Converting an O-vacancy-rich oxide into a multifunctional separator modifier for long-lifespan lithium metal batteries

The lithium metal anode is hailed as the desired "holy grail" for the forthcoming generation of highenergy-density batteries,given its astounding theoretical capacity and low potential.Nonetheless,the formation and growth of dendrites seriously compromise battery life and safety.Herein,an yttriastabilized bismuth oxide(YSB) layer is fabricated on the polypropylene(PP) separator,where YSB reacts with Li anode in-situ in the cell to form a multi-component composite interlayer consisting of Li_(3)Bi,Li_(2)O,and Y_(2)O_(3).The interlayer can function not only as a redistributor to regulate Li^(+) distribution but also as an anion adsorber to increase the Li^(+) transference number from 0.37 to 0.79 for suppressing dendrite nucleation and growth.Consequently,compared with the cell with a baseline separator,those with modified separators exhibit prolonged lifespan in both Li/Li symmetrical cells and Li/Cu half-cells.Notably,the full cells coupled with ultrahigh-loading LiFePO_(4) display an excellent cycling performance of 1700 cycles with a high capacity retention of ~80% at 1 C,exhibiting great potential for practical applications.This work provides a feasible and effective new strategy for separator modification towards building a much-anticipated dendrite-free Li anode and realizing long-lifespan lithium metal batteries.

Pressure-induced magnetic phase and structural transition in SmSb_(2)

Motivated by the recent discovery of unconventional superconductivity around a magnetic quantum critical point in pressurized CeSb_(2),here we present a high-pressure study of an isostructural antiferromagnetic(AFM) SmSb_(2) through electrical transport and synchrotron x-ray diffraction measurements.At P_(C)~2.5 GPa,we found a pressure-induced magnetic phase transition accompanied by a Cmca→P4/nmm structural phase transition.In the pristine AFM phase below P_(C),the AFM transition temperature of SmSb_(2) is insensitive to pressure;in the emergent magnetic phase above P_(C),however,the magnetic critical temperature increases rapidly with increasing pressure.In addition,at ambient pressure,the magnetoresistivity(MR) of SmSb_(2) increases suddenly upon cooling below the AFM transition temperature and presents linear nonsaturating behavior under high field at 2 K.With increasing pressure above P_(C),the MR behavior remains similar to that observed at ambient pressure,both in terms of temperature-and field-dependent MR.This leads us to argue an AFM-like state for SmSb_(2) above P_(C).Within the investigated pressure of up to 45.3 GPa and the temperature of down to 1.8 K,we found no signature of superconductivity in SmSb_(2).

A comparison study of alkali metal-doped g-C_3N_4 for visible-light photocatalytic hydrogen evolution

Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage.Graphitic carbon nitride(g‐C3N4)has been a star visible‐light photocatalyst in this field due to its various advantages.However,pristine g‐C3N4usually exhibits limited activity.Herein,to enhance the performance of g‐C3N4,alkali metal ion(Li+,Na+,or K+)‐doped g‐C3N4are prepared via facile high‐temperature treatment.The prepared samples are characterized and analyzed using the technique of XRD,ICP‐AES,SEM,UV‐vis DRS,BET,XPS,PL,TRPL,photoelectrochemical measurements,photocatalytic tests,etc.The resultant doped photocatalysts show enhanced visible‐light photocatalytic activities for hydrogen production,benefiting from the increased specific surface areas(which provide more active sites),decreased band gaps for extended visible‐light absorption,and improved electronic structures for efficient charge transfer.In particular,because of the optimal tuning of both microstructure and electronic structure,the Na‐doped g‐C3N4shows the most effective utilization of photogenerated electrons during the water reduction process.As a result,the highest photocatalytic performance is achieved over the Na‐doped g‐C3N4photocatalyst(18.7?mol/h),3.7times that of pristine g‐C3N4(5.0?mol/h).This work gives a systematic study for the understanding of doping effect of alkali metals in semiconductor photocatalysis.

Normobaric oxygen for cerebral ischemic injury

Oxygen inhalation has been shown to increase oxygen supply to tissues after cerebral ischemia/ reperfusion injury, protecting injured neural cells. However, hyperbaric oxygen may aggravate oxi- dative stress. By contrast, normobaric oxygen has the rapid and non-invasive characteristics and may have therapeutic effects on ischemic/hypoxic disease. Rats inhaled normobaric oxygen （95% 02） for 6 consecutive days, and then a rat model of focal cerebral ischemia was established. Nisst and 2,3,5-triphenyltetrazolium chloride （TTC） staining revealed that normobaric oxygen pretreat- ment improved neurological deficits and reduced infarct volume. Immunohistochemical staining and western blot assay revealed that the expression of hypoxia-inducible factor-la, Notch-l, vascular endothelial growth factor and erythropoietin were increased. Behavioral studies also verified that neurological deficit scores increased. The hypoxia-inducible factor inhibitor 2-methoxyestradiol treatment at 1 hour before administration of normobaric oxygen could suppress the protective effect of normobaric oxygen. Given these observations, normobaric oxygen pretreatment may alleviate cerebral ischemic injury via the hypoxia-inducible factor signal pathway.

