Design principles of heterointerfacial redox chemistry for highly reversible lithium metal anode.

High electrochemical reversibility is required for the application of high-energy-density lithium (Li) metal batteries; however, inactive Li formation and SEI (solid electrolyte interface)-instability-induced electrolyte consumption cause low Coulombic efficiency (CE). The prior interfacial chemical designs in terms of alloying kinetics have been used to enhance the CE of Li metal anode; however, the role of its redox chemistry at heterointerfaces remains a mystery. Herein, the relationship between heterointerfacial redox chemistry and electrochemical transformation reversibility is investigated. It is demonstrated that the lower redox potential at heterointerface contributes to higher CE, and this enhancement in CE is primarily due to the regulation of redox chemistry to Li deposition behavior rather than the formation of SEI films. Low oxidation potential facilitates the formation of the surface with the highly electrochemical binding feature after Li stripping, and low reduction potential can maintain binding ability well during subsequent Li plating, both of which homogenize Li deposition and thus optimize CE. In particular, Mg hetero-metal with ultra-low redox potential enables Li metal anode with significantly improved CE (99.6%) and stable cycle life for 700 cycles at 3.0 mA cm-2. This work provides insight into the heterointerfacial design principle of next-generation negative electrodes for highly reversible metal batteries.

Enhancement of Overall Kinetics by Se-Br Chemistry in Rechargeable Li-S Batteries.

The sluggish kinetics of lithium-sulfur (Li-S) batteries severely impedes the application in extreme conditions. Bridging the sulfur cathode and lithium anode, the electrolyte plays a crucial role in regulating kinetic behaviors of Li-S batteries. Herein, we report a multifunctional electrolyte additive of phenyl selenium bromide (PhSeBr) to simultaneously exert positive influences on both electrodes and the electrolyte. For the cathode, an ideal conversion routine with lower energy barrier can be attained by the redox mediator and homogeneous catalyst derived from PhSeBr, thus improving the reaction kinetics and utilization of sulfur. Meanwhile, the presence of Se-Br bond helps to reconstruct a loose solvation sheath of lithium ions and a robust bilayer SEI with excellent ionic conductivity, which contributes to reducing the de-solvation energy and simultaneously enhancing the interfacial kinetics. The Li-S battery with PhSeBr displays superior long cycling stability with a reversible capacity of 1164.7 mAh g-1 after 300 cycles at 0.5 C rate. And the pouch cell exhibits a maximum capacity of 845.3 mAh and a capacity retention of 94.8 % after 50 cycles. Excellent electrochemical properties are also obtained in extreme conditions of high sulfur loadings and low temperature of -20 °C. This work demonstrates the versatility and practicability of the special additive, striking out an efficient but simple method to design advanced Li-S batteries.

Tailoring Li Deposition by Regulating Structural Connectivity of Electrochemical Li Reservoir in Li-metal Batteries.

Irregular Li deposition is the major reason for poor reversibility and cycle instability in Li metal batteries, even leading to safety hazards, the causes of which have been extensively explored. The structural disconnection induced by completely dissolving Li in the traditional testing protocol is a key factor accounting for irregular Li growth during the subsequent deposition process. Herein, the critical role played by the structural connectivity of electrochemical Li reservoir in subsequent Li deposition behaviors is elucidated and a morphology-performance correlation is established. The structural connection and resultant well-distributed morphology of the in situ electrochemical Li reservoir ensure efficient electron transfer and Li+ diffusion pathway, finally leading to homogenized Li nucleation and growth. Tailoring the geometry of Li reservoir can improve the coulombic efficiency and cyclability of anode-free Li metal batteries by optimizing Li deposition behavior.

Artificial Post-Cycled Structure Modulation Towards Highly Stable Li-Rich Layered Cathode.

