The development of aqueous zinc ion battery cathode materials with high capacity and high magnification is still a challenge.Herein,porous vanadium oxide/carbon(p-VO_(x)@C,mainly VO_(2) with a small amount of V_(2)O_(...The development of aqueous zinc ion battery cathode materials with high capacity and high magnification is still a challenge.Herein,porous vanadium oxide/carbon(p-VO_(x)@C,mainly VO_(2) with a small amount of V_(2)O_(3)) core/shell microspheres with oxygen vacancies are facilely fabricated by using a vanadium-based metal-organic framework(MIL-100(V)) as a sacrificial template.This unique structure can improve the conductivity of the VO_(x),accelerate electrolyte diffusion,and suppress structural collapse during circulation.Subsequently,H_(2)O molecules are introduced into the interlayer of VO_(x) through a highly efficient in-situ electrochemical activation process,facilitating the intercalation and diffusion of zinc ions.After the activation,an optimal sample exhibits a high specific capacity of 464.3 mA h g^(-1) at0.2 A g^(-1) and 395.2 mA h g^(-1) at 10 A g^(-1),indicating excellent rate performance.Moreover,the optimal sample maintains a capacity retention of about 89.3% after 2500 cycles at 10 A g^(-1).Density functional theory calculation demonstrates that the presence of oxygen vacancies and intercalated water molecules can significantly reduce the diffusion barrier for zinc ions.In addition,it is proved that the storage of zinc ions in the cathode is achieved by reversible intercalation/extraction during the charge and discharge process through various ex-situ analysis technologies.This work demonstrates that the p-VO_(x)@C has great potential for applications in aqueous ZIBs after electrochemical activation.展开更多
The practical application of magnesium hydride(MgH_(2))was seriously limited by its high desorption temperature and slow desorp-tion kinetics.In this study,a bullet-like catalyst based on vanadium related MOFs(MOFs-V)...The practical application of magnesium hydride(MgH_(2))was seriously limited by its high desorption temperature and slow desorp-tion kinetics.In this study,a bullet-like catalyst based on vanadium related MOFs(MOFs-V)was successfully synthesized and doped with MgH_(2) by ball milling to improve its hydrogen storage performance.Microstructure analysis demonstrated that the as-synthesized MOFs was consisted of V_(2)O_(3) with a bullet-like structure.After adding 7wt%MOFs-V,the initial desorption temperature of MgH_(2) was reduced from 340.0 to 190.6℃.Besides,the MgH_(2)+7wt%MOFs-V composite released 6.4wt%H_(2) within 5 min at 300℃.Hydrogen uptake was started at 60℃under 3200 kPa hydrogen pressure for the 7wt%MOFs-V containing sample.The desorption and absorption apparent activity energies of the MgH_(2)+7wt%MOFs-V composite were calculated to be(98.4±2.9)and(30.3±2.1)kJ·mol^(-1),much lower than(157.5±3.3)and(78.2±3.4)kJ·mol^(−1) for the as-prepared MgH_(2).The MgH_(2)+7wt%MOFs-V composite exhibited superior cyclic property.During the 20 cycles isothermal dehydrogenation and hydrogenation experiments,the hydrogen storage capacity stayed almost unchanged.X-ray diffraction(XRD)and X-ray photoelectron spectrometer(XPS)measurements confirmed the presence of metallic vanadium in the MgH_(2)+7wt%MOFs-V composite,which served as catalytic unit to markedly improve the hydrogen storage properties of Mg/MgH_(2) system.展开更多
目的:鉴于脓毒症的高发病率和高病死率,早期识别高风险患者并及时干预至关重要,而现有死亡风险预测模型在操作、适用性和预测长期预后等方面均存在不足。本研究旨在探讨脓毒症患者死亡的危险因素,构建近期和远期死亡风险预测模型。方法...目的:鉴于脓毒症的高发病率和高病死率,早期识别高风险患者并及时干预至关重要,而现有死亡风险预测模型在操作、适用性和预测长期预后等方面均存在不足。本研究旨在探讨脓毒症患者死亡的危险因素,构建近期和远期死亡风险预测模型。方法:从美国重症监护医学信息数据库IV(Medical Information Mart for Intensive Care-IV,MIMIC-IV)中选取符合脓毒症3.0诊断标准的人群,按7?3的比例随机分为建模组和验证组,分析患者的基线资料。采用单因素Cox回归分析和全子集回归确定脓毒症患者死亡的危险因素并筛选出构建预测模型的变量。分别用时间依赖性曲线下面积(area under the curve,AUC)、校准曲线和决策曲线评估模型的区分度、校准度和临床实用性。结果:共纳入14240例脓毒症患者,28 d和1年病死率分别为21.45%(3054例)和36.50%(5198例)。高龄、女性、高感染相关器官衰竭评分(sepsis-related organ failure assessment,SOFA)、高简明急性生理学评分(simplified acute physiology score II,SAPS II)、心率快、呼吸频率快、脓毒症休克、充血性心力衰竭、慢性阻塞性肺疾病、肝脏疾病、肾脏疾病、糖尿病、恶性肿瘤、高白细胞计数(white blood cell count,WBC)、长凝血酶原时间(prothrombin time,PT)、高血肌酐(serum creatinine,SCr)水平均为脓毒症死亡的危险因素(均P<0.05)。由PT、呼吸频率、体温、合并恶性肿瘤、合并肝脏疾病、脓毒症休克、SAPS II及年龄8个变量构建的模型,其28 d和1年生存的AUC分别为0.717(95%CI 0.710~0.724)和0.716(95%CI 0.707~0.725)。校准曲线和决策曲线表明该模型具有良好的校准度及较好的临床应用价值。结论:基于MIMIC-IV建立的脓毒症患者近期和远期死亡风险预测模型有较好的识别能力,对患者预后风险评估及干预治疗具有一定的临床参考意义。展开更多