Dendrite‐free lithium and sodium metal anodes with deep plating/stripping properties for lithium and sodium batteries

Although lithium(Li)and sodium(Na)metals can be selected as the promising anode materials for next‐generation rechargeable batteries of high energy density,their practical applications are greatly restricted by the uncontrollable dendrite growth.Herein,a platinum(Pt)–copper(Cu)alloycoated Cu foam(Pt–Cu foam)is prepared and then used as the substrate for Li and Na metal anodes.Owing to the ultrarough morphology with a threedimensional porous structure and the quite large surface area as well as lithiophilicity and sodiophilicity,both Li and Na dendrite growths are significantly suppressed on the substrate.Moreover,during Li plating,the lithiated Pt atoms can dissolve into Li phase,leaving a lot of microsized holes on the substrate.During Na plating,although the sodiated Pt atoms cannot dissolve into Na phase,the sodiation of Pt atoms elevates many microsized blocks above the current collector.Either the holes or the voids on the surface of Pt–Cu foam what can be extra place for deposited alkali metal,what effectively relaxes the internal stress caused by the volume exchange during Li and Na plating/stripping.Therefore,the symmetric batteries of Li@Pt–Cu foam and Na@Pt–Cu foam have both achieved long‐term cycling stability even at ultrahigh areal capacity at 20 mAh cm−2.

Flesh Color Diversity of Sweet Potato: An Overview of the Composition, Functions, Biosynthesis, and Gene Regulation of the Major Pigments

Sweet potato is a multifunctional root crop and a source of food with many essential nutrients and bioactive compounds.Variations in the flesh color of the diverse sweet potato varieties are attributed to the different phytochemicals and natural pigments they produce.Among them,carotenoids and anthocyanins are the main pigments known for their antioxidant properties which provide a host of health benefits,hence,regarded as a major component of the human diet.In this review,we provide an overview of the major pigments in sweet potato with much emphasis on their biosynthesis,functions,and regulatory control.More-over,current findings on the molecular mechanisms underlying the biosynthesis and accumulation of carotenoids and anthocyanins in sweet potato are discussed.Insights into the composition,biosynthesis,and regulatory control of these major pigments will further advance the biofortification of sweet potato and provide a reference for breeding carotenoid-and anthocyanin-rich varieties.

Structural and electrical transport properties of Dirac-like semimetal PdSn4 under high pressure

We conducted in-situ high-pressure synchrotron x-ray diffraction(XRD) and electrical transport measurements on Dirac-like semimetal Pd Sn4 in diamond anvil cells with quasi-hydrostatic pressure condition up to 44.5 GPa–52.0 GPa. The XRD data show that the ambient orthorhombic phase(Ccca) is stable with pressures to 44.5 GPa, and the lattice parameters and unit-cell volume decrease monotonously upon compression. The temperature dependence of the resistance exhibits a metallic conduction and follows a Fermi-liquid behavior below 50 K, both of which keep unchanged upon compression to 52.0 GPa. The magnetoresistance curve at 5 K maintains a linear feature in a magnetic field range of 2.5 T–7 T with increasing pressure to 20.0 GPa. Our results may provide pressure-transport constraints on the robustness of the Dirac fermions.

Structural and electrical transport properties of charge density wave material LaAgSb_(2)under high pressure

Layered lanthanum silver antimonide LaAgSb_(2)exhibits both charge density wave(CDW)order and Dirac-cone-like band structure at ambient pressure.Here,we systematically investigate the pressure evolution of structural and electronic properties of LaAgSb_(2)single crystal.We show that the CDW order is destabilized under compression,as evidenced by the gradual suppression of magnetoresistance.At P_(C)~22 GPa,synchrotron x-ray diffraction and Raman scattering measurements reveal a structural modification at room-temperature.Meanwhile,the sign change of the Hall coefficient is observed at 5 K.Our results demonstrate the tunability of CDW order in the pressurized LaAgSb_(2)single crystal,which can be helpful for its potential applications in the next-generation devices.

