the electrostatic shielding effect, which is achieved by coating Zn anodes with magnetron sputtered Al-based alloy protective layers. The Al can form a surface insulating Al2O3 layer and by manipulating the Al content of Zn-Al alloy films, we are able to control the strength of the electrostatic shield, therefore realizing a long lifespan of Zn anodes up to 3000 h at a practical operating condition of 1.0 mA cm-2 and 1.0 mAh cm-2. In addition, the concept can be extended to other Al-based systems such as Ti-Al alloy and achieve enhanced stability of Zn anodes, demonstrating the generality and efficacy of our strategy.

Realization of an Optical Thermometer via Structural Confinement and Energy Transfer.

The influence of temperature on a variety of physiological or chemical processes has generated considerable interest, and recently noninvasive lanthanide-incorporated optical thermometers have been considered as promising candidates for monitoring its changes at different scales. Herein, a novel Bi3+-activated Sr3-xGdxGaO4+xF1-x phosphor with tunable color has been constructed by a cooperative cation-anion substitution strategy with to the replacement of [Sr2+-F-] by [Gd3+-O2-]. When x = 0, the sample Sr3GaO4F/Bi3+ possesses a peak wavelength at 438 nm, and this value will shift to 470 nm if x is equal to 1 (Sr2GdGaO5/Bi3+). In addition, photoluminescence tuning from blue to red has been realized successfully by an efficient Bi3+ → Eu3+ energy migration model in Sr2.6Gd0.4GaO4.4F0.6 samples. The specific Bi3+ → Eu3+ energy transfer has been explained by dipole-dipole interactions derived from a model of the Dexter pathway. Intriguingly, the two dopants (a blue signal from Bi3+ and a red signal from Eu3+) possess different thermal responses to increasing temperature. Accordingly, the intensity ratio values are sensitive to the temperature changes. The energy level cross relaxation causes the quenching effect of Bi3+, and the multi-phonon de-excitation mode leads to the thermal quenching of Eu3+. At room temperature (298 K), the determined maximum relative sensitivity (Sr) is 1.27% K-1. Moreover, the absolute sensitivity (Sa) is 0.067 K-1 since the temperature is elevated to 523 K. The collected results are superior to most of the reported optical thermometry materials.

Extension of Spectral Shift Controls from Equivalent Substitution to an Energy Migration Model Based on Eu2+/Tb3+-Activated Ba4-xSrxGd3-xLuxNa3(PO4)6F2 Phosphors.

Single-phase phosphors with tunable emission colors are crucial to develop high-performance white light-emitting diodes since they are valuable to improve the energy efficiency, color rendering index, and correlated color temperature. Most of the studies have been conducted to control the spectral shifts via a polyhedral distortion or chemical unit cosubstitution strategy. The combination of host optimization and dopant activator design in a single-phase phosphor system is very rare. Herein, a partial substitution strategy of [Ba2+-Gd3+] by [Sr2+-Lu3+] has been employed in Ba4-xSrxGd3-x-yLuxNa3(PO4)6F2/5% Eu2+ (x = 0-0.40) phosphors. Also, the energy migration from Eu2+ to Tb3+ ions has been investigated in as-prepared samples. Consequently, the emitted signal is observed to shift from 470 to 575 nm derived from equivalent substitutions, which is attributed to specific performance by the emission profile of Eu2+, and such results are closely related to splitting of the crystal field and energy transfer among various luminescent centers. Moreover, the tunable yellowish-green emitting material has been assembled by incorporating ion pairs (Eu2+ → Tb3+) into the Ba3.85Sr0.15Gd2.85Lu0.15Na3(PO4)6F2, and their relative ratios are varied. The corresponding Eu2+ → Tb3+ energy migration process is assigned to be the dipole-quadrupole interaction by the Inokuti-Hirayama model. This work provides rational guidance for the design and discovery of new products with tunable emission colors, originating from the cosubstitution strategy and energy conversion model.

Multiple Roles of Unconventional Heteroatom Dopants in Chalcogenide Thermoelectrics: The Influence of Nb on Transport and Defects in Bi2Te3.