Niobium pentoxide(Nb_(2)O_(5))anodes have gained increasing attentions for high-power lithium-ion batteries owing to the outstanding rate capability and high safety.However,Nb2O5 anode suffers poor cycle stability eve...Niobium pentoxide(Nb_(2)O_(5))anodes have gained increasing attentions for high-power lithium-ion batteries owing to the outstanding rate capability and high safety.However,Nb2O5 anode suffers poor cycle stability even after modified and the unrevealed mechanisms have restricted the practical applications.Herein,the over-reduction of Nb5+has been demonstrated to be the critical reason for the capacity loss for the first time.Besides,an effective competitive redox strategy has been developed to solve the rapid capacity decay of Nb_(2)O_(5),which can be achieved by the incorporation of vanadium to form a new rutile VNbO_(4)anode.The highly reversible V^(3+)/V^(2+)redox couple in VNbO_(4)can effectively inhibit the over-reduction of Nb^(5+).Besides,the electron migration from V^(3+)to Nb5+can greatly increase the intrinsic electronic conductivity for VNbO4.As a result,VNbO4 anode delivers a high capacity of 206.1 mAh g^(−1)at 0.1 A g^(−1),as well as remarkable cycle performance with a retention of 93.4%after 2000 cycles at 1.0 A g^(−1).In addition,the assembled lithium-ion capacitor demonstrates a high energy density of 44 Wh kg^(−1)at 5.8 kW kg^(−1).In summary,our work provides a new insight into the design of ultra-fast and durable anodes.展开更多
Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a no...Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a novel negative electrode with superior electrocatalytic activity by tailoring nitrogen functional groups,such as newly formed nitro and pyridinic-N transformed to pyridonic-N,from the prenitrogen-doped electrode.It was experimentally confirmed that an electrode with pyridonic-N and nitro fuctional groups(tailored nitrogen-doped graphite felt,TNGF) has superior electrocatalytic acivity with enhanced electron and mass transfer.Density functional theory calulations demonstrated the pyridonic-N and nitro functional groups promoted the adsorption,charge transfer,and bond formation with the vanadium species,which is consistent with expermental results.In addition,the V2+/V3+redox reaction mechanism on pyridonic-N and nitro functional groups was estabilised based on density functional theory(DFT) results.When TNGF was applied to a VRFB,it enabled enhanced-electrolyte utilization and energy efficiencies(EE) of 57.9% and 64.6%,respectively,at a current density of 250 mA cm^(-2).These results are 18.6% and 8.9% higher than those of VRFB with electrode containing graphitic-N and pyridinicN groups.Interestingly,TNGF-based VRFB still operated with an EE of 59% at a high current density of300 mA cm^(-2).The TNGF-based VRFB exhibited stable cycling performance without noticeable decay of EE over 450 charge-discharge cycles at a current density of 250 mA cm^(-2).The results of this study suggest that introducing pyridonic-N and nitro groups on the electrode is effective for improving the electrochemical performance of VRFBs.展开更多
Vanadium and its derivatives are used in various industries,including steel,metallurgy,pharmaceuticals,and aerospace engineering.Although China has massive reserves of stone coal resources,these resources have low gra...Vanadium and its derivatives are used in various industries,including steel,metallurgy,pharmaceuticals,and aerospace engineering.Although China has massive reserves of stone coal resources,these resources have low grades.Therefore,the effective extraction and recovery of metallic vanadium from stone coal is an important way to realize the efficient resource utilization of stone coal vanadium ore.Herein,Bacillus mucilaginosus was selected as the leaching strain.The vanadium leaching rate reached 35.5%after 20 d of bioleaching under optimal operating conditions.The cumulative vanadium leaching rate in the contact group reached 35.5%,which was higher than that in the noncontact group(9.3%).The metabolites of B.mucilaginosus,such as oxalic,tartaric,citric,and malic acids,dominated in bioleaching,accounting for 73.8%of the vanadium leaching rate.Interestingly,during leaching,the presence of stone coal stimulated the expression of carbonic anhydrase in bacterial cells,and enzyme activity increased by 1.335-1.905 U.Enzyme activity positively promoted the production of metabolite organic acids,and total organic acid content increased by 39.31 mg·L^(-1),resulting in a reduction of 2.51 in the pH of the leaching system with stone coal.This effect favored the leaching of vanadium from stone coal.Atomic force microscopy illustrated that bacterial leaching exacerbated corrosion on the surface of stone coal beyond 10 nm.Our study provides a clear and promising strategy for exploring the bioleaching mechanism from the perspective of microbial enzyme activity and metabolites.展开更多
The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledim...The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH_(4)Cl and KClO_(3) were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO_(3) was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+ and V3+/V2+ reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm^(−2) for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7% from 55.2% for the pristine cell at 260 mA cm^(−2).Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.展开更多
