China is the world’s largest producer of vanadium products,whose major vanadium resource is vanadium slag obtained by smelting vanadium−titanium magnetite ores.The vanadium extraction techniques from vanadium slag ha...China is the world’s largest producer of vanadium products,whose major vanadium resource is vanadium slag obtained by smelting vanadium−titanium magnetite ores.The vanadium extraction techniques from vanadium slag have progressed stepwise toward greenization during the past 30 years in China.This review has systematically summarized these developments and classified the developments into three stages.The early stage is the efficient vanadium extraction techniques such as the sodium roasting−water leaching technique.The developed stage is the clean vanadium extraction techniques including the calcification roasting−acid leaching technique and sub-molten salt technique.The advanced stage is the green vanadium extraction techniques,for example the magnesiation roasting−acid leaching technique.The mechanisms,advantages and disadvantages of industrially applied and literature reported vanadium extraction techniques in each development stage are elaborated from multiple perspectives.Finally,future development directions are pointed out,aiming to inspire green extraction technique of vanadium worldwide.展开更多
The ammonium salt precipitation method is frequently utilized for extracting vanadium from the leaching solution obtained through sodium roasting of vanadium slag.However,Na^(+)and NH_(4)^(+)ions in the vanadium preci...The ammonium salt precipitation method is frequently utilized for extracting vanadium from the leaching solution obtained through sodium roasting of vanadium slag.However,Na^(+)and NH_(4)^(+)ions in the vanadium precipitation solution can not be effectively separated,leading to a large amount of ammonia-nitrogen wastewater which is difficult to treat.In this study,the manganese salt pretreatment process is used to extract vanadium from a sodium roasting leaching solution,enabling the separation of vanadium and sodium.The vanadium extraction product of manganese salt is dissolved in acid to obtain vanadium-containing leaching solution,then vanadium is extracted by hydrolysis and vanadium precipitation,and V_(2)O_(5)is obtained after impurity removal and calcination.The results show that the rate of vanadium extraction by manganese salt is 98.23%.The vanadium extraction product by manganese salt is Mn_(2)V_(2)O_(7),and its sodium content is only 0.167%.Additionally,the acid solubility of vanadium extraction products by manganese salt is 99.52%,and the vanadium precipitation rate of manganese vanadate solution is 92.34%.After the removal of manganese and calcination process,the purity of V_(2)O_(5)product reached 97.73%,with a mere 0.64%loss of vanadium.The Mn_(2)^(+)and NH_(4)^(+)ions in the solution after vanadium precipitation are separated by precipitation method,which reduces the generation of ammonia-nitrogen wastewater.This is conducive to the green and sustainable development of the vanadium industry.展开更多
All-vanadium flow batteries(VFBs)are one of the most promising large-scale energy storage technologies.Conducting an operando quantitative analysis of the polarizations in VFBs under different conditions is essential ...All-vanadium flow batteries(VFBs)are one of the most promising large-scale energy storage technologies.Conducting an operando quantitative analysis of the polarizations in VFBs under different conditions is essential for developing high power density batteries.Here,we employ an operando decoupling method to quantitatively analyze the polarizations in each electrochemical and chemical reaction of VFBs under different catalytic conditions.Results show that the reduction reaction of V^(3+)presents the largest activation polarization,while the reduction reaction of VO_(2)^(+)primarily contributes to concentration polarizations due to the formation of the intermediate product V_(2)O_(3)^(3+).Additionally,it is found that the widely used electrode catalytic methods,incorporating oxygen functional groups and electrodepositing Bi,not only enhance the reaction kinetics but also exacerbate concentration polarizations simultaneously,especially during the discharge process.Specifically,in the battery with the high oxygen-containing electrodes,the negative side still accounts for the majority of activation loss(75.3%)at 200 mA cm^(-2),but it comes down to 36,9% after catalyzing the negative reactions with bismuth.This work provides an effective way to probe the limiting steps in flow batteries under various working conditions and offers insights for effectively enhancing battery performance for future developments.展开更多
The large-scale exploitation of vanadium(Ⅴ) bearing minerals has led to a massive accumulation of Ⅴ tailings, of which Ⅴ pollution poses severe ecological risks. Although the mechanisms of Ⅴ stress to the microbia...The large-scale exploitation of vanadium(Ⅴ) bearing minerals has led to a massive accumulation of Ⅴ tailings, of which Ⅴ pollution poses severe ecological risks. Although the mechanisms of Ⅴ stress to the microbial community have been reported, the influential pathways in a multi-medium-containing system, for example, the soil-tailings-groundwater system,are unknown. The dynamic redox conditions and substance exchange within the system exhibited complex Ⅴ stress on the local microbial communities. In this study, the influence pathways of Ⅴ stress to the microbial community in the soil-tailings-groundwater system were first investigated. High Ⅴ contents were observed in groundwater(139.2 ± 0.15 μg/L) and soil(98.0–323.8 ± 0.02 mg/kg), respectively. Distinct microbial composition was observed for soil and groundwater, where soil showed the highest level of diversity and richness. Firmicutes, Proteobacteria, Actinobacteria, and Acidobacteria were dominant in soil and groundwater with a sum relative abundance of around 80 %. Based on redundancy analysis and structural equation models, Ⅴ was one of the vital driving factors affecting microbial communities. Groundwater microbial communities were influenced by Ⅴ via Cr, dissolved oxygen, and total nitrogen, while Fe, Mn, and total phosphorus were the key mediators for Ⅴ to affect soil microbial communities. Ⅴ affected the microbial community via metabolic pathways related to carbonaceous matter, which was involved in the establishment of survival strategies for metal stress. This study provides novel insights into the influence pathways of Ⅴ on the microorganisms in tailings reservoir for pollution bioremediation.展开更多
The effect of vanadium(V)element on the microstructure and mechanical properties of anchor steel was explored by microstructural characterization and mechanical property tests of anchor steels with different V content...The effect of vanadium(V)element on the microstructure and mechanical properties of anchor steel was explored by microstructural characterization and mechanical property tests of anchor steels with different V contents.The results indicated that the trace addition of V element can generate dispersed VC nanoparticles in the anchor steel and then refine microstructure by inhibiting austenite grain growth.The increase in V content leads to the formation of a larger amount of smaller VC nanoparticles and more refined microstructure.Moreover,the increasing V content in anchor steel causes the volume fraction of ferrite to increase and that of pearlite to decrease continuously,and even leads to the formation of bainite.Accompanied by the microstructure change,the V-treated anchor steels exhibit higher strength compared with the anchor steel without V addition.However,the increased hardness difference between ferrite and pearlite results in poor coordination of deformation between them,leading to a decrease in their plasticity.The impact toughness of anchor steel first increases but then significantly decreases with the increase in V content.The improvement in impact toughness of trace V-treated anchor steel benefits from the enhancement in the band structure after hot rolling,which consumes more energy during the vertical crack propagation process.However,when the V content further increases,the hard and brittle bainite in the anchor steel can facilitate crack initiation and propagation,ultimately resulting in a reduced toughness.展开更多