High-capacity Li-rich layered oxides (LLOs) suffer from severe structure degradation due to the utilization of hybrid anion- and cation-redox activity. The native post-cycled structure, composed of progressively densified defective spinel layer (DSL) and intrinsic cations mixing, is deemed as the hindrance of the rapid and reversible de/intercalation of Li+ . Herein, the artificial post-cycled structure consisting of artificial DSL and inner cations mixing is in situ constructed, which would act as a shield against the irreversible oxygen emission and undesirable transition metal migration by suppressing anion redox activity and modulating cation mixing. Eventually, the modified DSL-2% Li-rich cathode demonstrates remarkable electrochemical properties with a high discharge capacity of 187 mAh g-1 after 500 cycles at 2 C, and improved voltage stability. Even under harsh operating conditions of 50 °C, DSL-2% can provide a high discharge capacity of 168 mAh g-1 after 250 cycles at 2 C, which is much higher than that of pristine LLO (92 mAh g-1 ). Furthermore, the artificial post-cycled structure provides a novel perspective on the role of native post-cycled structure in sustaining the lattice structure of the lithium-depleted region and also provides an insightful universal design principle for highly stable intercalated materials with anionic redox activity.

Ideal shape of Fresnel lens for visible solar light concentration.

This paper presents theoretical research based on the optimal transmittance condition of a prism to find an ideal shape for Fresnel lenses to concentrate visible solar light. First, the ideal-shape equation was derived out through a simplified method that uses one refraction on the midline of a prism to replace the two refractions, respectively, on its upper and lower interfaces. It has been assumed that the Fresnel lens is thin enough to consider each prism as a point, then all the simplified points form a curve. The differential equation of this curve was built up, which has been solved and expressed by a parametric formula. The parametric formula is defined as the ideal-shape equation of Fresnel lens. Second, the optimal combination of the total refracted angle θ and refractive index n has been analyzed to determine the maximal transmittance. The quantitative analysis has indicated that only one group of (θ, n) can achieve the optimal Fresnel lens' transmittance. Finally, the maximal geometrical concentration ratio Cg of ideal Fresnel lens has been discussed. When material is defined, there is a unique θ that makes the geometric concentration maximal for visible solar light. Generally, materials with low refractive index can be used to design a Fresnel lens with larger Cg.

Cu@Ni core-shell nanoparticles prepared via an injection approach with enhanced oxidation resistance for the fabrication of conductive films.

Building core-shell structures is a valuable method of enhancing the oxidation-resistance performance of Cu nanoparticles for practical applications in the field of printed circuit boards. In this study, Cu@Ni core-shell nanoparticles are synthesized via an injection solution approach utilizing Cu seeds produced during the reactions to induce the epitaxial growth of Ni shells. The thickness of the Ni shell can be controlled by varying the Cu:Ni molar ratios in the injected precursor solution, whereas changing the injection rate of the Cu precursor solution affects the size of the Cu seeds and thus controls the eventual size of the core-shell nanoparticles. Thermogravimetric analysis reveals a superior thermal stability against oxidation for Cu@Ni core-shell nanoparticles, as compared with Cu nanoparticles. The oxidation resistance of Cu@Ni conductive films increases with an increase in the Ni:Cu ratio, while the conductivity increases with a decrease in the Ni:Cu ratio. A relatively low resistivity of 27.4 µΩ cm is achieved for Cu@Ni conductive films. The results demonstrate that coating Cu nanoparticles with Ni shells via epitaxial growth can form closed shells with smooth surfaces which are valuable for Cu nanoparticles in applications where oxidation resistance is a requirement .

Lithium Deficiencies Engineering in Li-Rich Layered Oxide Li1.098Mn0.533Ni0.113Co0.138O2 for High-Stability Cathode.

Li-rich layered oxides have been in focus because of their high specific capacity. However, they usually suffer from poor kinetics, severe voltage decay, and capacity fading. Herein, a long-neglected Li-deficient method is demonstrated to address these problems by simply reducing the lithium content. Appropriate lithium vacancies can improve dynamics features and induce in situ surface spinel coating and nickel doping in the bulk. Therefore, the elaborately designed Li1.098Mn0.533Ni0.113Co0.138O2 cathode possesses improved initial Coulombic efficiency, excellent rate capability, largely suppressed voltage decay, and outstanding long-term cycling stability. Specifically, it shows a superior capacity retention of 93.1% after 500 cycles at 1 C (250 mA g-1) with respect to the initial discharge capacity (193.9 mA h g-1), and the average voltage still exceeds 3.1 V. In addition, the discharge capacity at 10 C can be as high as 132.9 mA h g-1. More importantly, a Li-deficient cathode can also serve as a prototype for further performance enhancement, as there are plenty of vacancies.