An Introductive Study about CO₂Hydrogenation into Hydrocarbons Using Iron Catalysts

CO2 hydrogenation reaction was performed on precipitated iron catalysts which were promoted by Si, Zn, K and Cu. The optimum SiO2 content in the catalysts is about 15 wt% relative to Fe2O3 mass. With reaction temperature raised, CO2 conversion is increased continually, but CO and CH4 selectivity only fluctuate in a narrow range which is beneficial to the synthesis of C2+ hydrocarbons. Two kinds of catalyst filling constitution were experimentally compared in order to increase the yield of C5+ hydrocarbons.

Crystalline-amorphization-recrystallization structural transition and emergent superconductivity in van der Waals semiconductor SiP under compression

van der Waals(vdW)semiconductors have gained significant attention due to their unique physical properties and promising applications,which are embedded within distinct crystallographic symmetries.Here,we report a pressure-induced crystallineamorphization-recrystallization transition under compression in binary vdW semiconductor SiP.Upon compression to 52 GPa,bulk SiP undergoes a consecutive phase transition from pristine crystalline to amorphous phase,ultimately to recrystallized phase.By employing synchrotron X-ray diffraction experiments in conjunction with high-pressure crystal structure searching techniques,we reveal that the recrystallized Si P hosts a tetragonal structure(space group I4mm)and further transforms partially into a cubic phase(space group Fm3m).Consistently,electrical transport and alternating-current magnetic susceptibility measurements indicate the presence of three superconducting phases,which are embedded in separate crystallographic symmetries—the amorphous,tetragonal,and cubic structures.Furthermore,a high superconducting transition temperature of 12.3 K is observed in its recovered tetragonal phase during decompression.Our findings uncover a novel phase evolution path and elucidate a pressure-engineered structure-property relationship in vdW semiconductor SiP.These results not only offer a new platform to explore the transformation between different structures and functionalities,but also provide new opportunities for the design and exploration of advanced devices based on vdW materials.

Synthesis of an all-carbon conjugated polymeric segment of carbon nanotubes and its application for lithium-ion batteries

The synthesis and potential applications of nanocarbon materials have attracted much attention in recent years.Herein,we report the design and synthesis of a novel all-carbon conjugated polymeric segment of single-walled carbon nanotubes(poly(cyclo-para-phenylene)(PCPP))and its first application as an anode material for lithium-ion batteries.The as-synthesized PCPP was characterized by Raman spectroscopy,Fourier transform infrared(FTIR),and other spectroscopies.The electrochemical characterization results show the suitability of PCPP as an anode material for lithium-ion batteries.Theoretical calculations indicate the unique structural and physical properties of PCPP.The realization of PCPP expands the scope of bottom-up synthesis of uniform carbon nanotube segments and their potential applications as new materials for lithium-ion batteries.

In Situ Inducing Spinel/Rock Salt Phases to Stabilize Ni-Rich Cathode via Sucrose Heat Treatment

Nickel-rich cathode materials have attracted widespread interest due to their high capacity;however,the structure is prone to degradation and collapse during cycling,resulting in poor stability performance and safety,hindering the development of high-nickel cathode materials.Here,we propose a straightforward method to consume oxygen on the surface of primary particles during the high-temperature calcination process of precursors,inducing the coupled rearrangement of surface cations,resulting in the in situ generation of a nano-sized mixed spinel/rock salt defect phase,which is confirmed by high-angle annular dark-field scanning transmission electron microscopy.LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) modified with mixed phase not only can reduce side reactions with the electrolyte,resulting in fewer by-products such as LiF and Li2CO3,preventing the formation of excessively thick cathode-electrolyte interface layers,but also can avoid irreversible phase transitions and prevents lattice mismatches.As a result,the cycling performance has been improved to some extent,benefiting from structural stability.In addition,the special 3-dimensional structure of the spinel phase allows the material surface to expand ion transport channels and enhance multiplicative performance.Therefore,this study provides a new perspective on the modification of highnickel materials and extends the application of nickel-rich materials.

文化协同的三重影响路径——基于阳明心学的心理动力学效应

如何实现组织的文化协同是组织文化管理的重要议题,但现有文献对于该领域的认识有限。本研究以阳明心学推广的典型企业作为研究对象,深入探讨阳明心学的心理动力学效应,形成组织文化协同的三重影响路径。通过研究证据收集、协同路径和协同方式进行提取,将阳明心学的文化协同路径分为下属—上级(上行)、上级—下属(下行)和平级进行探索。基于分层对企业主体心理动力进行探寻,归纳出阳明心学学习在心理动力学方面的三重分层影响路径。研究结果和相关路径讨论显示,本研究对于解读传统文化如何作用于企业具有重要的理论启示。文章最后讨论了本研究的结果和实践意义、现有研究存在的不足以及未来拓展的方向。

中国企业为什么走不远?