Vanadium nitride(VN)is a promising pseudocapacitive material due to the high theoretical capacity,rapid redox Faradaic kinetics,and appropriate potential window.Although VN shows large pseudocapacitance in alkaline el...Vanadium nitride(VN)is a promising pseudocapacitive material due to the high theoretical capacity,rapid redox Faradaic kinetics,and appropriate potential window.Although VN shows large pseudocapacitance in alkaline electrolytes,the electrochemical instability and capacity degradation of VN electrode materials present significant challenges for practical applications.Herein,the capacitance decay mechanism of VN is investigated and a simple strategy to improve cycling stability of VN supercapacitor electrodes is proposed by introducing VO_(4)^(3-)anion in KOH electrolytes.Our results show that the VN electrode is electrochemical stabilization between-1.0and-0.4 V(vs.Hg/Hg O reference electrode)in 1.0 MKOH electrolyte,but demonstrates irreversible oxidation and fast capacitance decay in the potential range of-0.4 to0 V.In situ electrochemical measurements reveal that the capacitance decay of VN from-0.4 to 0 V is ascribed to the irreversible oxidation of vanadium(V)of N–V–O species by oxygen(O)of OH^(-).The as-generated oxidization species are subsequently dissolved into KOH electrolytes,thereby undermining the electrochemical stability of VN.However,this irreversible oxidation process could be hindered by introducing VO_(4)^(3-)in KOH electrolytes.A high volumetric specific capacitance of671.9 F.cm^(-3)(1 A.cm^(-3))and excellent cycling stability(120.3%over 1000 cycles)are achieved for VN nanorod electrode in KOH electrolytes containing VO_(4)^(3-).This study not only elucidates the failure mechanism of VN supercapacitor electrodes in alkaline electrolytes,but also provides new insights into enhancing pseudocapacitive energy storage of VN-based electrode materials.展开更多
The sticking behavior of pellets affects the continuity of production in hydrogen-based shaft furnace.The coupling influences of V_(2)O_(5) and reduction temperature on reduction sticking behavior and mechanism evolut...The sticking behavior of pellets affects the continuity of production in hydrogen-based shaft furnace.The coupling influences of V_(2)O_(5) and reduction temperature on reduction sticking behavior and mechanism evolution of pellets under hydrogen atmosphere are investigated.The increase in V_(2)O_(5) addition aggravated the reduction sticking behavior,which is attributed to the combined functions of the development of unique interwoven structure in the metallic iron interconnections at the reduction sticking interface and the deterioration of reduction swelling behavior of pellets.In addition,the strength of metallic iron interconnections enhanced and reduction sticking behavior aggravated with the increase in reduction temperature.Importantly,compared to other reduction temperatures,the reduction sticking behavior of pellets was most significantly aggravated with the increase in V_(2)O_(5) addition at 1000℃.And the values of sticking index increased from 10.22%to 15.36% as the V_(2)O_(5) addition increased from 0 to 1.00 wt.%at 1000℃.展开更多
An approach for coal-based direct reduction of vanadium−titanium magnetite(VTM)raw ore was proposed.Under the optimal reduction conditions with reduction temperature of 1140℃,reduction time of 3 h,C-to-Fe molar ratio...An approach for coal-based direct reduction of vanadium−titanium magnetite(VTM)raw ore was proposed.Under the optimal reduction conditions with reduction temperature of 1140℃,reduction time of 3 h,C-to-Fe molar ratio of 1.2꞉1,and pre-oxidation temperature of 900℃,the iron metallization degree is 97.8%.Ultimately,magnetic separation yields an iron concentrate with an Fe content of 76.78 wt.%and efficiency of 93.41%,while the magnetic separation slag has a Ti grade and recovery of 9.36 wt.%and 87.07%,respectively,with a titanium loss of 12.93%.This new strategy eliminates the beneficiation process of VTM raw ore,effectively reduces the Ti content in the iron concentrate,and improves the comprehensive utilization of valuable metals.展开更多
This investigation evaluated the impact of as-is biochar(BC)and phosphorous(P)-loaded biochar(PBC)(3%)on the growth and biochemical characteristics of rice under exposure to vanadium(V)(60 mg L^(-1)).The results indic...This investigation evaluated the impact of as-is biochar(BC)and phosphorous(P)-loaded biochar(PBC)(3%)on the growth and biochemical characteristics of rice under exposure to vanadium(V)(60 mg L^(-1)).The results indicate that rice plants exposed to a V-only treatment experienced declines in several growth parameters.Conversely,the inclusion of BC and PBC caused noteworthy increases in physiological traits.PBC performed well in stress environments.Specifically,the shoot and root fresh weights increased by 82.86 and 53.33%,respectively,when compared to the V-only treatment.In addition,the SPAD chlorophyll of the shoot increased by 13.05%relative to the V-amended plants.Moreover,including BC and PBC improved the antioxidant enzyme traits of plant shoot and root,such as significant increases in superoxide dismutase(SOD by 56.11 and 117.35%),catalase(CAT by 34.19 and 35.77%),and peroxidase(POD by 25.90 and 18.74%)when compared to V-only amended plants,respectively.These findings strongly suggest that the application of BC and PBC can trigger biochemical pathways that facilitate biomass accumulation in meristematic cells.However,further investigations are required to elucidate the underlying mechanisms responsible for this growth promotion.展开更多
Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not y...Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not yet fully understood.In this study,the V(V)reduction mechanisms with concomitant V isotope fractionation by the Gram-positive bacterium Bacillus subtilis(B.subtilis)and the Gramnegative bacterium Thauera humireducens(T.humireducens)were investigated.Both strains could effectively reduce V(V),removing(90.5%±1.6%)and(93.0%±1.8%)of V(V)respectively from an initial concentration of 50 mg L^(-1) during a 10-day incubation period.V(V)was bioreduced to insoluble vanadium(IV),which was distributed both inside and outside the cells.Electron transfer via cytochrome C,nicotinamide adenine dinucleotide,and glutathione played critical roles in V(V)reduction.Metabolomic analysis showed that differentially enriched metabolites(quinone,biotin,and riboflavin)mediated electron transfer in both strains.The aqueous V in the remaining solution became isotopically heavier as V(V)bioreduction proceeded.The obtained V isotope composition dynamics followed a Rayleigh fractionation model,and the isotope enrichment factor(e)was(–0.54‰±0.04‰)for B.subtilis and(–0.32‰±0.03‰)for T.humireducens,with an insignificant difference.This study provides molecular insights into electron transfer for V(V)bioreduction and reveals V isotope fractionation during this bioprocess,which is helpful for understanding V biogeochemistry and developing novel strategies for V remediation.展开更多