Sodium-based storage devices based on conversion-type metal sulfide anodes have attracted great atten-tion due to their multivalent ion redox reaction ability.However,they also suffer from sodium polysul-fides(NaPSs)s...Sodium-based storage devices based on conversion-type metal sulfide anodes have attracted great atten-tion due to their multivalent ion redox reaction ability.However,they also suffer from sodium polysul-fides(NaPSs)shuttling problems during the sluggish Na^(+) redox process,leading to"voltage failure"and rapid capacity decay.Herein,a metal cobalt-doping vanadium disulfide(Co-VS_(2))is proposed to simulta-neously accelerate the electrochemical reaction of VS_(2) and enhance the bidirectional redox of soluble NaPSs.It is found that the strong adsorption of NaPSs by V-Co alloy nanoparticles formed in situ during the conversion reaction of Co-VS_(2) can effectively inhibit the dissolution and shuttle of NaPSs,and ther-modynamically reduce the formation energy barrier of the reaction path to effectively drive the complete conversion reaction,while the metal transition of Co elements enhances reconversion kinetics to achieve high reversibility.Moreover,Co-VS_(2) also produce abundant sulfur vacancies and unsaturated sulfur edge defects,significantly improve ionic/electron diffusion kinetics.Therefore,the Co-VS_(2) anode exhibits ultrahigh rate capability(562 mA h g^(-1) at 5 A g^(-1)),high initial coulombic efficiency(~90%)and 12,000 ultralong cycle life with capacity retention of 90%in sodium-ion batteries(SIBs),as well as impressive energy/power density(118 Wh kg^(-1)/31,250 W kg^(-1))and over 10.000 stable cycles in sodium-ion hybrid capacitors(SIHCs).Moreover,the pouch cell-type SIHC displays a high-energy density of 102 Wh kg^(-1) and exceed 600 stable cycles.This work deepens the understanding of the electrochemical reaction mechanism of conversion-type metal sulfide anodes and provides a valuable solution to the shuttlingofNaPSs inSIBsandSIHCs.展开更多
Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries(ZIBs)caused by their high capacity and unique layered structure.However,it is extremely challenging to acquire high ...Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries(ZIBs)caused by their high capacity and unique layered structure.However,it is extremely challenging to acquire high electrochemical performance owing to the limited electronic conductivity,sluggish ion kinetics,and severe volume expansion during the insertion/extraction process of Zn^(2+).Herein,a series of V_(2)O_(3)nanospheres embedded N-doped carbon nanofiber structures with various V_(2)O_(3)spherical morphologies(solid,core-shell,hollow)have been designed for the first time by an electrospinning technique followed thermal treatments.The N-doped carbon nanofibers not only improve the electrical conductivity and the structural stability,but also provides encapsulating shells to prevent the vanadium dissolution and aggregation of V_(2)O_(3)particles.Furthermore,the varied morphological structures of V_(2)O_(3)with abundant oxygen vacancies can alleviate the volume change and increase the Zn^(2+)pathway.Besides,the phase transition between V_(2)O_(3)and Zn_XV_(2)O_(5-m)·n H_(2)O in the cycling was also certified.As a result,the as-obtained composite delivers excellent long-term cycle stability and enhanced rate performance for coin cells,which is also confirmed through density functional theory(DFT)calculations.Even assembled into flexible ZIBs,the sample still exhibits superior electrochemical performance,which may afford new design concept for flexible cathode materials of ZIBs.展开更多
Aging is a natural phenomenon characterized by a progressive decline in physiological integrity,leading to a deterioration of cognitive function and increasing the risk of suffering from chronic-degenerative diseases,...Aging is a natural phenomenon characterized by a progressive decline in physiological integrity,leading to a deterioration of cognitive function and increasing the risk of suffering from chronic-degenerative diseases,including cardiovascular diseases,osteoporosis,cancer,diabetes,and neurodegeneration.Aging is considered the major risk factor for Parkinson’s and Alzheimer’s disease develops.Likewise,diabetes and insulin resistance constitute additional risk factors for developing neurodegenerative disorders.Currently,no treatment can effectively reverse these neurodegenerative pathologies.However,some antidiabetic drugs have opened the possibility of being used against neurodegenerative processes.In the previous framework,Vanadium species have demonstrated a notable antidiabetic effect.Our research group evaluated polyoxidovanadates such as decavanadate and metforminium-decavanadate with preventive and corrective activity on neurodegeneration in brain-specific areas from rats with metabolic syndrome.The results suggest that these polyoxidovanadates induce neuronal and cognitive restoration mechanisms.This review aims to describe the therapeutic potential of polyoxidovanadates as insulin-enhancer agents in the brain,constituting a therapeutic alternative for aging and neurodegenerative diseases.展开更多
