Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their ran-dom restacking,2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels wi...Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their ran-dom restacking,2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels with various applications in the absence of proper linking agents.In this work,a rapid spontaneous gelation of Ti3C2Tx MXene with a very low dispersion concentration of 0.5 mg mL^(-1) into multifunctional architectures under moderate centrifugation is illustrated.The as-prepared MXene gels exhibit reconfigurable internal structures and tunable rheological,tribological,electrochemical,infrared-emissive and photothermal-conversion properties based on the pH-induced changes in the surface chemistry of Ti_(3)C_(2)T_(x) nanosheets.By adopting a gel with optimized pH value,high lubrication,exceptional specific capacitances(~635 and~408 F g^(-1) at 5 and 100 mV s^(-1),respectively),long-term capacitance retention(~96.7%after 10,000 cycles)and high-precision screen-or extrusion-printing into different high-resolution anticounterfeiting patterns can be achieved,thus displaying extensive potential applications in the fields of semi-solid lubrication,control-lable devices,supercapacitors,information encryption and infrared camouflaging.展开更多
Molybdenum disulfide/carbon nanotubes assembled by ultrathin nanosheets are synthesized to illustrate the electrolyte salt chemistry via potassium bis-(fluorosulfonyl)imide(KFSI)versus potassium hexafluorophosphate(KP...Molybdenum disulfide/carbon nanotubes assembled by ultrathin nanosheets are synthesized to illustrate the electrolyte salt chemistry via potassium bis-(fluorosulfonyl)imide(KFSI)versus potassium hexafluorophosphate(KPF6).Compared to the case of KPF6,the electrochemical performances using KFSI as the electrolyte salt are greatly improved:~275 mAh g^(−1) after 15,000 cycles at 1 A g^(−1),or~172 mAh g^(−1) even at 40 A g^(−1).These results represent one of the best performances for the reported anode materials.The enhanced performances could be attributed to the FSI-induced changes in the solvate structures,that is,a large solvation energy,a high lowest unoccupied mole cular orbital,and a small bonding dissociation energy of S-F.In this case,a uniform and robust solid-electrolyte interphase(SEI)is produced,improving the mechanical properties and the interface integrity.Then,the uncontrollable fracture and repeated growth of SEI,which always lead to the dissolution of sulfur species and the blockage of charge transfer in the case of KPF6,are well inhibited.This similar enhancement works for other sulfides by KFSI,demonstrating the general importance of this electrolyte salt chemistry.展开更多
Nano-Al13 was separated and purified by four methods to investigate its characteristic,and was analyzed by Al-Ferron timed complexation spectrophotometer,27Al-NMR(nuclear magnetic resonance) ,and transmission electron...Nano-Al13 was separated and purified by four methods to investigate its characteristic,and was analyzed by Al-Ferron timed complexation spectrophotometer,27Al-NMR(nuclear magnetic resonance) ,and transmission electron microscopy(TEM) . Coagulation efficiency of nano-Al13,polyaluminum chloride(PAC) ,and AlCl3 in synthetic water were also investigated by jar test. The dynamic process and aggregation state of kaolin suspensions coagulating with nano-Al13,PAC,and AlCl3 were also investigated. The experimental results indicated that the efficiency of gel column chromatography method was the highest for separating PAC solution with low Al concentration. Ethanol and acetone method was simple and could separated PAC solution with different Al concentrations,while silicon alkylation white block column chromatography method could separate PAC solution only with low Al concentration. The SO42-/Ba2+ displacement method could separate PAC solution with high Al concentration,but extra inorganic cation and anion could be introduced into the solution during the separation. The coagulation efficiency and dynamic experimental results showed that nano-Al13 with a high positive-charged species was the main species of electric neutralization in coagulation process,and it could reduce the turbidity and increase the effiective particles collision rate efflciently in coagulation process. Its coagulation speed and the particle size of coagulant formed were of greatest value in this study.展开更多