Vanadium redox flow batteries(VRFBs)hold significant promise for large-scale energy storage applications.However,the sluggish reaction kinetics on the electrode surface considerably limit their performance.Implementat...Vanadium redox flow batteries(VRFBs)hold significant promise for large-scale energy storage applications.However,the sluggish reaction kinetics on the electrode surface considerably limit their performance.Implementation of efficient surface modification on carbon electrodes through an economically viable production method is crucial for the practical application of VRFBs.Herein,a nano-carbon layer with morphology of fine nanoparticles(<90 nm)and rich oxygen functional groups was constructed on carbon felts by unbalanced magnetron sputtering coupled with thermal treatment.This modified carbon felt served as both anode and cathode in cell,enabling an improved wettability of electrolyte and high reversibility of the active mass,and promoted kinetics of redox reactions.The optimized carbon felt,achieved through one hour of deposition(1C-CF),demonstrated outstanding electrochemical performance in a single cell.The cell exhibited a high energy efficiency of 82.4%at a current density of 100 m A cm^(-2)and maintained 71.8%at a high current density of 250 mA cm^(-2).Furthermore,the energy efficiency remained at 77.2%during long-term cycling(450 cycles)at a current density of 150 mA cm^(-2),indicating good electrode stability.Our results shed light on the surface design of carbon felt electrodes for the broad application interest of VRFB energy storage systems.展开更多
In recent years,aqueous aluminum ion batteries have been widely studied owing to their abundant energy storage and high theo retical capacity.An in-depth study of vanadium oxide materials is necessary to address the p...In recent years,aqueous aluminum ion batteries have been widely studied owing to their abundant energy storage and high theo retical capacity.An in-depth study of vanadium oxide materials is necessary to address the precipitation of insoluble products covered cathode surface and the slow reaction kinetics.Therefore,a method using a simple one-step hydrothermal preparation and oxalic acid to regulate oxygen vacancies has been reported.A high starting capacity(400 mAh g^(-1))can be achieved by Ov-V2O5,and it is capable of undergoing 200 cycles at 0.4 A g^(-1),with a termination discharge capacity of103 mAh g^(-1).Mechanism analysis demonstrated that metastable structures(AlxV2O5and HxV2O5)were constructed through the insertion of Al^(3+)/H^(+)during discharging,which existed in the lattice intercalation with V2O5.The incorporation of oxygen vacancies lowers the reaction energy barrier while improving the ion transport efficiency.In addition,the metastable structure allows the electrostatic interaction between Al3+and the main backbone to establish protection and optimize the transport channel.In parallel,this work exploits ex-situ characterization and DFT to obtain a profound insight into the instrumental effect of oxygen vacancies in the construction of metastable structures during in-situ electrochemical activation,with a view to better understanding the mechanism of the synergistic participation of Al3+and H+in the reaction.This work not only reports a method for cathode materials to modulate oxygen vacancies,but also lays the foundation for a deeper understanding of the metastable structure of vanadium oxides.展开更多
The all-vanadium redox flow battery(VRFB)plays an important role in the energy transition toward renewable technologies by providing grid-scale energy storage.Their deployment,however,is limited by the lack of membran...The all-vanadium redox flow battery(VRFB)plays an important role in the energy transition toward renewable technologies by providing grid-scale energy storage.Their deployment,however,is limited by the lack of membranes that provide both a high energy efficiency and capacity retention.Typically,the improvement of the battery’s energy efficiency comes at the cost of its capacity retention.Herein,novel N-alkylated and N-benzylated meta-polybenzimidazole(m-PBI)membranes are used to understand the molecular requirements of the polymer electrolyte in a vanadium redox flow battery,providing an important toolbox for future research toward next-generation membrane materials in energy storage devices.The addition of an ethyl side chain to the m-PBI backbone increases its affinity toward the acidic electrolyte,thereby increasing its ionic conductivity and the corresponding energy efficiency of the VRFB cell from 70%to 78%at a current density of 200 mA cm^(-2).In addition,cells equipped with ethylated m-PBI showed better capacity retention than their pristine counterpart,respectively 91%versus 87%,over 200 cycles at 200 mA cm^(-2).The outstanding VRFB cycling performance,together with the low-cost and fluorine-free chemistry of the N-alkylated m-PBI polymer,makes this material a promising membrane to be used in next-generation VRFB systems.展开更多
Although the enhancement of the zinc storage performance of layered vanadium oxides can be realized by the ionic pre-intercalation strategy,it also occupies a large number of active sites and thus fails to release the...Although the enhancement of the zinc storage performance of layered vanadium oxides can be realized by the ionic pre-intercalation strategy,it also occupies a large number of active sites and thus fails to release the full potential of vanadium oxides.Here,vanadium oxide nanobelts with sodium-poor and oxygen defect-rich were constructed by regulating the content of pre-embedded sodium ions to strike a balance between pre-embedded ions and structural stability.The introduction of trace sodium ions not only increases the spacing of vanadium oxide layers but also occupies as few active sites as possible,which provides the possibility of massive storage,rapid diffusion and stabilization of the host structure for zinc ions.Moreover,the abundant oxygen defects transform the ion transport pathway from two-dimensional to three-dimensional,which greatly improves the ion transport rate in the host phase.Due to these advantages,the synthesized vanadium oxide nanobelts exhibit remarkable electrochemical properties,and this work provides a new idea for the design of structurally stable layered vanadium oxides with excellent properties.展开更多
Ni-ion aqueous batteries(NIBs)were considered an important development direction for aqueous batteries due to the high theoretical capacity(913 mA h g^(-1))and volume capacity(8136 mA h cm^(-3))of nickel metal.Herein,...Ni-ion aqueous batteries(NIBs)were considered an important development direction for aqueous batteries due to the high theoretical capacity(913 mA h g^(-1))and volume capacity(8136 mA h cm^(-3))of nickel metal.Herein,an electrolyte additive(dodecyl trimethyl ammonium chloride,DTAC)was used to improve the electrolyte environment,achieve efficient transport of Ni-ion,and combine the intercalated vanadium oxide cathodes to realize novel strategy NIBs.Firstly,the introduction of trace amounts of DTAC improved the high-concentration NiCl_(2)(4.2 M)electrolyte environment and reconstructed the hydrogen bond network.Molecular dynamics(MD)calculations and electrochemical results indicated that DTAC contributed to the desolvation process of Ni^(2+)and the realization of fast dynamics.The results of Ni symmetric cells demonstrated that DTAC enhanced the rapid migration of Ni-ion and achieved longer cycling stability(1750/1500 h at 0.2/0.5 mA cm^(-2)without obvious short circuits).Secondly,the insertion of organic small molecules(pyrrolidine)into vanadium oxide(V_(2)O_(5))to expand the interlayer spacing promoted the Ni-ion storage capacity of the cathodes.The capacity retention rate of Ni full battery after 6000 cycles at 5 A g^(-1)reached 82.17%.This work provided a novel strategy for the development of Ni-ion aqueous batteries.展开更多
Pre-intercalation is the mainstream approach to inhibit the unpredicted structural degradation and the sluggish kinetics of Zn-ions migrating in vanadium oxide cathode of aqueous zinc-ion batteries(AZIBs),which has be...Pre-intercalation is the mainstream approach to inhibit the unpredicted structural degradation and the sluggish kinetics of Zn-ions migrating in vanadium oxide cathode of aqueous zinc-ion batteries(AZIBs),which has been extensively explored over the past 5 years.The functional principles behind the improvement are widely discussed but have been limited to the enlargement of interspace between VO layers.As the different types of ions could change the properties of vanadium oxides in various ways,the review starts with a comprehensive overview of pre-intercalated vanadium oxide cathode with different types of molecules and ions,such as metal ions,water molecules,and non-metallic cations,along with their functional principles and resulting performance.Furthermore,the pre-intercalated vanadium cathodes reported so far are summarized,comparing their interlayer space,capacity,cycling rate,and capacity retention after long cycling.A discussion of the relationship between the interspace and the performance is provided.The widest interspaces could result in the decay of the cycling stability.Based on the data,the optimal interspace is likely to be around 12?indicating that precise control of the interspace is a useful method.However,more consideration is required regarding the other impacts of pre-intercalated ions on vanadium oxide.It is hoped that this review can inspire further understanding of pre-intercalated vanadium oxide cathodes,paving a new pathway to the development of advanced vanadium oxide cathodes with better cycling stability and larger energy density.展开更多