通常,人们认为成功企业都是源于它们创造胜地开辟新的商业领域,但其实成功企业的奇迹都是源于创新能力的发挥,这些创新会依赖于技术、资金、人才等因素,可是人才、技术和资金亦需要转化为创新的成果,而能够转化出创新成果则是依赖于企业所具有的明确的战略逻辑。

2019,传统企业的机会

进入2019年,所有的东西都处于不确定性之中。此时,对于企业来说最重要的就是调整认知。可以看到,如今我们所处的市场经营环境已出现四个明显变化。一是多元与个性化。

全球思维,本地行动

中国企业正迎来全球化的营商环境。有人问我:中国企业是不是一定要全球化?我的回答是:要全球化。理由只有一个:不管你做哪一个行业,企业规模多大,一个最根本的挑战就是中国市场已经是全球市场。因此,即便你不走出国门,你的同业仍可能是来自全世界的。

Facilitating Lithium-Ion Diffusion in Layered Cathode Materials by Introducing Li^(+)/Ni^(2+) Antisite Defects for High-Rate Li-Ion Batteries

Li^(+)/Ni^(2+) antisite defects mainly resulting from their similar ionic radii in the layered nickel-rich cathode materials belong to one of cation disordering scenarios.They are commonly considered harmful to the electrochemical properties,so a minimum degree of cation disordering is usually desired.However,this study indicates that LiNi_(0.8)Co_(0.15)Al_(0.05)O_(2)as the key material for Tesla batteries possesses the highest rate capability when there is a minor degree(2.3%)of Li^(+)/Ni^(2+) antisite defects existing in its layered structure.By combining a theoretical calculation,the improvement mechanism is attributed to two effects to decrease the activation barrier for lithium migration:(1)the anchoring of a low fraction of high-valence Ni^(2+) ions in the Li slab pushes uphill the nearest Li^(+)ions and(2)the same fraction of low-valence Li^(+) ions in the Ni slab weakens the repulsive interaction to the Li^(+) ions at the saddle point.

Synthesis of carbon-coated Li4Ti5O12 and its electrochemical performance as anode material for lithium-ion battery

Carbon-coated Li4Ti5O12 sample was synthesized by a sol-gel method. The Li4Tis012 powders were obtained by calcinations of the gels at 750, 800, 850, 900 ℃ at N2 atmosphere. The structure, morphology and electrochemical properties of the materials were characterized by SEM, XRD and charge and discharge. The final product sintered at 850℃ demonstrates excellent performance with a specific capacity of 163.5 mAh/g after 100 cycles at 1C. Furthermore, the discharge specific capacity of the sample can retain 80 mAh/g at 10℃.

A Range Adjusted Measure of Super-Efficiency in Integer-Valued Data Envelopment Analysis with Undesirable Outputs

DEA(data envelopment analysis) models can be divided into two groups: Radial DEA and non-radial DEA, and the latter has higher discriminatory power than the former. The range adjusted measure(RAM) is an effective and widely used non-radial DEA approach. However, to the best of our knowledge, there is no literature on the integer-valued super-efficiency RAM-DEA model,especially when undesirable outputs are included. We first propose an integer-valued RAM-DEA mode with undesirable outputs and then extend this model to an integer-valued super-efficiency RAM-DEA model with undesirable outputs. Compared with other DEA models, the two novel models have many advantages: 1) They are non-oriented and non-radial DEA models, which enable decision makers to simultaneously and non-proportionally improve inputs and outputs;2) They can handle integer-valued variables and undesirable outputs, so the results obtained are more reliable;3) The results can be easily obtained as it is based on linear programming;4) The integer-valued super-efficiency RAM-DEA model with undesirable outputs can be used to accurately rank efficient DMUs. The proposed models are applied to evaluate the efficiency of China’s regional transportation systems(RTSs) considering the number of transport accidents(an undesirable output). The results help decision makers improve the performance of inefficient RTSs and analyze the strengths of efficient RTSs.

Profits and losses from changes in fair value,executive cash compensation and managerial power:Evidence from A-share listed companies in China

According to optimal contracting theory, compensation contracts are effective in solving the agency problem between stockholders and managers. Executive compensation is naturally related to firm performance. However, contracts are not always perfect. Managers may exert influence on the formulation and implementation of compensation contracts by means of their managerial power. As fair value has been introduced into the new accounting standards in China, new concerns have arisen over the relationship between profits and losses from changes in fair value(CFV) and levels of executive compensation.In this study, we find that executive compensation is significantly related to CFV. However, this sensitivity is asymmetric in that increases to compensation due to profits from changes in fair value(PCFV) are higher than reductions to compensation due to losses from changes in fair value(LCFV). Furthermore,we find that managerial power determines the strength of this asymmetry.