Herein,nickel@nitrogen-doped carbon nanotubes(Ni@NCNTs)are prepared by a simple and reliable method with Ni-based complex as single-source precursor.Significantly,the formation of CNTs is not susceptible to the calcin...Herein,nickel@nitrogen-doped carbon nanotubes(Ni@NCNTs)are prepared by a simple and reliable method with Ni-based complex as single-source precursor.Significantly,the formation of CNTs is not susceptible to the calcination temperature and ramping rate and Ni@NCNTs can be attained from 430 to 900℃in an inert atmosphere.Then they are the first time to be applied as the anode material for sodium-ion batteries.The presence of Ni nanoparticles(NPs)facilitates the solid electrolyte interface film over the anode surface and improves the capacity retention of the host material,especially at the high rates.Furthermore,Na+diffusion is reinforced after the introduction of Ni NPs.Ni@NCNTs obtained at 500℃(Ni@NCNTs-500)exhibit the best capacity retention and rate capability.Kinetics analyses demonstrate the faster electron transportation and ion diffusion than others prepared at other temperatures.The surficial capacitance storage favors the fast electrochemistry kinetics.It delivers a high specific capacity(192 mA h g^−1 at 0.5 A g^−1),excellent cycling stability(103 mA h g^−1 after 10,000 cycles at 10 A g^−1),and outstanding high-rate capability up to 20 A g^−1(118 mA h g^−1).The related full cells confirm a high energy density of 140 Wh kg^−1 at 38.16 W kg^−1 and 44.27 W h kg^−1 at 762 W kg^−1.展开更多
The cerium-modified cubic mobil composition of matters 48 (MCM-48) molecular sieves were synthesized using cetyltrimethylammonium bromide (CTAB) as templates at low molar ratio of surfactant to inorganic precursor. X-...The cerium-modified cubic mobil composition of matters 48 (MCM-48) molecular sieves were synthesized using cetyltrimethylammonium bromide (CTAB) as templates at low molar ratio of surfactant to inorganic precursor. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that the well-ordered cubic mesostructure was obtained when the Ce/Si molar ratio is less than 0.05. With the increase of Ce/Si molar ratio, the increase of unit cell parameters and the change of Fourier transform infrared spectroscopy (FTIR) provide powerful evidences for the incorporation of cerium in the framework of mesoporous molecular sieves. Nitrogen sorption data indicate that the Brunauer-Emmett-Teller (BET) surface area and the average pore diameter of Ce(Ⅲ)-MCM-48 are 1288 m 2·g -1 and 4.2 nm, and those of Ce(Ⅳ)-MCM-48 are 1228 m 2·g -1 and 3.7 nm, respectively. Diffuse reflectance UV-visible (UV-vis) spectroscopy confirms the presence of Ce(Ⅲ) in the octahedral position and Ce(Ⅳ) in the fluorite structure. X-ray photoelectron spectroscopy (XPS) studies further reveal that Ce(Ⅲ) and Ce(Ⅳ) coexist in the framework of mesoporous molecular sieves.展开更多
The enthalpies of mixing of L-arginine with 2,2,2-trifluoroethanol and their respective enthalpies of dilution in aqueous solutions at 298.15, 303.15 and 310.15 K were determined as a function of the mole fraction by ...The enthalpies of mixing of L-arginine with 2,2,2-trifluoroethanol and their respective enthalpies of dilution in aqueous solutions at 298.15, 303.15 and 310.15 K were determined as a function of the mole fraction by flow microcalorimetric measurement. These experimental results were analyzed to obtain heterotactic enthalpic interaction coefficients(hxy, hxxy, hxyy) according to the McMillan-Mayer theory. The hxy coefficients between L-arginine molecule studied and 2,2,2-trifluoroethanol molecule in aqueous solutions at 298.15, 303.15 and 310.15 K were found to be all negative. The results were discussed in terms of solute-solute interaction and solute-solvent interaction.展开更多