The Jahn-Teller effect of Mn^(3+)brings drastic structural changes to MnO_(2)-based materials and accelerates the destruction and deactivation of the internal structure of the materials,thus leading to severe capacity...The Jahn-Teller effect of Mn^(3+)brings drastic structural changes to MnO_(2)-based materials and accelerates the destruction and deactivation of the internal structure of the materials,thus leading to severe capacity fading and phase change of MnO_(2)-based materials in aqueous zinc ion batteries(AZIBs).Here,this study doped high valent vanadium ions into MnO_(2)(VMO-x)to inhibit manganese's Jahn-Teller effect.Through a series of characterizations,such as X-ray diffraction(XRD),Raman spectroscopy,and scanning electron microscopy(SEM),it was discovered that the introduction of vanadium ions effectively increased the interlayer spacing of MnO_(2),facilitating the transport of ions into the interlayer.Additionally,Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)demonstrated vanadium doped could effectively adjust the electronic structure,decreasing the average oxidation state of manganese,thereby inhibiting the Jahn-Teller effect and significantly enhancing the stability of the VMO-x cathode.The theoretical calculation showed that introducing vanadium ions enhanced the interaction between the main material and Zn^(2+),optimized its electron transport capacity,and led to better electrical conductivity and reaction kinetics of the VMO-5.Benefiting from this,the VMO-5 cathode exhibited an outstanding capacity of 283 mAh/g and maintained a capacity retention rate of 79%after 2000 cycles,demonstrating excellent electrochemical performance.Furthermore,the mechanism of H^(+)/Zn^(2+)co-intercalation/deintercalation was demonstrated through mechanism analysis.Finally,the test results of the pouch cell demonstrated the excellent flexibility and safety exhibited by the VMO-5 make it have great potential in flexible devices.This work presented a novel approach to doping high valence metal ions into manganese-based electrodes for AZIBs.展开更多
While being a promising candidate for large-scale energy storage,the current market penetration of vanadium redox flow batteries(VRFBs)is still limited by several challenges.As one of the key components in VRFBs,a mem...While being a promising candidate for large-scale energy storage,the current market penetration of vanadium redox flow batteries(VRFBs)is still limited by several challenges.As one of the key components in VRFBs,a membrane is employed to separate the catholyte and anolyte to prevent the vanadium ions from cross-mixing while allowing the proton conduction to maintain charge balance in the system during operation.To overcome the weakness of commercial membranes,various types of membranes,ranging from ion exchange membranes with diverse functional groups to non-ionic porous membranes,have been designed and reported to achieve higher ionic conductivity while maintaining low vanadium ion permeability,thus enhancing efficiency.In addition,besides overall efficiency,stability and cost-effectiveness of the membrane are also critical aspects that determine the practical applicability of the membranes and thus VRFBs.In this article,we have offered comprehensive insights into the mechanism of ion transportation in membranes of VRFBs that contribute to the challenges and issues of VRFB applications.We have further discussed optimal strategies for solving the trade-off between the membrane efficiency and its durability in VRFB applications.The development of state-of-the-art membranes through various material and structure engineering is demonstrated to reveal the relationship of properties-structure-performance.展开更多
Vanadium oxide(VO_(x))has garnered significant attention in the realm of resistive random-access memory(RRAM)owing to its outstanding resistive switching characteristics.However,the ambiguous mechanisms of resistive s...Vanadium oxide(VO_(x))has garnered significant attention in the realm of resistive random-access memory(RRAM)owing to its outstanding resistive switching characteristics.However,the ambiguous mechanisms of resistive switching and inferior stability hinder its practical applications.Herein,an RRAM named VO_(x)/TiO_(2)/n^(++)Si device is prepared.It displays bipolar resistive switching behavior and shows superior cycle endurance(>200),a significantly high on/off ratio(>10^(2))and long-term stability.The tremendous improvement in the stability of the VO_(x)/TiO_(2)/n^(++)Si device compared with the Cu/VOx/n^(++)Si device is due to the p-i-n structure of VO_(x)/TiO_(2)/n^(++)Si.The switching mechanism of the VO_(x)/TiO_(2)/n^(++)Si device is attributed to the growth and annihilation of Cu conductive filaments.展开更多
The phase composition and microstructure of alkaline vanadium slag were characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy(SEM-EDS)and X-ray diffraction(XRD).A crystallization mo...The phase composition and microstructure of alkaline vanadium slag were characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy(SEM-EDS)and X-ray diffraction(XRD).A crystallization model of spinel was established to calculate the effects of basicity(the mass ratio of CaO to SiO_(2))and P_(2)O_(5) on crystal growth rates and precipitation patterns.Based on the crystal size distribution(CSD)theory,the size distribution and growth mechanisms of spinel crystals in alkaline vanadium slag at different temperatures were investigated.The results revealed that,at a cooling rate of 5 K/min,the mean grain size of spinel increased from 12.77 to 21.52μm as the temperature decreased from 1748 to 1598 K,with spinel growth being controlled by the interface.At 1548 K,the spinel particle size reached 31.04μm,indicating a supply-controlled growth mechanism as the temperature decreased from 1598 to 1548 K.Increased P_(2)O_(5) content hindered the crystal growth,while an increase in basicity promoted nucleation and growth.Furthermore,MnCr_(2)O_(4) preferentially crystallized and grew in alkaline vanadium slag.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52074050,52222407)。
文摘China is the world’s largest producer of vanadium products,whose major vanadium resource is vanadium slag obtained by smelting vanadium−titanium magnetite ores.The vanadium extraction techniques from vanadium slag have progressed stepwise toward greenization during the past 30 years in China.This review has systematically summarized these developments and classified the developments into three stages.The early stage is the efficient vanadium extraction techniques such as the sodium roasting−water leaching technique.The developed stage is the clean vanadium extraction techniques including the calcification roasting−acid leaching technique and sub-molten salt technique.The advanced stage is the green vanadium extraction techniques,for example the magnesiation roasting−acid leaching technique.The mechanisms,advantages and disadvantages of industrially applied and literature reported vanadium extraction techniques in each development stage are elaborated from multiple perspectives.Finally,future development directions are pointed out,aiming to inspire green extraction technique of vanadium worldwide.