The parasitic hydrogen evolution reaction(HER)in the negative half-cell of vanadium redox flow batteries(VRFBs)causes severe efficiency losses.Thus,a deeper understanding of this process and the accompanying bubble fo...The parasitic hydrogen evolution reaction(HER)in the negative half-cell of vanadium redox flow batteries(VRFBs)causes severe efficiency losses.Thus,a deeper understanding of this process and the accompanying bubble formation is crucial.This benchmarking study locally analyzes the bubble distribution in thick,porous electrodes for the first time using deep learning-based image segmentation of synchrotron X-ray micro-tomograms.Each large three-dimensional data set was processed precisely in less than one minute while minimizing human errors and pointing out areas of increased HER activity in VRFBs.The study systematically varies the electrode potential and material,concluding that more negative electrode potentials of-200 m V vs.reversible hydrogen electrode(RHE)and lower cause more substantial bubble formation,resulting in bubble fractions of around 15%–20%in carbon felt electrodes.Contrarily,the bubble fractions stay only around 2%in an electrode combining carbon felt and carbon paper.The detected areas with high HER activity,such as the border subregion with more than 30%bubble fraction in carbon felt electrodes,the cutting edges,and preferential spots in the electrode bulk,are potential-independent and suggest that larger electrodes with a higher bulk-to-border ratio might reduce HER-related performance losses.The described combination of electrochemical measurements,local X-ray microtomography,AI-based segmentation,and 3D morphometric analysis is a powerful and novel approach for local bubble analysis in three-dimensional porous electrodes,providing an essential toolkit for a broad community working on bubble-generating electrochemical systems.展开更多
Vanadium oxides,par-ticularly hydrated forms like V_(2)O_(5)·nH_(2)O(VOH),stand out as promising cathode candidates for aqueous zinc ion batteries due to their adjustable layered structure,unique electronic chara...Vanadium oxides,par-ticularly hydrated forms like V_(2)O_(5)·nH_(2)O(VOH),stand out as promising cathode candidates for aqueous zinc ion batteries due to their adjustable layered structure,unique electronic characteristics,and high theoretical capacities.However,challenges such as vanadium dissolution,sluggish Zn^(2+)diffusion kinetics,and low operating voltage still hinder their direct application.In this study,we present a novel vanadium oxide([C_(6)H_(6)N(CH_(3))_(3)]_(1.08)V_(8)O_(20)·0.06H_(2)O,TMPA-VOH),developed by pre-inserting trimethylphenylammonium(TMPA+)cations into VOH.The incorporation of weakly polarized organic cations capitalizes on both ionic pre-intercalation and molecular pre-intercalation effects,resulting in a phase and morphology transition,an expansion of the interlayer distance,extrusion of weakly bonded interlayer water,and a substantial increase in V^(4+)content.These modifications synergistically reduce the electrostatic interactions between Zn^(2+)and the V-O lattice,enhancing structural stability and reaction kinetics during cycling.As a result,TMPA-VOH achieves an elevated open circuit voltage and operation voltage,exhibits a large specific capacity(451 mAh g^(-1)at 0.1 A g^(-1))coupled with high energy efficiency(89%),the significantly-reduced battery polarization,and outstanding rate capability and cycling stability.The concept introduced in this study holds great promise for the development of high-performance oxide-based energy storage materials.展开更多
基金supported by the National Natural Science Foundation of China(Nos.92163118,51972234)。
文摘The development of aqueous zinc ion battery cathode materials with high capacity and high magnification is still a challenge.Herein,porous vanadium oxide/carbon(p-VO_(x)@C,mainly VO_(2) with a small amount of V_(2)O_(3)) core/shell microspheres with oxygen vacancies are facilely fabricated by using a vanadium-based metal-organic framework(MIL-100(V)) as a sacrificial template.This unique structure can improve the conductivity of the VO_(x),accelerate electrolyte diffusion,and suppress structural collapse during circulation.Subsequently,H_(2)O molecules are introduced into the interlayer of VO_(x) through a highly efficient in-situ electrochemical activation process,facilitating the intercalation and diffusion of zinc ions.After the activation,an optimal sample exhibits a high specific capacity of 464.3 mA h g^(-1) at0.2 A g^(-1) and 395.2 mA h g^(-1) at 10 A g^(-1),indicating excellent rate performance.Moreover,the optimal sample maintains a capacity retention of about 89.3% after 2500 cycles at 10 A g^(-1).Density functional theory calculation demonstrates that the presence of oxygen vacancies and intercalated water molecules can significantly reduce the diffusion barrier for zinc ions.In addition,it is proved that the storage of zinc ions in the cathode is achieved by reversible intercalation/extraction during the charge and discharge process through various ex-situ analysis technologies.This work demonstrates that the p-VO_(x)@C has great potential for applications in aqueous ZIBs after electrochemical activation.