Aqueous zinc metal batteries feature intrinsic safety,but suffer from severe dendrite growth and water-derived side reactions.Many metal coatings have been explored for stabilizing Zn metal anode via a trialand-error ...Aqueous zinc metal batteries feature intrinsic safety,but suffer from severe dendrite growth and water-derived side reactions.Many metal coatings have been explored for stabilizing Zn metal anode via a trialand-error approach.Here,we propose an exercisable way to screen the potential metal coating on Zn anodes in view of de-polarization effect and dendrite-suppressing ability theoretically.As an output of this screening,cadmium(Cd) metal is checked experimentally.Therefore,symmetric ZnllZn cells using Cd coated Zn(Zn@Cd) exhibit an ultra-long cycle life of 3500 h(nearly 5 months) at a high current density of 10 mA cm^(-2),achieving a record-high cumulative capacity(35 A h cm^(-2)) compared to the previous reports.The full cells of Zn@Cd‖MnO_(2) display a markedly improved cycling performance under harsh conditions including a limited Zn supply(N/P ratio=1.7) and a high areal capacity(3.5 mA h cm^(-2)).The significance of this work lies in not only the first report of Cd coating for stabilizing Zn metal anode,but also a feasible way to screen the promising metal materials for other metal anodes.展开更多
CuFe_2O_4 network,prepared via the electrostatic spray deposition technique,with high reversible capacity and long cycle lifetime for lithium ion battery anode material has been reported.The reversible capacity can be...CuFe_2O_4 network,prepared via the electrostatic spray deposition technique,with high reversible capacity and long cycle lifetime for lithium ion battery anode material has been reported.The reversible capacity can be further enhanced by coating high electronic conductive polypyrrole(PPy).At the current density of 100mA·g^(-1).Li/CuFe_2O_4 electrode delivers a reversible capacity of 842.9 mAh·g^(-1) while the reversible capacity of Li/PPy-coated CuFe_2O_4 electrode increases up to 1106.7 mAh-g~'.A high capacity of 640.7 mAhg"1 for the Li/PPy-coated CuFe_2O_4electrode is maintained in contrast of 398.9 mAh·g^(-1) for CuFe_2O_4 electrode after 60 cycles,which demonstrates good electrochemical performance of the composite due to the increase of electronic conductivity.The electrochemical impedance spectroscopy(EIS) further reveals that the Li/PPy-coated CuFe_2O_4 electrode has a lower charge transfer resistance than the Li/CuFe2C>4 electrode.展开更多
Hollow nanostructures with external shells and inner voids have been proved to greatly shorten the transport distance of ions/electrons and buffer volume change,especially for the large-sized potassium-ions in seconda...Hollow nanostructures with external shells and inner voids have been proved to greatly shorten the transport distance of ions/electrons and buffer volume change,especially for the large-sized potassium-ions in secondary batteries.In this work,hollow carbon(HC) nanospheres embedded with S,P co-doped NiSe_(2)nanoparticles are fabricated by "drop and dry" and "dissolving and precipitation" processes to form Ni(OH)2nanocrystals followed by annealing with S and P dopants to form nanoparticles.The resultant S,P-NiSe_(2)/HC composite exhibits excellent cyclic performance with 131.6 mA h g^(-1)at1000 mA g^(-1)after 3000 cycles for K^(+)storage and a capacity of 417.1 mA h g^(-1)at 1000 mA g^(-1)after1000 cycles for Li^(+)storage.K-ion full cells are assembled and deliver superior cycling stability with a ca pacity of 72.5 mA h g^(-1)at 200 mA g^(-1)after 500 cycles.The hollow carbon shell with excellent electrical conductivity effectively promotes the transporta tion and tolerates large volume variation for both K^(+)and Li^(+).Density functional theory calculations confirm that the S and P co-doping NiSe_(2) enables stronger adsorption of K^(+)ions and higher electrical conductivity that contributes to the improved electrochemical performance.展开更多