基金supported by the National Natural Science Foundation of China(52204309,52374300 and 52174277)the Opening Foundation of State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization,China(2022P4FZG11A).
文摘The ammonium salt precipitation method is frequently utilized for extracting vanadium from the leaching solution obtained through sodium roasting of vanadium slag.However,Na^(+)and NH_(4)^(+)ions in the vanadium precipitation solution can not be effectively separated,leading to a large amount of ammonia-nitrogen wastewater which is difficult to treat.In this study,the manganese salt pretreatment process is used to extract vanadium from a sodium roasting leaching solution,enabling the separation of vanadium and sodium.The vanadium extraction product of manganese salt is dissolved in acid to obtain vanadium-containing leaching solution,then vanadium is extracted by hydrolysis and vanadium precipitation,and V_(2)O_(5)is obtained after impurity removal and calcination.The results show that the rate of vanadium extraction by manganese salt is 98.23%.The vanadium extraction product by manganese salt is Mn_(2)V_(2)O_(7),and its sodium content is only 0.167%.Additionally,the acid solubility of vanadium extraction products by manganese salt is 99.52%,and the vanadium precipitation rate of manganese vanadate solution is 92.34%.After the removal of manganese and calcination process,the purity of V_(2)O_(5)product reached 97.73%,with a mere 0.64%loss of vanadium.The Mn_(2)^(+)and NH_(4)^(+)ions in the solution after vanadium precipitation are separated by precipitation method,which reduces the generation of ammonia-nitrogen wastewater.This is conducive to the green and sustainable development of the vanadium industry.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(2023B0303000002)the National Natural Science Foundation of China(No.52206089)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2024A1515010288,2023B1515120005)the Natural Science Foundation of Shenzhen(JCYJ20230807093315033)the Shenzhen Engineering Research Center,Southern University of Science and Technology(No.XMHT20230208003)high level of special funds(G03034K001)。
文摘All-vanadium flow batteries(VFBs)are one of the most promising large-scale energy storage technologies.Conducting an operando quantitative analysis of the polarizations in VFBs under different conditions is essential for developing high power density batteries.Here,we employ an operando decoupling method to quantitatively analyze the polarizations in each electrochemical and chemical reaction of VFBs under different catalytic conditions.Results show that the reduction reaction of V^(3+)presents the largest activation polarization,while the reduction reaction of VO_(2)^(+)primarily contributes to concentration polarizations due to the formation of the intermediate product V_(2)O_(3)^(3+).Additionally,it is found that the widely used electrode catalytic methods,incorporating oxygen functional groups and electrodepositing Bi,not only enhance the reaction kinetics but also exacerbate concentration polarizations simultaneously,especially during the discharge process.Specifically,in the battery with the high oxygen-containing electrodes,the negative side still accounts for the majority of activation loss(75.3%)at 200 mA cm^(-2),but it comes down to 36,9% after catalyzing the negative reactions with bismuth.This work provides an effective way to probe the limiting steps in flow batteries under various working conditions and offers insights for effectively enhancing battery performance for future developments.
基金supported by the National Natural Science Foundation of China(No.42377415)the Natural Science Foundation of Sichuan Province(No.2023NSFSC0811),Sichuan Science and Technology Program(Nos.2021JDTD0013 and 2021YFQ0066)+1 种基金the Science and Technology Major Project of Xizhang Autonomous Region of China(No.XZ202201ZD0004G06)the Everest Scientific Research Program(No.80000-2023ZF11405).
文摘The large-scale exploitation of vanadium(Ⅴ) bearing minerals has led to a massive accumulation of Ⅴ tailings, of which Ⅴ pollution poses severe ecological risks. Although the mechanisms of Ⅴ stress to the microbial community have been reported, the influential pathways in a multi-medium-containing system, for example, the soil-tailings-groundwater system,are unknown. The dynamic redox conditions and substance exchange within the system exhibited complex Ⅴ stress on the local microbial communities. In this study, the influence pathways of Ⅴ stress to the microbial community in the soil-tailings-groundwater system were first investigated. High Ⅴ contents were observed in groundwater(139.2 ± 0.15 μg/L) and soil(98.0–323.8 ± 0.02 mg/kg), respectively. Distinct microbial composition was observed for soil and groundwater, where soil showed the highest level of diversity and richness. Firmicutes, Proteobacteria, Actinobacteria, and Acidobacteria were dominant in soil and groundwater with a sum relative abundance of around 80 %. Based on redundancy analysis and structural equation models, Ⅴ was one of the vital driving factors affecting microbial communities. Groundwater microbial communities were influenced by Ⅴ via Cr, dissolved oxygen, and total nitrogen, while Fe, Mn, and total phosphorus were the key mediators for Ⅴ to affect soil microbial communities. Ⅴ affected the microbial community via metabolic pathways related to carbonaceous matter, which was involved in the establishment of survival strategies for metal stress. This study provides novel insights into the influence pathways of Ⅴ on the microorganisms in tailings reservoir for pollution bioremediation.
基金supported by the National Natural Science Foundation of China(Nos.52101165,52031013 and 52071322).
文摘The effect of vanadium(V)element on the microstructure and mechanical properties of anchor steel was explored by microstructural characterization and mechanical property tests of anchor steels with different V contents.The results indicated that the trace addition of V element can generate dispersed VC nanoparticles in the anchor steel and then refine microstructure by inhibiting austenite grain growth.The increase in V content leads to the formation of a larger amount of smaller VC nanoparticles and more refined microstructure.Moreover,the increasing V content in anchor steel causes the volume fraction of ferrite to increase and that of pearlite to decrease continuously,and even leads to the formation of bainite.Accompanied by the microstructure change,the V-treated anchor steels exhibit higher strength compared with the anchor steel without V addition.However,the increased hardness difference between ferrite and pearlite results in poor coordination of deformation between them,leading to a decrease in their plasticity.The impact toughness of anchor steel first increases but then significantly decreases with the increase in V content.The improvement in impact toughness of trace V-treated anchor steel benefits from the enhancement in the band structure after hot rolling,which consumes more energy during the vertical crack propagation process.However,when the V content further increases,the hard and brittle bainite in the anchor steel can facilitate crack initiation and propagation,ultimately resulting in a reduced toughness.
