The Role of Transition Metal Versus Coordination Mode in Single-Atom Catalyst for Electrocatalytic Sulfur Reduction Reaction.

Electrocatalytic sulfur reduction reaction (SRR) is emerging as an effective strategy to combat the polysulfide shuttling effect, which remains a critical factor impeding the practical application of the Li-S battery. Single-atom catalyst (SAC), one of the most studied catalytic materials, has shown considerable potential in addressing the polysulfide shuttling effect in a Li-S battery. However, the role played by transition metal vs coordination mode in electrocatalytic SRR is trial-and-error, and the general understanding that guides the synthesis of the specific SAC with desired property remains elusive. Herein, we use first-principles calculations and machine learning to screen a comprehensive data set of graphene-based SACs with different transition metals, heteroatom doping, and coordination modes. The results reveal that the type of transition metal plays the decisive role in SAC for electrocatalytic SRR, rather than the coordination mode. Specifically, the 3d transition metals exhibit admirable electrocatalytic SRR activity for all of the coordination modes. Compared with the reported N3C1 and N4 coordinated graphene-based SACs covering 3d, 4d, and 5d transition metals, the proposed para-MnO2C2 and para-FeN2C2 possess significant advantages on the electrocatalytic SRR, including a considerably low overpotential down to 1 mV and reduced Li2S decomposition energy barrier, both suggesting an accelerated conversion process among the polysulfides. This study may clarify some understanding of the role played by transition metal vs coordination mode for SAC materials with specific structure and desired catalytic properties toward electrocatalytic SRR and beyond.

Unraveling Mechanism for Microstructure Engineering toward High-Capacity Nickel-Rich Cathode Materials.

Microstructural engineering on nickel-rich layered oxide (NRLO) cathode materials is considered a promising approach to increase both the capacity and lifespan of lithium-ion batteries by introducing high valence-state elements. However, rational regulation on NRLO microstructures based on a deep understanding of its capacity enhancement mechanism remains challenging. Herein for the first time, it is demonstrated that an increase of 14 mAh g-1 in reversible capacity at the first cycle can be achieved via tailoring the micro and nano structure of NRLO through introducing tungsten. Aberration-corrected scanning transmission electron microscopy (STEM) characterization reveals that the formation of a modified microstructure featured as coherent spinel twin boundaries. Theoretical modeling and electrochemical investigations further demonstrate that the capacity increase mechanism is related to such coherent spinel twin boundaries, which can lower the Li+ diffusion barrier and thus allow more Li+ to participate in deeper phase transitions. Meanwhile, the surface and grain boundaries of NRLOs are found to be modified by generating a dense and uniform LiWxOy phase, which further extends its cycle life by reducing side reactions with electrolytes. This work enables a comprehensive understanding of the capacity-increased mechanism and endows the remarkable potential of microstructural engineering for capacity- and lifespan-increased NRLOs.

Cardiovascular admission risk attributable to hot apparent temperature: a study in a rural area of northwest China.

Cardiovascular disease (CVD) is the leading cause of mortality worldwide, posing a significant threat to public health. Research on the relationship between CVD and temperature has primarily focused on developed urban settings, with limited studies conducted in rural regions with lower levels of development. Additionally, compared to relative risks, attributable risks can provide more information when assessing the risk of CVD hospitalizations associated with exposure to apparent temperature (AT). Apparent temperature is a composite temperature index that takes into account both meteorological factors and temperature, providing an objective reflection of human thermal sensation. Therefore, this study investigates the impact of AT on CVD hospitalization and quantifies the burden of CVD admission in the rural areas of China. We employed the distributed lag non-linear model (DLNM) to estimate the relationship between AT and the relative risk (RR) of CVD hospitalization. Finally, we used attributable risk methods to quantify this relationship further.

Kirkendall effect-induced uniform stress distribution stabilizes nickel-rich layered oxide cathodes.

Nickel-rich layered oxide cathodes promise ultrahigh energy density but is plagued by the mechanical failure of the secondary particle upon (de)lithiation. Existing approaches for alleviating the structural degradation could retard pulverization, yet fail to tune the stress distribution and root out the formation of cracks. Herein, we report a unique strategy to uniformize the stress distribution in secondary particle via Kirkendall effect to stabilize the core region during electrochemical cycling. Exotic metal/metalloid oxides (such as Al2O3 or SiO2) is introduced as the heterogeneous nucleation seeds for the preferential growth of the precursor. The calcination treatment afterwards generates a dopant-rich interior structure with central Kirkendall void, due to the different diffusivity between the exotic element and nickel atom. The resulting cathode material exhibits superior structural and electrochemical reversibility, thus contributing to a high specific energy density (based on cathode) of 660 Wh kg-1 after 500 cycles with a retention rate of 86%. This study suggests that uniformizing stress distribution represents a promising pathway to tackle the structural instability facing nickel-rich layered oxide cathodes.

Effects of apparent temperature on cardiovascular disease admissions in rural areas of Linxia Hui Autonomous Prefecture.

Cardiovascular disease (CVD) is a major threat to public health worldwide. The relationship between CVD and temperature has been widely reported in developed countries and regions. However, there are few studies of severe CVD in poor rural areas of developing countries. Therefore, this study aimed to explore the relationship between CVD and apparent temperature (AT) in a rural area of Linxia Hui Autonomous Prefecture, China. Daily CVD admission data and meteorological data were collected from Linxia between 2014 and 2015. The media of AT was used as the reference temperature to estimate the cumulative relative risk (RR) of CVD admission. The distributed lag non-linear models were used to examine the association between AT and cumulative RR of CVD admission at lag 0-21 days. In Linxia, high AT (20 °C) had a persistent adverse effect on cumulative RR of CVD admissions, and the RR increased with increasing lag days. Cold (- 10 °C) had a protective effect on the first and later lag days (lag 0-14 and lag 0-21). Adults (aged < 65 years) and females were more susceptible to the effects of heat than males and the elderly (aged ≥ 65 years). In Linxia, China, extremely high AT is an important risk factor for CVD hospitalizations in suburban and rural populations.