La0.68Pb0.32FeO3 samples annealed at different temperature were prepared using citrate sol-gel method. With increasing of annealing temperature from 200 to 1000 ℃, the samples crystallize to have single-phase perovsk...La0.68Pb0.32FeO3 samples annealed at different temperature were prepared using citrate sol-gel method. With increasing of annealing temperature from 200 to 1000 ℃, the samples crystallize to have single-phase perovskite structure. However, the sensitivity increases at first due to the improvement of crystallization of the perovskite phase, and finally drops attributed to the larger grain size. The optimal sensitivities for La0.68Pb0.32FeO3 samples annealed at 400, 600, 800, and 1000 ℃ are 12.14, 14.77, 51.07, and 34.55, respectively.展开更多
Cu-based cathodes in aqueous batteries become very attractive in view of high theoretical capacity,moderate operation voltage and rich reserves of raw materials.However,their applications are obstructed by serious sid...Cu-based cathodes in aqueous batteries become very attractive in view of high theoretical capacity,moderate operation voltage and rich reserves of raw materials.However,their applications are obstructed by serious side reactions.The side reaction mainly arises from the spontaneous formation of Cu_(2)O,which occupies the electrode surface and lowers the reaction reversibility.Here,Na_(2)EDTA is introduced to address these issues.Both experimental results and theoretical calculations indicate that the Na_(2)EDTA reshapes the solvation structure of Cu^(2+)and modifies the electrode/electrolyte interface.Therefore,the redox potential of Cu^(2+)/Cu_(2)O is reduced and the surface of Cu is protected from H2O,thereby inhibiting the formation of Cu_(2)O.Meanwhile,the change in the solvation structure reduces the electrostatic repulsion between Cu^(2+)and the cathode,leading to high local concentration and benefiting uniform deposition.The results shed light on the applications of rechargeable Cu-based batteries.展开更多
Phase boundaries facilitate the charge transportation and alleviate the intrinsic stress upon cycles.Therefore,how to achieve regular phase boundaries is very attractive.Herein,dimer-like Sn-Bi@C nanostructures,where ...Phase boundaries facilitate the charge transportation and alleviate the intrinsic stress upon cycles.Therefore,how to achieve regular phase boundaries is very attractive.Herein,dimer-like Sn-Bi@C nanostructures,where is a well-defined phase boundary between Sn and Bi,have been prepared by a two-step process for the first time.The phase boundary not only provides additional and fast transportation for Na+,but also mitigates the structure stress/strain upon cycling.Therefore,Sn-Bi@C exhibits a high capacity(472.1 m A h g^(-1)at 2 A g^(-1)for 200 cycles),an ultra-long cyclic life(355.6 mA h g^(-1)at 5 A g^(-1)for 4500cycles)and an excellent rate performance(372 mA h g^(-1)at 10 A g^(-1))for sodium storage,much higher than those of Sn@C,Bi@C,and Sn@C+Bi@C.Notably,the full cells of Sn-Bi@C//Na_(3)V_(2)(PO_(4))_(3)/rGO(SnBi@C//NVP/rGO)demonstrate impressive performance(323 mA h g^(-1)at 2 A g^(-1)for 300 cycles).The underlying mechanism for such an excellent performance is elucidated by in-situ X-ray diffraction,exsitu scanning electron microscopy/high-resolution transmission electron microscopy and atomic force microscopy,revealing the good electrode stability and improved mechanical properties of Sn-Bi@C.The synthetic method is extended to dimer-like Sn-Pb@C and Sn-Ag@C heterostructures,which also exhibit the good cycle stability for sodium storage.展开更多