基金financially supported by the National Natural Science Foundation of China(No.U2004210)Application Foundation Frontier Project of Wuhan Science and Technology Program(No.2020010601012199)City University of Hong Kong Strategic Research Grant,Hong Kong,China(No.7005505)。
文摘Vanadium nitride(VN)is a promising pseudocapacitive material due to the high theoretical capacity,rapid redox Faradaic kinetics,and appropriate potential window.Although VN shows large pseudocapacitance in alkaline electrolytes,the electrochemical instability and capacity degradation of VN electrode materials present significant challenges for practical applications.Herein,the capacitance decay mechanism of VN is investigated and a simple strategy to improve cycling stability of VN supercapacitor electrodes is proposed by introducing VO_(4)^(3-)anion in KOH electrolytes.Our results show that the VN electrode is electrochemical stabilization between-1.0and-0.4 V(vs.Hg/Hg O reference electrode)in 1.0 MKOH electrolyte,but demonstrates irreversible oxidation and fast capacitance decay in the potential range of-0.4 to0 V.In situ electrochemical measurements reveal that the capacitance decay of VN from-0.4 to 0 V is ascribed to the irreversible oxidation of vanadium(V)of N–V–O species by oxygen(O)of OH^(-).The as-generated oxidization species are subsequently dissolved into KOH electrolytes,thereby undermining the electrochemical stability of VN.However,this irreversible oxidation process could be hindered by introducing VO_(4)^(3-)in KOH electrolytes.A high volumetric specific capacitance of671.9 F.cm^(-3)(1 A.cm^(-3))and excellent cycling stability(120.3%over 1000 cycles)are achieved for VN nanorod electrode in KOH electrolytes containing VO_(4)^(3-).This study not only elucidates the failure mechanism of VN supercapacitor electrodes in alkaline electrolytes,but also provides new insights into enhancing pseudocapacitive energy storage of VN-based electrode materials.
基金supported by the authors are especially grateful to the National Natural Science Foundation of China(Grant No.51904063)the Key Program of National Natural Science Foundation of China(No.U23A20608)+6 种基金Fundamental Research Funds for the Central Universities(N2025023,N2225046)Postdoctoral Followship Program of CPSF(GZC20230392)Science&Technology Plan Project of Liaoning Province(2022JH24/10200027)Science&Technology Plan Project of Hebei Province(23314601L)Science and Technology Program of Liaoning of China(2023JH2/101700304)China Postdoctoral Science Foundation(2023M740551)Liaoning Province Science and Technology Plan Joint Program(Key Research and Development Program Project)(2023JH2/101800058).
文摘The sticking behavior of pellets affects the continuity of production in hydrogen-based shaft furnace.The coupling influences of V_(2)O_(5) and reduction temperature on reduction sticking behavior and mechanism evolution of pellets under hydrogen atmosphere are investigated.The increase in V_(2)O_(5) addition aggravated the reduction sticking behavior,which is attributed to the combined functions of the development of unique interwoven structure in the metallic iron interconnections at the reduction sticking interface and the deterioration of reduction swelling behavior of pellets.In addition,the strength of metallic iron interconnections enhanced and reduction sticking behavior aggravated with the increase in reduction temperature.Importantly,compared to other reduction temperatures,the reduction sticking behavior of pellets was most significantly aggravated with the increase in V_(2)O_(5) addition at 1000℃.And the values of sticking index increased from 10.22%to 15.36% as the V_(2)O_(5) addition increased from 0 to 1.00 wt.%at 1000℃.
基金funded by the National Natural Science Foundation of China(Nos.U20A20145,51774205)the Open Project from Engineering Research Center of the Ministry of Education,Sichuan University,China.
文摘An approach for coal-based direct reduction of vanadium−titanium magnetite(VTM)raw ore was proposed.Under the optimal reduction conditions with reduction temperature of 1140℃,reduction time of 3 h,C-to-Fe molar ratio of 1.2꞉1,and pre-oxidation temperature of 900℃,the iron metallization degree is 97.8%.Ultimately,magnetic separation yields an iron concentrate with an Fe content of 76.78 wt.%and efficiency of 93.41%,while the magnetic separation slag has a Ti grade and recovery of 9.36 wt.%and 87.07%,respectively,with a titanium loss of 12.93%.This new strategy eliminates the beneficiation process of VTM raw ore,effectively reduces the Ti content in the iron concentrate,and improves the comprehensive utilization of valuable metals.
基金funded by the Launch Fund of Hainan University High Level Talent,China(RZ2100003226)the National Natural Science Foundation of China(NSFC-31860728).
文摘This investigation evaluated the impact of as-is biochar(BC)and phosphorous(P)-loaded biochar(PBC)(3%)on the growth and biochemical characteristics of rice under exposure to vanadium(V)(60 mg L^(-1)).The results indicate that rice plants exposed to a V-only treatment experienced declines in several growth parameters.Conversely,the inclusion of BC and PBC caused noteworthy increases in physiological traits.PBC performed well in stress environments.Specifically,the shoot and root fresh weights increased by 82.86 and 53.33%,respectively,when compared to the V-only treatment.In addition,the SPAD chlorophyll of the shoot increased by 13.05%relative to the V-amended plants.Moreover,including BC and PBC improved the antioxidant enzyme traits of plant shoot and root,such as significant increases in superoxide dismutase(SOD by 56.11 and 117.35%),catalase(CAT by 34.19 and 35.77%),and peroxidase(POD by 25.90 and 18.74%)when compared to V-only amended plants,respectively.These findings strongly suggest that the application of BC and PBC can trigger biochemical pathways that facilitate biomass accumulation in meristematic cells.However,further investigations are required to elucidate the underlying mechanisms responsible for this growth promotion.
基金supported by the National Natural Science Foundation of China(U21A2033)the Fundamental Research Funds for the Central Universities(2652022103).
文摘Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not yet fully understood.In this study,the V(V)reduction mechanisms with concomitant V isotope fractionation by the Gram-positive bacterium Bacillus subtilis(B.subtilis)and the Gramnegative bacterium Thauera humireducens(T.humireducens)were investigated.Both strains could effectively reduce V(V),removing(90.5%±1.6%)and(93.0%±1.8%)of V(V)respectively from an initial concentration of 50 mg L^(-1) during a 10-day incubation period.V(V)was bioreduced to insoluble vanadium(IV),which was distributed both inside and outside the cells.Electron transfer via cytochrome C,nicotinamide adenine dinucleotide,and glutathione played critical roles in V(V)reduction.Metabolomic analysis showed that differentially enriched metabolites(quinone,biotin,and riboflavin)mediated electron transfer in both strains.The aqueous V in the remaining solution became isotopically heavier as V(V)bioreduction proceeded.The obtained V isotope composition dynamics followed a Rayleigh fractionation model,and the isotope enrichment factor(e)was(–0.54‰±0.04‰)for B.subtilis and(–0.32‰±0.03‰)for T.humireducens,with an insignificant difference.This study provides molecular insights into electron transfer for V(V)bioreduction and reveals V isotope fractionation during this bioprocess,which is helpful for understanding V biogeochemistry and developing novel strategies for V remediation.