基金financially supported by the National Natural Science Foundation of China (No. 51801078)the Natural Science Foundation of Jiangsu Province (No. BK20180986)
文摘The practical application of magnesium hydride(MgH_(2))was seriously limited by its high desorption temperature and slow desorp-tion kinetics.In this study,a bullet-like catalyst based on vanadium related MOFs(MOFs-V)was successfully synthesized and doped with MgH_(2) by ball milling to improve its hydrogen storage performance.Microstructure analysis demonstrated that the as-synthesized MOFs was consisted of V_(2)O_(3) with a bullet-like structure.After adding 7wt%MOFs-V,the initial desorption temperature of MgH_(2) was reduced from 340.0 to 190.6℃.Besides,the MgH_(2)+7wt%MOFs-V composite released 6.4wt%H_(2) within 5 min at 300℃.Hydrogen uptake was started at 60℃under 3200 kPa hydrogen pressure for the 7wt%MOFs-V containing sample.The desorption and absorption apparent activity energies of the MgH_(2)+7wt%MOFs-V composite were calculated to be(98.4±2.9)and(30.3±2.1)kJ·mol^(-1),much lower than(157.5±3.3)and(78.2±3.4)kJ·mol^(−1) for the as-prepared MgH_(2).The MgH_(2)+7wt%MOFs-V composite exhibited superior cyclic property.During the 20 cycles isothermal dehydrogenation and hydrogenation experiments,the hydrogen storage capacity stayed almost unchanged.X-ray diffraction(XRD)and X-ray photoelectron spectrometer(XPS)measurements confirmed the presence of metallic vanadium in the MgH_(2)+7wt%MOFs-V composite,which served as catalytic unit to markedly improve the hydrogen storage properties of Mg/MgH_(2) system.
文摘目的:鉴于脓毒症的高发病率和高病死率,早期识别高风险患者并及时干预至关重要,而现有死亡风险预测模型在操作、适用性和预测长期预后等方面均存在不足。本研究旨在探讨脓毒症患者死亡的危险因素,构建近期和远期死亡风险预测模型。方法:从美国重症监护医学信息数据库IV(Medical Information Mart for Intensive Care-IV,MIMIC-IV)中选取符合脓毒症3.0诊断标准的人群,按7?3的比例随机分为建模组和验证组,分析患者的基线资料。采用单因素Cox回归分析和全子集回归确定脓毒症患者死亡的危险因素并筛选出构建预测模型的变量。分别用时间依赖性曲线下面积(area under the curve,AUC)、校准曲线和决策曲线评估模型的区分度、校准度和临床实用性。结果:共纳入14240例脓毒症患者,28 d和1年病死率分别为21.45%(3054例)和36.50%(5198例)。高龄、女性、高感染相关器官衰竭评分(sepsis-related organ failure assessment,SOFA)、高简明急性生理学评分(simplified acute physiology score II,SAPS II)、心率快、呼吸频率快、脓毒症休克、充血性心力衰竭、慢性阻塞性肺疾病、肝脏疾病、肾脏疾病、糖尿病、恶性肿瘤、高白细胞计数(white blood cell count,WBC)、长凝血酶原时间(prothrombin time,PT)、高血肌酐(serum creatinine,SCr)水平均为脓毒症死亡的危险因素(均P<0.05)。由PT、呼吸频率、体温、合并恶性肿瘤、合并肝脏疾病、脓毒症休克、SAPS II及年龄8个变量构建的模型,其28 d和1年生存的AUC分别为0.717(95%CI 0.710~0.724)和0.716(95%CI 0.707~0.725)。校准曲线和决策曲线表明该模型具有良好的校准度及较好的临床应用价值。结论:基于MIMIC-IV建立的脓毒症患者近期和远期死亡风险预测模型有较好的识别能力,对患者预后风险评估及干预治疗具有一定的临床参考意义。
基金support from National Natural Science Foundation of China(51874142)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2019TQ05L903)Young Elite Scientists Sponsorship Program by CAST(2019QNRC001).