3D Graphene Encapsulated Hollow CoSnO3 Nanoboxes as a High Initial Coulombic Efficiency and Lithium Storage Capacity Anode.

3D Graphene sheets encapsulated amorphous hollow CoSnO3 nanoboxes (H-CoSnO3 @reduced graphene oxide [RGO]) are successfully fabricated by first preparing 3D graphene oxides encapsulated solid CoSn(OH)6 nanocubes, followed by an alkaline etching process and subsequent heating treatment in Ar. The hollow CoSnO3 nanoboxes with average particle size of 230 nm are uniformly and tightly encapsulated by RGO sheets. As an anode material for Li-ion batteries, H-CoSnO3 @RGO displays high initial Coulombic efficiency of 87.1% and large reversible capacity of 1919 mA h g-1 after 500 cycles at the current density of 500 mA g-1 . Moreover, excellent rate capability (1250, 1188, 1141, 1115, 1086, 952, 736, and 528 mA h g-1 at 100, 200, 300, 400, 500, 1000, 2000, and 5000 mA g-1 , respectively) is acquired. The reasons for excellent lithium storage properties of H-CoSnO3 @RGO are discussed in detail.

Hyperspectral Imaging for Evaluating Impact Damage to Mango According to Changes in Quality Attributes.

Evaluation of impact damage to mango (Mangifera indica Linn) as a result of dropping from three different heights, namely, 0.5, 1.0 and 1.5 m, was conducted by hyperspectral imaging (HSI). Reflectance spectra in the 900⁻1700 nm region were used to develop prediction models for pulp firmness (PF), total soluble solids (TSS), titratable acidity (TA) and chroma (∆b*) by a partial least squares (PLS) regression algorithm. The results showed that the changes in the mangoes' quality attributes, which were also reflected in the spectra, had a strong relationship with dropping height. The best predictive performance measured by coefficient of determination (R²) and root mean square errors of prediction (RMSEP) values were: 0.84 and 31.6 g for PF, 0.9 and 0.49 oBrix for TSS, 0.65 and 0.1% for TA, 0.94 and 0.96 for chroma, respectively. Classification of the degree of impact damage to mango achieved an accuracy of more than 77.8% according to ripening index (RPI). The results show the potential of HSI to evaluate impact damage to mango by combining with changes in quality attributes.

Thermo-Economic Optimization of an Idealized Solar Tower Power Plant Combined with MED System.

Based on the reversible heat engine model, theoretical analysis is carried out for economic performance of a solar tower power plant (STPP) combined with multi-effect desalination (MED). Taking total revenue of the output power and the fresh water yield per unit investment cost as the economic objective function, the most economical working condition of the system is given by analyzing the influence of the system investment composition, the receiver operating temperature, the concentration ratio, the efficiency of the endoreversible heat engine, and the relative water price on the economic parameters of the system. The variation curves of the economic objective function are given out when the main parameter is changed. The results show that the ratio of water price to electricity price, or relative price index, has a significant impact on system economy. When the water price is relatively low, with the effect numbers of the desalination system increasing, and the economic efficiency of the overall system worsens. Only when the price of fresh water rises to a certain value does it make sense to increase the effect. Additionally, the threshold of the fresh water price to the electricity price ratio is 0.22. Under the conditions of the current price index and the heliostat (or reflector), the cost ratio and the system economy can be maximized by selecting the optimum receiver temperature, the endoreversible heat engine efficiency, and the optimum concentration ratio. Given the receiver surface temperature and the endoreversible heat engine efficiency, increasing the system concentration ratio of the heliostat will be in favor of the system economy.

Association of heat shock protein 90 with the developmental competence of immature oocytes following Cryotop and solid surface vitrification in yaks (Bos grunniens).