Ino rganic tubular materials have an exceptionally wide range of applications,yet developing a simple and universal method to controllably synthesize them remains challenging.In this work,we report a vaporphase-etchin...Ino rganic tubular materials have an exceptionally wide range of applications,yet developing a simple and universal method to controllably synthesize them remains challenging.In this work,we report a vaporphase-etching hard-template method that can directly fabricate tubes on various thermally stable oxide and sulfide materials.This synthesis method features the introduction of a vapor-phase-etching process to greatly simplify the steps involved in preparing tubular materials and avoids complicated postprocessing procedures.Furthermore,the in-situ heating transmission electron microscopy(TEM)technique is used to observe the dynamic formation process of TiO_(2-x) tubes,indicating that the removal process of the Sb2S3 templates first experienced the Rayleigh instability,then vapor-phase-etching process.When used as an anode for sodium ion batteries,the TiO_(2-x) tube exhibits excellent rate performance of134.6 mA h g^(-1) at the high current density of 10 A g^(-1) and long-term cycling over 7000 cycles.Moreover,the full cell demonstrates excellent cycling performance with capacity retention of 98%after 1000 cycles,indicating that it is a promising anode material for batteries.This method can be expanded to the design and synthesis of other thermally-stable tubular materials such as ZnS,MoS_(2),and SiO_(2).展开更多
Ordered hierarchical architectures are attractive candidates for electrochemical energy storage applications.Herein,a facile self-template strategy is applied to prepare Fe7Se8 architectures with a monolithic structur...Ordered hierarchical architectures are attractive candidates for electrochemical energy storage applications.Herein,a facile self-template strategy is applied to prepare Fe7Se8 architectures with a monolithic structure via a self-synthesized single precursor and subsequent calcination at high temperature.With the support of oleylamine,the precursor is structurally targeted to engineer the Fe7Se8 microstructure,featuring nanorod bundles arranged along the longitudinal direction.Because of their ordered hierarchical structure,the Fe7Se8 nanorod bundles deliver a high reversible capacity of 300 m Ah g^-1 at 0.5 A g^-1,along with exceptional rate capability up to 20 A g^-1 and long-term cycle life over 8000 cycles,which represents the highest stability of Fe7Se8 anodes for sodium-ion batteries reported to date.The feasibility of the present strategy to prepare metal selenide structures highlights its promising potential for the rational and effective engineering of electrode materials responsible for the electrochemical performance of energy storage systems.展开更多
Large scale SnO microhydrangeas are obtained successfully through thermally evaporating of SnO_2 powder wrapped by a filter paper at 1050 and using gold coated Si wafer as the substrate. The as-obtained SnO microhydra...Large scale SnO microhydrangeas are obtained successfully through thermally evaporating of SnO_2 powder wrapped by a filter paper at 1050 and using gold coated Si wafer as the substrate. The as-obtained SnO microhydrangeas are consisted of many thin nanosheets with the thicknesses of 30-60 nm and the diameters of 500-600 nm. A vapor-liquid-solid(VLS) growth mechanism for the as-synthesized SnO microhydrangeas was proposed based on experimental results. Photoluminescence spectrum(PL) shows that there is a strong sharp ultraviolet emission peak at 390 nm, revealing that these three-dimensional SnO microhydrangeas may have potential applications in optoelectronic fields.展开更多
Fast charging and high volumetric capacity are two of the critical demands for sodium-ion batteries(SIBs).Although nanostructured materials achieve outstanding rate performance,they suffer from low tap density and sma...Fast charging and high volumetric capacity are two of the critical demands for sodium-ion batteries(SIBs).Although nanostructured materials achieve outstanding rate performance,they suffer from low tap density and small volumetric capacity.Therefore,how to realize large volumetric capacity and high tap density simultaneously is very challenging.Here,N/F co-doped TiO_(2)/carbon microspheres(NF- TiO_(2)/C)are synthesized to achieve both of them.Theoretical calculations reveal that N and F co-doping increases the contents of oxygen vacancies and narrows the bandgaps of TiO_(2) and C,improving the electronic conductivity of NF- TiO_(2)/C.Furthermore,NF- TiO_(2)/C exhibits the high binding energy and