基金supported by National Natural Science Foundation of China(U21B2057)。
文摘Vanadium redox flow batteries(VRFBs)hold significant promise for large-scale energy storage applications.However,the sluggish reaction kinetics on the electrode surface considerably limit their performance.Implementation of efficient surface modification on carbon electrodes through an economically viable production method is crucial for the practical application of VRFBs.Herein,a nano-carbon layer with morphology of fine nanoparticles(<90 nm)and rich oxygen functional groups was constructed on carbon felts by unbalanced magnetron sputtering coupled with thermal treatment.This modified carbon felt served as both anode and cathode in cell,enabling an improved wettability of electrolyte and high reversibility of the active mass,and promoted kinetics of redox reactions.The optimized carbon felt,achieved through one hour of deposition(1C-CF),demonstrated outstanding electrochemical performance in a single cell.The cell exhibited a high energy efficiency of 82.4%at a current density of 100 m A cm^(-2)and maintained 71.8%at a high current density of 250 mA cm^(-2).Furthermore,the energy efficiency remained at 77.2%during long-term cycling(450 cycles)at a current density of 150 mA cm^(-2),indicating good electrode stability.Our results shed light on the surface design of carbon felt electrodes for the broad application interest of VRFB energy storage systems.
基金financially supported by the National Natural Science Foundation of China(52102233)Science and Technology Project of Hebei Education Department(QN2023019).
文摘In recent years,aqueous aluminum ion batteries have been widely studied owing to their abundant energy storage and high theo retical capacity.An in-depth study of vanadium oxide materials is necessary to address the precipitation of insoluble products covered cathode surface and the slow reaction kinetics.Therefore,a method using a simple one-step hydrothermal preparation and oxalic acid to regulate oxygen vacancies has been reported.A high starting capacity(400 mAh g^(-1))can be achieved by Ov-V2O5,and it is capable of undergoing 200 cycles at 0.4 A g^(-1),with a termination discharge capacity of103 mAh g^(-1).Mechanism analysis demonstrated that metastable structures(AlxV2O5and HxV2O5)were constructed through the insertion of Al^(3+)/H^(+)during discharging,which existed in the lattice intercalation with V2O5.The incorporation of oxygen vacancies lowers the reaction energy barrier while improving the ion transport efficiency.In addition,the metastable structure allows the electrostatic interaction between Al3+and the main backbone to establish protection and optimize the transport channel.In parallel,this work exploits ex-situ characterization and DFT to obtain a profound insight into the instrumental effect of oxygen vacancies in the construction of metastable structures during in-situ electrochemical activation,with a view to better understanding the mechanism of the synergistic participation of Al3+and H+in the reaction.This work not only reports a method for cathode materials to modulate oxygen vacancies,but also lays the foundation for a deeper understanding of the metastable structure of vanadium oxides.
基金supported by the Swiss National Science Foundation(grant number 188631).
文摘The all-vanadium redox flow battery(VRFB)plays an important role in the energy transition toward renewable technologies by providing grid-scale energy storage.Their deployment,however,is limited by the lack of membranes that provide both a high energy efficiency and capacity retention.Typically,the improvement of the battery’s energy efficiency comes at the cost of its capacity retention.Herein,novel N-alkylated and N-benzylated meta-polybenzimidazole(m-PBI)membranes are used to understand the molecular requirements of the polymer electrolyte in a vanadium redox flow battery,providing an important toolbox for future research toward next-generation membrane materials in energy storage devices.The addition of an ethyl side chain to the m-PBI backbone increases its affinity toward the acidic electrolyte,thereby increasing its ionic conductivity and the corresponding energy efficiency of the VRFB cell from 70%to 78%at a current density of 200 mA cm^(-2).In addition,cells equipped with ethylated m-PBI showed better capacity retention than their pristine counterpart,respectively 91%versus 87%,over 200 cycles at 200 mA cm^(-2).The outstanding VRFB cycling performance,together with the low-cost and fluorine-free chemistry of the N-alkylated m-PBI polymer,makes this material a promising membrane to be used in next-generation VRFB systems.
基金supported by the National Natural Science Foundation of China(No.22179109).
文摘Although the enhancement of the zinc storage performance of layered vanadium oxides can be realized by the ionic pre-intercalation strategy,it also occupies a large number of active sites and thus fails to release the full potential of vanadium oxides.Here,vanadium oxide nanobelts with sodium-poor and oxygen defect-rich were constructed by regulating the content of pre-embedded sodium ions to strike a balance between pre-embedded ions and structural stability.The introduction of trace sodium ions not only increases the spacing of vanadium oxide layers but also occupies as few active sites as possible,which provides the possibility of massive storage,rapid diffusion and stabilization of the host structure for zinc ions.Moreover,the abundant oxygen defects transform the ion transport pathway from two-dimensional to three-dimensional,which greatly improves the ion transport rate in the host phase.Due to these advantages,the synthesized vanadium oxide nanobelts exhibit remarkable electrochemical properties,and this work provides a new idea for the design of structurally stable layered vanadium oxides with excellent properties.
基金financially supported by the National Natural Science Foundation of China(NSFC)(22171030 and 21771028)。
文摘Ni-ion aqueous batteries(NIBs)were considered an important development direction for aqueous batteries due to the high theoretical capacity(913 mA h g^(-1))and volume capacity(8136 mA h cm^(-3))of nickel metal.Herein,an electrolyte additive(dodecyl trimethyl ammonium chloride,DTAC)was used to improve the electrolyte environment,achieve efficient transport of Ni-ion,and combine the intercalated vanadium oxide cathodes to realize novel strategy NIBs.Firstly,the introduction of trace amounts of DTAC improved the high-concentration NiCl_(2)(4.2 M)electrolyte environment and reconstructed the hydrogen bond network.Molecular dynamics(MD)calculations and electrochemical results indicated that DTAC contributed to the desolvation process of Ni^(2+)and the realization of fast dynamics.The results of Ni symmetric cells demonstrated that DTAC enhanced the rapid migration of Ni-ion and achieved longer cycling stability(1750/1500 h at 0.2/0.5 mA cm^(-2)without obvious short circuits).Secondly,the insertion of organic small molecules(pyrrolidine)into vanadium oxide(V_(2)O_(5))to expand the interlayer spacing promoted the Ni-ion storage capacity of the cathodes.The capacity retention rate of Ni full battery after 6000 cycles at 5 A g^(-1)reached 82.17%.This work provided a novel strategy for the development of Ni-ion aqueous batteries.
基金funded by the Startup fund at Hubei University of Technology(Grant Nos.00709)a High-level Talent grant(Grant No.GCC2024012)from Hubei province.