The correlation between the 90 kDa heat-shock protein (HSP90) and the developmental competence of yak (Bos grunniens) oocytes following the process of vitrification has not been studied clearly. In the present study, we compare the efficacies of Cryotop (CT) and solid surface vitrification (SSV) methods for the cryopreservation of immature yak oocytes. Yak cumulus oocyte complexes were randomly allocated into three groups: (1) controls, (2) CT vitrification, and (3) SSV vitrification. Oocytes were vitrified and in vitro maturated and fertilized. The percentages of nuclear maturation and in vitro development were evaluated. The vitrified-warmed oocytes were evaluated for mRNA and protein expression levels of HSP90 using quantitative real-time PCR and western blotting at various stages: matured oocytes, 2-8 cells embryos and blastocysts. No difference was found in the percentages of nuclear maturation, cleavage or blastocyst in the two vitrified groups; however, the rates of maturation were significantly lower than those in the control group. Among the three groups, the maturation rates in CT: 51.14±0.86% and SSV: 50.82±1.34% were less than those of the controls: 69.65±1.13%; the cleavage rates in CT: 39.16±1.01% and SSV: 39.08±0.92%, were less than those of the controls: 58.14±0.76%; but the blastocysts rates and total cell number in the blastocysts were similar: CT: 32.20±0.73% and 104.6±3.72; SSV: 32.35±0.81% and 102.4±1.34; and controls: 34.38±1.32% and 103.8±4.13, respectively. The HSP90 expression level in the matured oocytes and 2-8 cell embryos of the control group was significantly higher than that in the two vitrified groups; there was not significant difference in the blastocysts in the three groups. We thus conclude that CT and SSV perform equally in the vitrification of immature yak oocytes during the process of cryopreservation, and their influence on oocytes mainly occured from the maturation to cleavage stages. The HSP90 levels in the blastocysts of the vitrified groups increased is associated with the developmental competence of the embryo.

[Comparison of relevant indicators of coagulation and fibrinolysis in patients with varying severity of community-acquired pneumonia].

OBJECTIVE: To compare the relevant indicators of coagulation and fibrinolysis in patients with varying severity of community-acquired pneumonia (CAP). METHODS: A total of 107 CAP hospitalized patients at Department of Respiratory Medicine, Affiliated Hospital, Chengde Medical College from July 2013 to June 2014 were enrolled as pneumonia group while another 52 healthy outpatients served as control group. The levels of routine blood test, coagulation function, procalcitonin and C-reactive protein (CRP) were measured and compared among different groups. All hospitalized CAP patients were divided into low and high-risk groups according to pneumonia severity index (PSI). And all indicators were measured to examine the differences among different groups. RESULTS: The white blood cell count in pneumonia group was significantly higher than that in control group ((9.3 ± 5.1) vs (7.5 ± 2.9) × 10(9)/L, P < 0.05). The red blood cell count, hemoglobin and platelet count in pneumonia group were significantly lower than those in control group ((4.3 ± 0.6) vs (4.8 ± 0.5) × 10(12)/L, (131.1 ± 18.7) vs (144.9 ± 17.4) g/L, (199.3 ± 69.4) vs (237.9 ± 72.5) × 10(9)/L, all P < 0.05). The D-dimer, fibrinogen degradation products (FDPs), fibrinogen (FIB), activated partial thromboplastin time (APTT) and prothrombin time (PT) in pneumonia group were significantly higher than those in control group ((1.86 ± 1.28) vs (0.48 ± 0.38) mg/L, (6.42 ± 3.27) vs (2.17 ± 1.46) mg/L, (3.87 ± 1.17) vs (3.42 ± 0.96) g/L, (35.64 ± 8.34) vs (31.29 ± 11.19) s, (12.21 ± 1.40) vs (11.36 ± 2.19) s, all P < 0.05) while thromboplastin time (TT) was lower than that in control group ((13.43 ± 3.38) vs (16.16 ± 2.89) s, P < 0.05). The levels of D-dimer, FDPs, procalcitonin, CRP, APTT and PT in high-risk group were significantly higher than those in low-risk group ((2.94 ± 1.14) vs (1.16 ± 0.78) mg/L, (8.85 ± 2.82) vs (4.85 ± 2.49) mg/L, (1.72 ± 1.16) vs (0.40 ± 0.51) µg/L, (104.2 ± 61.9) vs (67.4 ± 59.5) mg/L, (38.80 ± 8.41) vs (33.60 ± 7.69) s, (12.64 ± 1.76) vs (11.94 ± 1.03) s, all P < 0.05) while platelet count and TT were lower than those in low-risk group ((172.8 ± 57.1) vs (216.5 ± 71.6) × 10(9)/L, (12.10 ± 2.66) vs (14.28 ± 3.53) s, all P < 0.05). The abnormal rates of procalcitonin, D-dimer and FDPs in high-risk group were significantly higher than those in low-risk group (100% (42/42) vs 86.2% (56/65), 95.2% (40/42) vs 75.4% (49/65), 95.2% (37/42) vs 44.6% (29/65), all P < 0.05). The plasma levels of D-dimer, FDPs, procalcitonin and CRP were well-correlated with index of pneumonia severity (r = 0.636, 0.608, 0.629, 0.250, all P < 0.05). And the plasma level of platelet was negatively correlated with index of pneumonia severity (r = -0.320, P < 0.01). CONCLUSIONS: The red blood cell, hemoglobin and platelets are lower in patients with pneumonia than those in normal subjects. And the patients with pneumonia have coagulation and fibrinolysis disorders. The plasma levels of D-dimer, FDPs, procalcitonin, CRP and platelets are well-correlated with severity of CAP.