文摘Niobium pentoxide(Nb_(2)O_(5))anodes have gained increasing attentions for high-power lithium-ion batteries owing to the outstanding rate capability and high safety.However,Nb2O5 anode suffers poor cycle stability even after modified and the unrevealed mechanisms have restricted the practical applications.Herein,the over-reduction of Nb5+has been demonstrated to be the critical reason for the capacity loss for the first time.Besides,an effective competitive redox strategy has been developed to solve the rapid capacity decay of Nb_(2)O_(5),which can be achieved by the incorporation of vanadium to form a new rutile VNbO_(4)anode.The highly reversible V^(3+)/V^(2+)redox couple in VNbO_(4)can effectively inhibit the over-reduction of Nb^(5+).Besides,the electron migration from V^(3+)to Nb5+can greatly increase the intrinsic electronic conductivity for VNbO4.As a result,VNbO4 anode delivers a high capacity of 206.1 mAh g^(−1)at 0.1 A g^(−1),as well as remarkable cycle performance with a retention of 93.4%after 2000 cycles at 1.0 A g^(−1).In addition,the assembled lithium-ion capacitor demonstrates a high energy density of 44 Wh kg^(−1)at 5.8 kW kg^(−1).In summary,our work provides a new insight into the design of ultra-fast and durable anodes.
基金financially supported by the Research Program from Korea Institute of Industrial Technology(EM220011)the Technology Innovation Program(20020229,Development of technology for manufacturing catalysts and electrode parts by use of low contents precious metals of rare metals) funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)+2 种基金the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT)(2022R1F1A1072569)supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science,ICT & Future Planning(NRF2020R1C1C1010493)“Regional Innovation Strategy(RIS)” through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(MOE)(2021RIS-004)。
文摘Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a novel negative electrode with superior electrocatalytic activity by tailoring nitrogen functional groups,such as newly formed nitro and pyridinic-N transformed to pyridonic-N,from the prenitrogen-doped electrode.It was experimentally confirmed that an electrode with pyridonic-N and nitro fuctional groups(tailored nitrogen-doped graphite felt,TNGF) has superior electrocatalytic acivity with enhanced electron and mass transfer.Density functional theory calulations demonstrated the pyridonic-N and nitro functional groups promoted the adsorption,charge transfer,and bond formation with the vanadium species,which is consistent with expermental results.In addition,the V2+/V3+redox reaction mechanism on pyridonic-N and nitro functional groups was estabilised based on density functional theory(DFT) results.When TNGF was applied to a VRFB,it enabled enhanced-electrolyte utilization and energy efficiencies(EE) of 57.9% and 64.6%,respectively,at a current density of 250 mA cm^(-2).These results are 18.6% and 8.9% higher than those of VRFB with electrode containing graphitic-N and pyridinicN groups.Interestingly,TNGF-based VRFB still operated with an EE of 59% at a high current density of300 mA cm^(-2).The TNGF-based VRFB exhibited stable cycling performance without noticeable decay of EE over 450 charge-discharge cycles at a current density of 250 mA cm^(-2).The results of this study suggest that introducing pyridonic-N and nitro groups on the electrode is effective for improving the electrochemical performance of VRFBs.
基金This work was financially supported by the National Natural Science Foundation of China(No.51874018)the Open Foundation of State Key Laboratory of Mineral Processing(No.BGRIMM-KJSKL-2022-07).
文摘Vanadium and its derivatives are used in various industries,including steel,metallurgy,pharmaceuticals,and aerospace engineering.Although China has massive reserves of stone coal resources,these resources have low grades.Therefore,the effective extraction and recovery of metallic vanadium from stone coal is an important way to realize the efficient resource utilization of stone coal vanadium ore.Herein,Bacillus mucilaginosus was selected as the leaching strain.The vanadium leaching rate reached 35.5%after 20 d of bioleaching under optimal operating conditions.The cumulative vanadium leaching rate in the contact group reached 35.5%,which was higher than that in the noncontact group(9.3%).The metabolites of B.mucilaginosus,such as oxalic,tartaric,citric,and malic acids,dominated in bioleaching,accounting for 73.8%of the vanadium leaching rate.Interestingly,during leaching,the presence of stone coal stimulated the expression of carbonic anhydrase in bacterial cells,and enzyme activity increased by 1.335-1.905 U.Enzyme activity positively promoted the production of metabolite organic acids,and total organic acid content increased by 39.31 mg·L^(-1),resulting in a reduction of 2.51 in the pH of the leaching system with stone coal.This effect favored the leaching of vanadium from stone coal.Atomic force microscopy illustrated that bacterial leaching exacerbated corrosion on the surface of stone coal beyond 10 nm.Our study provides a clear and promising strategy for exploring the bioleaching mechanism from the perspective of microbial enzyme activity and metabolites.