low diffusion energy barrier of Na+,significantly facilitating Na+storage and Na+diffusion.Therefore,NF- TiO_(2)/C offers a high tap density(1.51 g cm^(-3)),an outstanding rate performance(125.9 mAh g^(-1) at 100 C),a large volumetric capacity(190 mAh cm^(-3) at 100 C),a high areal capacity(4.8 mAh cm^(-2))and an ultra-long cycling performance(80.2%after 10,000 cycles at 10 C)simultaneously.In addition,NF- TiO_(2)/C||Na_(3)V_(2)(PO_(4))_(3) full cells achieve an ultrahigh power density of 25.2 kW kg^(-1).These results indicate the great promise of NF- TiO_(2)/C as a high-volumetric-capacity and high-power-density anode material of SIBs.展开更多
Thermo-responsive multiblock polycarbonates were facilely synthesized by covalently binding poly(ethylene glycol)(PEG) and poly(propylene glycol)(PPG) blocks,using triphosgene as coupling agent and pyridine as catalys...Thermo-responsive multiblock polycarbonates were facilely synthesized by covalently binding poly(ethylene glycol)(PEG) and poly(propylene glycol)(PPG) blocks,using triphosgene as coupling agent and pyridine as catalyst.The aqueous solutions of thermo-responsive polycarbonates were investigated by rheological measurements.Steady-state shear measurements reveal that the polycarbonate solutions exhibit shear-thinning behavior and the hydrophilic content has a pronounced effect on the flow behavior of the polycarbonates aqueous solutions.The shear viscosity decreases with increasing poly(ethylene oxide)(PEO) composition.The increase of viscosity with increasing concentration is probably attributed to the formation of stronger network owing to interchain entanglement of PEO block at higher concentration.When the flow curves are fitted to the power law model,flow index is obtained to be less than 1,as exhibiting typical pesudoplastic fluid.The viscoelastic properties of the system also show close dependence on the composition of polycarbonates.Temperature sweep confirms that the multiblock polycarbonates exhibit thermo-responsive properties.For 7% aqueous solution of polycarbonate with composition ratio of EO to PO of 1/1,the sol-gel transition occurs at 37 ℃,which makes the system suitable as an injectable drug delivery system.展开更多
基金This work is financially supported by the Hundred Talents Program of Chinese Academy of Sciences(E30247YB)the Special Talents Program of Lanzhou Institute of Chemical Physics(E0SX0282)+1 种基金the National Natural Science Foundation of Shandong Province(ZR2022QB190)the Innovative Research Funds of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(E1R06SXM07,E1R06SXM09 and E2R06SXM14).
文摘Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their ran-dom restacking,2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels with various applications in the absence of proper linking agents.In this work,a rapid spontaneous gelation of Ti3C2Tx MXene with a very low dispersion concentration of 0.5 mg mL^(-1) into multifunctional architectures under moderate centrifugation is illustrated.The as-prepared MXene gels exhibit reconfigurable internal structures and tunable rheological,tribological,electrochemical,infrared-emissive and photothermal-conversion properties based on the pH-induced changes in the surface chemistry of Ti_(3)C_(2)T_(x) nanosheets.By adopting a gel with optimized pH value,high lubrication,exceptional specific capacitances(~635 and~408 F g^(-1) at 5 and 100 mV s^(-1),respectively),long-term capacitance retention(~96.7%after 10,000 cycles)and high-precision screen-or extrusion-printing into different high-resolution anticounterfeiting patterns can be achieved,thus displaying extensive potential applications in the fields of semi-solid lubrication,control-lable devices,supercapacitors,information encryption and infrared camouflaging.
基金support of the Science,Technology,and Innovation Commission of Shenzhen Municipality(JCYJ20180305000927)the Natural Science Fundamental Research Funds of Shandong University(2018JC023)the Shandong Provincial Natural Science Foundation(ZR2020MB048),and the National Nature Science Foundation of China(No.21971146).