[Peripheral blood cell factors of Graves ophthalmopathy and effect of intervention with tripterygium glycosides].

To explore the effect of tripterygium glycosides on the level of peripheral blood cell factors of Graves ophthalmopathy (GO). In the study, 64 patients of GO in moderate-severe acute stage were selected, and randomly divided into the treatment group (32 cases) and the control group (32 cases). Both of the two groups were provided with basic treatment. The control group was added with prednisone(0. 75 mg kg-1 d-1 ), which gradually reduced (by 5-10 mg week-1 )to the minimum dose of 5 mg d-1. The treatment group was treated with 20 mg tripterygium glycosides, three times a day. One therapy course is three months. The levels of peripheral blood cells(TNF-alpha , IL-2, IL-10, IFN-gamma)of the two groups before and after the treatment and the clinical efficacy were observed. The study indicated that, before the treatment, TNF-alpha, IL-2, IFN-gamma in both groups were significantly higher than that in the health group, but with IL-10 notably lower than the healthy group. After the treatment, TNF-a, IL-2, IFN-gamma in the treatment group significantly decreased, but with IL-10 significantly increasing (P <0. 01). After the treatment, the two groups showed significant difference (P <0. 01). The total clinical efficacy in the treatment group was 88. 10% , and that in the control group was 57. 14% (P <0. 01). After the treatment, the two groups showed significant changes in the exophthalmos degree (P < 0. 01). The results showed that the level of peripheral blood cells (TNF-alpha,IL-2, IL-10, IFN-gamma)of GO patients was positively correlated with the severity of ocular disease. The combined therapy of tripterygium glycosides and methimazole show such advantages as low side effect and high clin-

Stat3 Has a Different Role in Axon Growth During Development Than It Does in Axon Regeneration After Injury.

Signal transducer and activator of transcription 3 (STAT3) is essential for neural development and regeneration as a key transcription factor and mitochondrial activator. However, the mechanism of Stat3 in axon development and regeneration has not been fully understood. In this study, using zebrafish posterior lateral line (PLL) axons, we demonstrate that Stat3 plays distinct roles in PLL axon embryonic growth and regeneration. Our experiments indicate that stat3 is required for PLL axon extension. In stat3 mutant zebrafish, the PLL axon ends were stalled at the level of the cloaca, and expression of stat3 rescues the PLL axon growth in a cell-autonomous manner. Jak/Stat signaling inhibition did not affect PLL axon growth indicating Jak/Stat was dispensable for PLL axon growth. In addition, we found that Stat3 was co-localized with mitochondria in PLL axons and important for the mitochondrial membrane potential and ATPase activity. The PLL axon growth defect of stat3 mutants was mimicked and rescued by rotenone and DCHC treatment, respectively, which suggests that Stat3 regulates PLL axon growth through mitochondrial Stat3. By contrast, mutation of stat3 or Jak/Stat signaling inhibition retarded PLL axon regeneration. Meanwhile, we also found Schwann cell migration was also inhibited in stat3 mutants. Taken together, Stat3 is required for embryonic PLL axon growth by regulating the ATP synthesis efficiency of mitochondria, whereas Stat3 stimulates PLL axon regeneration by regulating Schwann cell migration via Jak/Stat signaling. Our findings show a new mechanism of Stat3 in axon growth and regeneration.

Role of miR-584-5p in Lipopolysaccharide-Stimulated Human Bronchial Epithelial Cell Inflammation and Apoptosis.