文摘Pre-intercalation is the mainstream approach to inhibit the unpredicted structural degradation and the sluggish kinetics of Zn-ions migrating in vanadium oxide cathode of aqueous zinc-ion batteries(AZIBs),which has been extensively explored over the past 5 years.The functional principles behind the improvement are widely discussed but have been limited to the enlargement of interspace between VO layers.As the different types of ions could change the properties of vanadium oxides in various ways,the review starts with a comprehensive overview of pre-intercalated vanadium oxide cathode with different types of molecules and ions,such as metal ions,water molecules,and non-metallic cations,along with their functional principles and resulting performance.Furthermore,the pre-intercalated vanadium cathodes reported so far are summarized,comparing their interlayer space,capacity,cycling rate,and capacity retention after long cycling.A discussion of the relationship between the interspace and the performance is provided.The widest interspaces could result in the decay of the cycling stability.Based on the data,the optimal interspace is likely to be around 12?indicating that precise control of the interspace is a useful method.However,more consideration is required regarding the other impacts of pre-intercalated ions on vanadium oxide.It is hoped that this review can inspire further understanding of pre-intercalated vanadium oxide cathodes,paving a new pathway to the development of advanced vanadium oxide cathodes with better cycling stability and larger energy density.
基金supported the National Key Research and Development Program of China(No.2024YFA1409900)the National Natural Science Foundation of China(Nos.62101296 and 52303335)+2 种基金the China Postdoctoral Science Foundation(Nos.2021M702656 and 2023M730099)the Natural Science Foundation of Shaanxi Province(Nos.2021JQ-756 and 2021M702656)the Graduate Innovation Fund of the School of Mechanical Engineering,Shaanxi University of Technology(No.SLGJX202404)。
文摘The Jahn-Teller effect of Mn^(3+)brings drastic structural changes to MnO_(2)-based materials and accelerates the destruction and deactivation of the internal structure of the materials,thus leading to severe capacity fading and phase change of MnO_(2)-based materials in aqueous zinc ion batteries(AZIBs).Here,this study doped high valent vanadium ions into MnO_(2)(VMO-x)to inhibit manganese's Jahn-Teller effect.Through a series of characterizations,such as X-ray diffraction(XRD),Raman spectroscopy,and scanning electron microscopy(SEM),it was discovered that the introduction of vanadium ions effectively increased the interlayer spacing of MnO_(2),facilitating the transport of ions into the interlayer.Additionally,Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)demonstrated vanadium doped could effectively adjust the electronic structure,decreasing the average oxidation state of manganese,thereby inhibiting the Jahn-Teller effect and significantly enhancing the stability of the VMO-x cathode.The theoretical calculation showed that introducing vanadium ions enhanced the interaction between the main material and Zn^(2+),optimized its electron transport capacity,and led to better electrical conductivity and reaction kinetics of the VMO-5.Benefiting from this,the VMO-5 cathode exhibited an outstanding capacity of 283 mAh/g and maintained a capacity retention rate of 79%after 2000 cycles,demonstrating excellent electrochemical performance.Furthermore,the mechanism of H^(+)/Zn^(2+)co-intercalation/deintercalation was demonstrated through mechanism analysis.Finally,the test results of the pouch cell demonstrated the excellent flexibility and safety exhibited by the VMO-5 make it have great potential in flexible devices.This work presented a novel approach to doping high valence metal ions into manganese-based electrodes for AZIBs.
基金the financial support from the Australian Research Council(DE220101354,DP240102891)Centre for Materials Science,Queensland University of Technologythe QUT supervisor scholarship and QUT HDR tuition fee sponsorship。
文摘While being a promising candidate for large-scale energy storage,the current market penetration of vanadium redox flow batteries(VRFBs)is still limited by several challenges.As one of the key components in VRFBs,a membrane is employed to separate the catholyte and anolyte to prevent the vanadium ions from cross-mixing while allowing the proton conduction to maintain charge balance in the system during operation.To overcome the weakness of commercial membranes,various types of membranes,ranging from ion exchange membranes with diverse functional groups to non-ionic porous membranes,have been designed and reported to achieve higher ionic conductivity while maintaining low vanadium ion permeability,thus enhancing efficiency.In addition,besides overall efficiency,stability and cost-effectiveness of the membrane are also critical aspects that determine the practical applicability of the membranes and thus VRFBs.In this article,we have offered comprehensive insights into the mechanism of ion transportation in membranes of VRFBs that contribute to the challenges and issues of VRFB applications.We have further discussed optimal strategies for solving the trade-off between the membrane efficiency and its durability in VRFB applications.The development of state-of-the-art membranes through various material and structure engineering is demonstrated to reveal the relationship of properties-structure-performance.
基金National Natural Science Foundation of China(No.61376017)。
文摘Vanadium oxide(VO_(x))has garnered significant attention in the realm of resistive random-access memory(RRAM)owing to its outstanding resistive switching characteristics.However,the ambiguous mechanisms of resistive switching and inferior stability hinder its practical applications.Herein,an RRAM named VO_(x)/TiO_(2)/n^(++)Si device is prepared.It displays bipolar resistive switching behavior and shows superior cycle endurance(>200),a significantly high on/off ratio(>10^(2))and long-term stability.The tremendous improvement in the stability of the VO_(x)/TiO_(2)/n^(++)Si device compared with the Cu/VOx/n^(++)Si device is due to the p-i-n structure of VO_(x)/TiO_(2)/n^(++)Si.The switching mechanism of the VO_(x)/TiO_(2)/n^(++)Si device is attributed to the growth and annihilation of Cu conductive filaments.
基金supported by the National Natural Science Foundation of China(No.51974047)the Natural Science Foundation of Chongqing,China(No.cstc2022ycjh-bgzxm0003)the Large Instrument Foundation of Chongqing University,China(No.202303150239)。
文摘The phase composition and microstructure of alkaline vanadium slag were characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy(SEM-EDS)and X-ray diffraction(XRD).A crystallization model of spinel was established to calculate the effects of basicity(the mass ratio of CaO to SiO_(2))and P_(2)O_(5) on crystal growth rates and precipitation patterns.Based on the crystal size distribution(CSD)theory,the size distribution and growth mechanisms of spinel crystals in alkaline vanadium slag at different temperatures were investigated.The results revealed that,at a cooling rate of 5 K/min,the mean grain size of spinel increased from 12.77 to 21.52μm as the temperature decreased from 1748 to 1598 K,with spinel growth being controlled by the interface.At 1548 K,the spinel particle size reached 31.04μm,indicating a supply-controlled growth mechanism as the temperature decreased from 1598 to 1548 K.Increased P_(2)O_(5) content hindered the crystal growth,while an increase in basicity promoted nucleation and growth.Furthermore,MnCr_(2)O_(4) preferentially crystallized and grew in alkaline vanadium slag.