基金supported by the National Natural Science Foundation of China(No.51872090)Natural Science Foundation of Hebei Province(No.E2019209433,E2022209158)Colleges and Universities in Hebei Province Science and Technology Research Project(No.JZX2024026).
文摘The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH_(4)Cl and KClO_(3) were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO_(3) was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+ and V3+/V2+ reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm^(−2) for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7% from 55.2% for the pristine cell at 260 mA cm^(−2).Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.
基金supported by the National Natural Science Foundation of China(Grant Nos.52072322,22209137,51604250)the Department of Science and Technology of Sichuan Province(CN)(GrantNos.2022YFG0294,23GJHZ0147,23ZDYF0262)Production-Education Integration Demonstration Project of Sichuan Province"Photovoltaic Industry Production-Education Integration Comprehensive Demonstration Base of Sichuan Province"(Sichuan Financial Education[2022]No.106.n)。
文摘Sodium-based storage devices based on conversion-type metal sulfide anodes have attracted great atten-tion due to their multivalent ion redox reaction ability.However,they also suffer from sodium polysul-fides(NaPSs)shuttling problems during the sluggish Na^(+) redox process,leading to"voltage failure"and rapid capacity decay.Herein,a metal cobalt-doping vanadium disulfide(Co-VS_(2))is proposed to simulta-neously accelerate the electrochemical reaction of VS_(2) and enhance the bidirectional redox of soluble NaPSs.It is found that the strong adsorption of NaPSs by V-Co alloy nanoparticles formed in situ during the conversion reaction of Co-VS_(2) can effectively inhibit the dissolution and shuttle of NaPSs,and ther-modynamically reduce the formation energy barrier of the reaction path to effectively drive the complete conversion reaction,while the metal transition of Co elements enhances reconversion kinetics to achieve high reversibility.Moreover,Co-VS_(2) also produce abundant sulfur vacancies and unsaturated sulfur edge defects,significantly improve ionic/electron diffusion kinetics.Therefore,the Co-VS_(2) anode exhibits ultrahigh rate capability(562 mA h g^(-1) at 5 A g^(-1)),high initial coulombic efficiency(~90%)and 12,000 ultralong cycle life with capacity retention of 90%in sodium-ion batteries(SIBs),as well as impressive energy/power density(118 Wh kg^(-1)/31,250 W kg^(-1))and over 10.000 stable cycles in sodium-ion hybrid capacitors(SIHCs).Moreover,the pouch cell-type SIHC displays a high-energy density of 102 Wh kg^(-1) and exceed 600 stable cycles.This work deepens the understanding of the electrochemical reaction mechanism of conversion-type metal sulfide anodes and provides a valuable solution to the shuttlingofNaPSs inSIBsandSIHCs.
基金supported financially by the Natural Science Foundation of Shandong Province,China(grant numbers ZR2020QE067,ZR2020QB117,and ZR2022MB143)the New Colleges and Universities Twenty Foundational Projects of Jinan City,China(grant number 2021GXRC068)+2 种基金the National Natural Science Foundation of China,China(grant number 22208174)The Scientific Research Foundation in Qilu University of Technology(Shandong Academy of Sciences),China(grant numbers 2023PY002)The Talent research project of Qilu University of Technology(Shandong Academy of Sciences),China(grant numbers 2023RCKY013)。
文摘Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries(ZIBs)caused by their high capacity and unique layered structure.However,it is extremely challenging to acquire high electrochemical performance owing to the limited electronic conductivity,sluggish ion kinetics,and severe volume expansion during the insertion/extraction process of Zn^(2+).Herein,a series of V_(2)O_(3)nanospheres embedded N-doped carbon nanofiber structures with various V_(2)O_(3)spherical morphologies(solid,core-shell,hollow)have been designed for the first time by an electrospinning technique followed thermal treatments.The N-doped carbon nanofibers not only improve the electrical conductivity and the structural stability,but also provides encapsulating shells to prevent the vanadium dissolution and aggregation of V_(2)O_(3)particles.Furthermore,the varied morphological structures of V_(2)O_(3)with abundant oxygen vacancies can alleviate the volume change and increase the Zn^(2+)pathway.Besides,the phase transition between V_(2)O_(3)and Zn_XV_(2)O_(5-m)·n H_(2)O in the cycling was also certified.As a result,the as-obtained composite delivers excellent long-term cycle stability and enhanced rate performance for coin cells,which is also confirmed through density functional theory(DFT)calculations.Even assembled into flexible ZIBs,the sample still exhibits superior electrochemical performance,which may afford new design concept for flexible cathode materials of ZIBs.