Acute lung injury (ALI)/acute respiratory distress syndrome is a common clinical syndrome characterized by respiratory failure. MicroRNAs (miRNAs) are closely related to ALI and acute respiratory distress syndrome. TargetScan software analysis showed that miR-584-5p can bind to the 3' noncoding region of TLR4, which is involved in the occurrence and development of ALI, thereby affecting the inflammatory pathway and inflammation development. Thus, we aimed to determine whether miR-584-5p affects ALI. Human bronchial epithelial (16-HBE) cells were transfected with miR-584-5p mimics or inhibitors and then stimulated with lipopolysaccharide (LPS).The cell viability, apoptosis, release of proinflammatory factors, mTOR, and NF-κB pathway protein expression were evaluated respectively. Mimic584 increased, whereas inhibitor584 decreased, LPS-stimulated inflammation. The protein expression of inflammatory factors was significantly increased in 16-HBE cells in the mimic584 + LPS group and decreased in the inhibitor584 + LPS group. Mimic584 activated mTOR and the NF-κB-related proteins P65 and p-p65, whereas inhibitor584 inactivated the proteins in 16-HBE cells. Overexpression of miR-584 significantly promoted apoptosis in LPS-stimulated 16-HBE cells. There were no differences in the proliferation and cell cycle of LPS-stimulated 16-HBE cells regardless of mimic584 or inhibitor584 transfection. Collectively, we demonstrated that inhibitor584 can alleviate ALI-induced expression of inflammatory factors via mTOR signaling and the NF-κB pathway. In conclusion, we found that inhibitor584 transfection could be a potential therapeutic strategy for ALI.

Coordinating ionic and electronic conductivity on 3D porous host enabling deep dense lithium deposition toward high-capacity lithium metal anodes.

Engineering composite lithium (Li) metal within three-dimensional (3D) porous skeleton hosts is a feasible strategy to tackle issues of uncontrollable dendrite growth and enormous volume change on Li metal anodes. Nevertheless, the accumulative Li deposition on the top surface of the 3D skeleton remains a harsh challenge that still requires effort. Herein, we develop a rational design involving an enriched-sparse LiF gradient on a Cu foam via facile magnetron sputtering to coordinate ionic and electronic conductivity. The Li ion-conductive LiF gradient guides deep, dense Li deposition within the Cu foam framework, safely preventing surface Li accumulation. As a result, the Cu foam with optimal LiF sputtering time for 40 min (Cu foam/LiF(40)) renders the best synergy of ionic and electronic conduction. Such composite Li anode in the symmetric cell achieves an ultra-long lifespan up to 1700 h at the current density of 2 mA cm-2 with the capacity of 2 mA h cm-2. This work certifies the decisive significance of coordinating ionic and electronic conductivity for uniform Li deposition on 3D porous hosts and provides a simple and effective avenue to controllably deposit Li in suitable locations for long-term and high-capacity 3D Li metal anodes.

Composition-dependent activity of ZnxCd1-xSe solid solution coupled with Ni2P nanosheets for visible-light-driven photocatalytic H2 generation.

Metal selenide semiconductors have been rarely used for photocatalytic water splitting because of their poor stability and severe photocorrosion properties. Hence, designing stable metal selenides with suitable bandgap energies has considerable practical significance in photocatalytic H2 evolution. In this work, a novel series of ZnxCd1-xSe (x = 0 âˆ¼ 1) with tunable band structure were fabricated through a simple solvothermal method. Impressively, the ZnSe exhibited a maximum H2 production rate of 1056 µmol g-1h-1, which was higher than that of CdSe and ZnxCd1-xSe solid solutions. Such visible-light photoactivity for water reduction to H2 was attained even after 6 cycling photocatalytic experiments. Moreover, the two-dimensional (2D) Ni2P nanosheets act as a high-efficiency cocatalyst integrated with ZnxCd1-xSe semiconductor to boost photocatalytic H2 generation performance. The optimal 8% Ni2P/ZnSe composites displayed excellent cycling stability and superior photocatalytic H2 evolution performance (4336 µmol g-1h-1), which was about 4.1 times that of pure ZnSe under visible light irradiation. Photoelectrochemical (PEC), photoluminescence (PL), and time-resolved photoluminescence (TRPL) measurements reveal that the improved photoactivity Ni2P/ZnSe photocatalysts were ascribed to the effective separation and migration of photoinduced carriers. The present work paves a pathway to explore the fabrication of ZnxCd1-xSe solid solutions and the hybridization of 2D transition metal phosphides nanosheets toward photocatalytic applications.