Unique Tridentate Coordination Tailored Solvation Sheath Toward Highly Stable Lithium Metal Batteries.

Electrolyte optimization by solvent molecule design is recognized as an effective approach for stabilizing lithium (Li) metal batteries. However, the coordination pattern of Li ions (Li+ ) with solvent molecules is sparsely considered. Here, an electrolyte design strategy is reported based on bi/tridentate chelation of Li+ and solvent to tune the solvation structure. As a proof of concept, a novel solvent with multi-oxygen coordination sites is demonstrated to facilitate the formation of an anion-aggregated solvation shell, enhancing the interfacial stability and de-solvation kinetics. As a result, the as-developed electrolyte exhibits ultra-stable cycling over 1400 h in symmetric cells with 50 µm-thin Li foils. When paired with high-loading LiFePO4 , full cells maintain 92% capacity over 500 cycles and deliver improved electrochemical performances over a wide temperature range from -10 to 60 °C. Furthermore, the concept is validated in a pouch cell (570 mAh), achieving a capacity retention of 99.5% after 100 cycles. This brand-new insight on electrolyte engineering provides guidelines for practical high-performance Li metal batteries.

Electrostatic Interaction Tailored Anion-Rich Solvation Sheath Stabilizing High-Voltage Lithium Metal Batteries.

Through tailoring interfacial chemistry, electrolyte engineering is a facile yet effective strategy for high-performance lithium (Li) metal batteries, where the solvation structure is critical for interfacial chemistry. Herein, the effect of electrostatic interaction on regulating an anion-rich solvation is firstly proposed. The moderate electrostatic interaction between anion and solvent promotes anion to enter the solvation sheath, inducing stable solid electrolyte interphase with fast Li+ transport kinetics on the anode. This as-designed electrolyte exhibits excellent compatibility with Li metal anode (a Li deposition/stripping Coulombic efficiency of 99.3%) and high-voltage LiCoO2 cathode. Consequently, the 50 µm-thin Li||high-loading LiCoO2 cells achieve significantly improved cycling performance under stringent conditions of high voltage over 4.5 V, lean electrolyte, and wide temperature range (- 20 to 60 °C). This work inspires a groundbreaking strategy to manipulate the solvation structure through regulating the interactions of solvent and anion for high-performance Li metal batteries.

Rational Electrolyte Design toward Cyclability Remedy for Room-Temperature Sodium-Sulfur Batteries.

Rechargeable room-temperature sodium-sulfur (RT Na-S) batteries are a promising energy storage technology, owing to the merits of high energy density and low cost. However, their electrochemical performance has been severely hindered by the poor compatibility between the existing electrolytes and the electrodes. Here, we demonstrate that an all-fluorinated electrolyte, containing 2,2,2-trifluoro-N,N-dimethylacetamide (FDMA) solvent, 1,1,2,2-tetrafluoroethyl methyl ether (MTFE) anti-solvent and fluoroethylene carbonate (FEC) additive, can greatly enhance the reversibility and cyclability of RT Na-S batteries. A NaF- and Na3 N-rich cathode electrolyte interphase derived from FDMA and FEC enables a "quasi-solid-phase" Na-S conversion, eliminating the shuttle of polysulfides. The MTFE not only reduces polysulfide dissolution, but also further stabilizes the Na anode via a tailored solvation structure. The as-developed RT Na-S batteries deliver a high capacity, long lifespan, and enhanced safety.

Complexation with aromatic carboxylic acids expands the solid-state landscape of berberine.

Two novel salt cocrystals of berberine chloride (BCl) with 4-aminobenzoic acid (BCl-4ABA) and 4-hydroxybenzoic acid (BCl-4HBA) and one new berberine salt with 2,6-dihydroxybenzoic acid (B)+(26DHBA)- were prepared and characterized. The chloride anions form NH···Cl- hydrogen bonds in BCl-4ABA and OH···Cl- hydrogen bonds in BCl-4HBA. In (B)+(26DHBA)-, the ionic interactions between 26DHBA- and quaternary ammonium cation of berberine contribute to a stronger crystal lattice and a higher melting point. All three new crystal forms exhibit a lower hygroscopicity at 25 °C than BCl, which is the crystal form used in the commercial tablets. Compared to BCl, the dissolution rates of BCl-4ABA and BCl-4HBA in water are higher but that of (B)+(26DHBA)- is lower. Among the three crystal forms, the form with a higher melting point also exhibits a lower dissolution rate, which is explained by the stronger intermolecular interactions in these crystals.

Crystal structure, dissolution and hygroscopicity of a novel cocrystal hydrate of berberine hydrochloride with L(+)-lactic acid.

Berberine hydrochloride (BCl) is commercially used to treat diarrhea, diabetes, hyperlipidemia, and cancer. However, BCl suffers from solid state instability, low aqueous solubility, low dissolution rate, and poor bioavailability, which limit its potential application in clinical medicine. In this work, we report a novel cocrystal hydrate of BCl with L(+)-lactic acid (BCl-LA-H2O), designed to improve its physicochemical properties, thus promoting its application in the pharmaceutical industry. As a result, the cocrystal strategy improved the solubility, dissolution, melting point, and hygroscopicity of BCl, which indicated that the BCl-LA-H2O can be used as a better solid form.