文摘Molybdenum disulfide/carbon nanotubes assembled by ultrathin nanosheets are synthesized to illustrate the electrolyte salt chemistry via potassium bis-(fluorosulfonyl)imide(KFSI)versus potassium hexafluorophosphate(KPF6).Compared to the case of KPF6,the electrochemical performances using KFSI as the electrolyte salt are greatly improved:~275 mAh g^(−1) after 15,000 cycles at 1 A g^(−1),or~172 mAh g^(−1) even at 40 A g^(−1).These results represent one of the best performances for the reported anode materials.The enhanced performances could be attributed to the FSI-induced changes in the solvate structures,that is,a large solvation energy,a high lowest unoccupied mole cular orbital,and a small bonding dissociation energy of S-F.In this case,a uniform and robust solid-electrolyte interphase(SEI)is produced,improving the mechanical properties and the interface integrity.Then,the uncontrollable fracture and repeated growth of SEI,which always lead to the dissolution of sulfur species and the blockage of charge transfer in the case of KPF6,are well inhibited.This similar enhancement works for other sulfides by KFSI,demonstrating the general importance of this electrolyte salt chemistry.
基金supported by the National Natural Sciences Foundation of China (No. 50678095)the Postdoctoral Innovative Projects of Shandong Province (No. 200703053).
文摘Nano-Al13 was separated and purified by four methods to investigate its characteristic,and was analyzed by Al-Ferron timed complexation spectrophotometer,27Al-NMR(nuclear magnetic resonance) ,and transmission electron microscopy(TEM) . Coagulation efficiency of nano-Al13,polyaluminum chloride(PAC) ,and AlCl3 in synthetic water were also investigated by jar test. The dynamic process and aggregation state of kaolin suspensions coagulating with nano-Al13,PAC,and AlCl3 were also investigated. The experimental results indicated that the efficiency of gel column chromatography method was the highest for separating PAC solution with low Al concentration. Ethanol and acetone method was simple and could separated PAC solution with different Al concentrations,while silicon alkylation white block column chromatography method could separate PAC solution only with low Al concentration. The SO42-/Ba2+ displacement method could separate PAC solution with high Al concentration,but extra inorganic cation and anion could be introduced into the solution during the separation. The coagulation efficiency and dynamic experimental results showed that nano-Al13 with a high positive-charged species was the main species of electric neutralization in coagulation process,and it could reduce the turbidity and increase the effiective particles collision rate efflciently in coagulation process. Its coagulation speed and the particle size of coagulant formed were of greatest value in this study.
基金financial supports provided by the National Natural Science Foundation of China(21871164)the Taishan Scholar Project Foundation of Shandong Province(ts20190908)+1 种基金the Natural Science Foundation of Shandong Province(ZR2019MB024)Young Scholars Program of Shandong University(2017WLJH15)。
文摘Herein,nickel@nitrogen-doped carbon nanotubes(Ni@NCNTs)are prepared by a simple and reliable method with Ni-based complex as single-source precursor.Significantly,the formation of CNTs is not susceptible to the calcination temperature and ramping rate and Ni@NCNTs can be attained from 430 to 900℃in an inert atmosphere.Then they are the first time to be applied as the anode material for sodium-ion batteries.The presence of Ni nanoparticles(NPs)facilitates the solid electrolyte interface film over the anode surface and improves the capacity retention of the host material,especially at the high rates.Furthermore,Na+diffusion is reinforced after the introduction of Ni NPs.Ni@NCNTs obtained at 500℃(Ni@NCNTs-500)exhibit the best capacity retention and rate capability.Kinetics analyses demonstrate the faster electron transportation and ion diffusion than others prepared at other temperatures.The surficial capacitance storage favors the fast electrochemistry kinetics.It delivers a high specific capacity(192 mA h g^−1 at 0.5 A g^−1),excellent cycling stability(103 mA h g^−1 after 10,000 cycles at 10 A g^−1),and outstanding high-rate capability up to 20 A g^−1(118 mA h g^−1).The related full cells confirm a high energy density of 140 Wh kg^−1 at 38.16 W kg^−1 and 44.27 W h kg^−1 at 762 W kg^−1.