Improvements in the thermoelectric performance of n-type Bi2Te3 materials to more closely match their p-type counterparts are critical to promote the continued development of bismuth telluride thermoelectric devices. Here the unconventional heteroatom dopant, niobium, has been employed as a donor in Bi2Te3. Nb substitutes for Bi in the rhombohedral Bi2Te3 structure and exhibits multiple roles in its modulation of electrical transport and defect-induced phonon scattering. The carrier concentration is significantly increased as electrons are afforded by aliovalent doping and formation of vacancies on the Te sites. In addition, incorporation of Nb in the pseudoternary Bi2-xNbxTe3-δ system increases the effective mass, m*, which is consistent with cases of "conventional" elemental doping in Bi2Te3. Lastly, inclusion of Nb induces both point and extended defects (tellurium vacancies and dislocations, respectively), enhancing phonon scattering and reducing the thermal conductivity. As a result, an optimum zT of 0.94 was achieved in n-type Bi0.92Nb0.08Te3 at 505 K, which is dramatically higher than an equivalent undoped Bi2Te3 sample. This study suggests not only that is Nb an exciting and novel electron dopant for the Bi2Te3 system but also that unconventional dopants might be utilized with similar effects in other chalcogenide thermoelectrics.

Stepwise Assembly Protocols for the Rational Design of Lanthanide Functionalized Carbon Dots-Hydrogel and its Sensing Evaluation.

Inorganic-organic optical probe based on lanthanide emission will provide a new way for specific applications. In this work, sarcosine and urea are selected as raw materials to synthesize carbon dots with cyan-emissive color. In the next step, indicator components (Ethylene Diamine Tetraacetic Acid and lanthanide ions) are incorporated onto carbon quantum dots (CQDs) and the flexible alginate hydrogel is employed as the host to accommodate the emissive species. The soft material can exhibit typical red and green emissions. Its luminescence is responsive to calcium ions and the detection limit has been calculated to be 0.84 µM and 0.92 µM respectively. Such optical device can be employed as a portable probe in a variety of scientific fields due to its convenience and flexibility.

Insights into 2-Indolylmethanol-Involved Cycloadditions: Origins of Regioselectivity and Enantioselectivity.

To gain insights into 2-indolylmethanol-involved reactions and to understand the origins of regioselectivity and enantioselectivity, theoretical investigations on the reaction mechanisms of three representative cycloadditions of 2-indolylmethanols have been carried out. In Ir-catalyzed regioselective (3 + 3) cycloaddition, it was found that the great difference between the energy barriers of the first initiating steps of the two pathways played a key role in determining the observed high regioselectivity and the C3-nucleophilicity of 2-indolylmethanol in this reaction. In chiral phosphoric acid (CPA)-catalyzed regioselective and enantioselective (3 + 3) and (3 + 4) cycloadditions, it was discovered that the great difference between the energy barriers of the transition states corresponding to the (R)- and (S)-configurations led to the observed high enantioselectivity of the products. In the presence of CPA, the C3-nucleophilicity of 2-indolylmethanol increased, resulting in exclusive regioselectivity. It was discovered that the electronic nature is not a decisive factor for the observed C3-regioselectivity in the delocalized cation of 2-indolylmethanol, and the steric factor should play a crucial role in the observed C3-regioselectivity. This study offers insights into the mechanisms of 2-indolylmethanol-involved reactions, which will give an in-depth understanding of the chemistry of 2-indolylmethanols and advance the development of this research field.

Rapid conversion from common precursors to carbon dots in large scale: Spectral controls, optical sensing, cellular imaging and LEDs application.

The commercial production of carbon dots will be concerned with the simplicity and energy consumption. Herein, maleic acid and m-phenylenediamine form elegantly simple sources for carbon dots. The two precursors are dissolved in formamid (abbreviated as FA) or N,N-dimethylformamide (abbreviated as DMF) and the dehydration-condensation processes have been performed at 30 min or 120 min under room temperature. No external energy/irradiations, reactants or high temperature will be required and the afforded carbon dots (abbreviated as CDs) are collected by extraction, centrifugation, dialysis and column chromatography. It has been found for the first time the choice of organic solvents has been correlated with emission color. The blue-emitting CDs (abbreviated as B-CDs) and green-emitting CDs (abbreviated as G-CDs) are yielded in FA and DMF respectively. Facts support that the increase of -CONH- units causes red-shift in emissions. The optical sensing of tetracycline has been explored and the detection limit of blue-emitting CDs is as low as 25 nM. Live cells exposed to B-CDs and G-CDs (0.5 mg/ml) show no apparent changes via both Cell Counting Kit-8 and Annexin V/7-AAD analysis. The blue and green fluorescent signals can be easily tracked in cells. It has been demonstrated that the two carbon dots can be fabricated as multiple-color light-emitting diodes (abbreviated as LEDs).