Composite NiCo2 O4 @CeO2 Microsphere as Cathode Catalyst for High-Performance Lithium-Oxygen Battery.

The large overpotential and poor cycle stability caused by inactive redox reactions are tough challenges for lithium-oxygen batteries (LOBs). Here, a composite microsphere material comprising NiCo2 O4 @CeO2 is synthesized via a hydrothermal approach followed by an annealing processing, which is acted as a high performance electrocatalyst for LOBs. The unique microstructured catalyst can provide enough catalytic surface to facilitate the barrier-free transport of oxygen as well as lithium ions. In addition, the special microsphere and porous nanoneedles structure can effectively accelerate electrolyte penetration and the reversible formation and decomposition process of Li2 O2 , while the introduction of CeO2 can increase oxygen vacancies and optimize the electronic structure of NiCo2 O4 , thereby enhancing the electron transport of the whole electrode. This kind of catalytic cathode material can effectively reduce the overpotential to only 1.07 V with remarkable cycling stability of 400 loops under 500 mA g-1 . Based on the density functional theory calculations, the origin of the enhanced electrochemical performance of NiCo2 O4 @CeO2 is clarified from the perspective of electronic structure and reaction kinetics. This work demonstrates the high efficiency of NiCo2 O4 @CeO2 as an electrocatalyst and confirms the contribution of the current design concept to the development of LOBs cathode materials.

An Ultrahigh-Power Mesocarbon Microbeads|Na+ -Diglyme|Na3 V2 (PO4 )3 Sodium-Ion Battery.

Sodium-ion batteries (SIBs) show practical applications in large-scale energy storage systems. But, their power density is limited by the sluggish Na+ diffusion into the cathode and anode materials. Herein, the authors demonstrate a prototype of ultrahigh power SIB, consisting of the high-rate Na3 V2 (PO4 )3 (NVP) cathode, graphite-type mesocarbon microbeads (MCMB) anode, and Na+ -diglyme electrolyte. It is found that the overpotential of the NVP cathode obeys the Ohmic rule. Thus, the as-synthesized NVP@C@carbon nanotubes (CNTs) cathode with the high conductive CNTs networks displays high electronic conductivity, reducing the overpotential and charge transfer resistances and leading to the remarkable rate capability over 1000C. For the MCMB anode, the initial [Na-diglyme]+ co-intercalation step is pseudocapacitive dominated, and then the expanded graphite's layers ensure the subsequent fast ions diffusion. The rapid (de)intercalation kinetics in between the cathode and anode are well-matched. Thus, the assembled MCMB|1 m NaPF6 in diglyme|NVP@C@CNTs full-cell SIB delivers the energy density of 88 Wh kg-1 at the high power density of ≈10 kW kg-1 . Even at the ultrahigh power density of 23 kW kg-1 , an energy density of 58 Wh kg-1 is obtained. The encouraging results of the full cell will promote the development of high-power SIB for large-scale applications in the future.

Adjustable Mixed Conductive Interphase for Dendrite-Free Lithium Metal Batteries.

Lithium (Li) metal batteries with high energy density are of great promise for next-generation energy storage; however, they suffer from severe Li dendritic growth and an unstable solid electrolyte interphase. In this study, a mixed ionic and electronic conductive (MIEC) interphase layer with an adjustable ratio assembled by ZnO and Zn nanoparticles is developed. During the initial cycle, the in situ formed Li2O with high ionic conductivity and a lithiophilic LiZn alloy with high electronic conductivity enable fast Li+ transportation in the interlayer and charge transfer at the ion/electron conductive junction, respectively. The optimized interface kinetics is achieved by balancing the ion migration and charge transfer in the MIEC Li2O-LiZn interphase. As a result, the symmetric cell with MIEC interphase delivers superior cycling stability of over 1200 h. Also, Li||Zn-ZnO@PP||LFP (LFP = LiFePO4) full cells exhibit long cyclic life for 2000 cycles with a very high capacity retention of 91.5% at a high rate of 5 C and stable cycling for 350 cycles at a high LFP loading mass of 13.27 mg cm-2.