基金funded by project from National Research System (CONACYT),Mexico (to SIGC)
文摘Aging is a natural phenomenon characterized by a progressive decline in physiological integrity,leading to a deterioration of cognitive function and increasing the risk of suffering from chronic-degenerative diseases,including cardiovascular diseases,osteoporosis,cancer,diabetes,and neurodegeneration.Aging is considered the major risk factor for Parkinson’s and Alzheimer’s disease develops.Likewise,diabetes and insulin resistance constitute additional risk factors for developing neurodegenerative disorders.Currently,no treatment can effectively reverse these neurodegenerative pathologies.However,some antidiabetic drugs have opened the possibility of being used against neurodegenerative processes.In the previous framework,Vanadium species have demonstrated a notable antidiabetic effect.Our research group evaluated polyoxidovanadates such as decavanadate and metforminium-decavanadate with preventive and corrective activity on neurodegeneration in brain-specific areas from rats with metabolic syndrome.The results suggest that these polyoxidovanadates induce neuronal and cognitive restoration mechanisms.This review aims to describe the therapeutic potential of polyoxidovanadates as insulin-enhancer agents in the brain,constituting a therapeutic alternative for aging and neurodegenerative diseases.
基金financial support through a KekuléPh.D.fellowship by the Fonds der Chemischen Industrie(FCI)support from the China Scholarship Council(No.202106950013)。
文摘The parasitic hydrogen evolution reaction(HER)in the negative half-cell of vanadium redox flow batteries(VRFBs)causes severe efficiency losses.Thus,a deeper understanding of this process and the accompanying bubble formation is crucial.This benchmarking study locally analyzes the bubble distribution in thick,porous electrodes for the first time using deep learning-based image segmentation of synchrotron X-ray micro-tomograms.Each large three-dimensional data set was processed precisely in less than one minute while minimizing human errors and pointing out areas of increased HER activity in VRFBs.The study systematically varies the electrode potential and material,concluding that more negative electrode potentials of-200 m V vs.reversible hydrogen electrode(RHE)and lower cause more substantial bubble formation,resulting in bubble fractions of around 15%–20%in carbon felt electrodes.Contrarily,the bubble fractions stay only around 2%in an electrode combining carbon felt and carbon paper.The detected areas with high HER activity,such as the border subregion with more than 30%bubble fraction in carbon felt electrodes,the cutting edges,and preferential spots in the electrode bulk,are potential-independent and suggest that larger electrodes with a higher bulk-to-border ratio might reduce HER-related performance losses.The described combination of electrochemical measurements,local X-ray microtomography,AI-based segmentation,and 3D morphometric analysis is a powerful and novel approach for local bubble analysis in three-dimensional porous electrodes,providing an essential toolkit for a broad community working on bubble-generating electrochemical systems.
基金This work was supported by the National Science Foundation(CBET-1803256)Dr.C.Liu acknowledges the support from National Natural Science Foundation of China(52102277)the Fundamental Research Funds for the Central Universities,conducted by Tongji University.
文摘Vanadium oxides,par-ticularly hydrated forms like V_(2)O_(5)·nH_(2)O(VOH),stand out as promising cathode candidates for aqueous zinc ion batteries due to their adjustable layered structure,unique electronic characteristics,and high theoretical capacities.However,challenges such as vanadium dissolution,sluggish Zn^(2+)diffusion kinetics,and low operating voltage still hinder their direct application.In this study,we present a novel vanadium oxide([C_(6)H_(6)N(CH_(3))_(3)]_(1.08)V_(8)O_(20)·0.06H_(2)O,TMPA-VOH),developed by pre-inserting trimethylphenylammonium(TMPA+)cations into VOH.The incorporation of weakly polarized organic cations capitalizes on both ionic pre-intercalation and molecular pre-intercalation effects,resulting in a phase and morphology transition,an expansion of the interlayer distance,extrusion of weakly bonded interlayer water,and a substantial increase in V^(4+)content.These modifications synergistically reduce the electrostatic interactions between Zn^(2+)and the V-O lattice,enhancing structural stability and reaction kinetics during cycling.As a result,TMPA-VOH achieves an elevated open circuit voltage and operation voltage,exhibits a large specific capacity(451 mAh g^(-1)at 0.1 A g^(-1))coupled with high energy efficiency(89%),the significantly-reduced battery polarization,and outstanding rate capability and cycling stability.The concept introduced in this study holds great promise for the development of high-performance oxide-based energy storage materials.