文摘The cerium-modified cubic mobil composition of matters 48 (MCM-48) molecular sieves were synthesized using cetyltrimethylammonium bromide (CTAB) as templates at low molar ratio of surfactant to inorganic precursor. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that the well-ordered cubic mesostructure was obtained when the Ce/Si molar ratio is less than 0.05. With the increase of Ce/Si molar ratio, the increase of unit cell parameters and the change of Fourier transform infrared spectroscopy (FTIR) provide powerful evidences for the incorporation of cerium in the framework of mesoporous molecular sieves. Nitrogen sorption data indicate that the Brunauer-Emmett-Teller (BET) surface area and the average pore diameter of Ce(Ⅲ)-MCM-48 are 1288 m 2·g -1 and 4.2 nm, and those of Ce(Ⅳ)-MCM-48 are 1228 m 2·g -1 and 3.7 nm, respectively. Diffuse reflectance UV-visible (UV-vis) spectroscopy confirms the presence of Ce(Ⅲ) in the octahedral position and Ce(Ⅳ) in the fluorite structure. X-ray photoelectron spectroscopy (XPS) studies further reveal that Ce(Ⅲ) and Ce(Ⅳ) coexist in the framework of mesoporous molecular sieves.
基金Supported by the Natural Scientific Foundation of Shandong Province, China(NoZ2007B03)the Doctoral Fund of the Ministry of Education of China(New Teachers Fund)(No070422047)
文摘The enthalpies of mixing of L-arginine with 2,2,2-trifluoroethanol and their respective enthalpies of dilution in aqueous solutions at 298.15, 303.15 and 310.15 K were determined as a function of the mole fraction by flow microcalorimetric measurement. These experimental results were analyzed to obtain heterotactic enthalpic interaction coefficients(hxy, hxxy, hxyy) according to the McMillan-Mayer theory. The hxy coefficients between L-arginine molecule studied and 2,2,2-trifluoroethanol molecule in aqueous solutions at 298.15, 303.15 and 310.15 K were found to be all negative. The results were discussed in terms of solute-solute interaction and solute-solvent interaction.
基金supported by the National Nature Science Foundation of China (22105118)the Nature Science Foundation of Shandong Provinces (ZR2021QB095)the China Postdoctoral Science Foundation (2020TQ0183 and 2021M701979)。
文摘Aqueous zinc metal batteries feature intrinsic safety,but suffer from severe dendrite growth and water-derived side reactions.Many metal coatings have been explored for stabilizing Zn metal anode via a trialand-error approach.Here,we propose an exercisable way to screen the potential metal coating on Zn anodes in view of de-polarization effect and dendrite-suppressing ability theoretically.As an output of this screening,cadmium(Cd) metal is checked experimentally.Therefore,symmetric ZnllZn cells using Cd coated Zn(Zn@Cd) exhibit an ultra-long cycle life of 3500 h(nearly 5 months) at a high current density of 10 mA cm^(-2),achieving a record-high cumulative capacity(35 A h cm^(-2)) compared to the previous reports.The full cells of Zn@Cd‖MnO_(2) display a markedly improved cycling performance under harsh conditions including a limited Zn supply(N/P ratio=1.7) and a high areal capacity(3.5 mA h cm^(-2)).The significance of this work lies in not only the first report of Cd coating for stabilizing Zn metal anode,but also a feasible way to screen the promising metal materials for other metal anodes.
基金supported by the 973 Project of China(No.2011CB935901)the National Nature Science Foundations of China(No.21203111,91022033)
文摘CuFe_2O_4 network,prepared via the electrostatic spray deposition technique,with high reversible capacity and long cycle lifetime for lithium ion battery anode material has been reported.The reversible capacity can be further enhanced by coating high electronic conductive polypyrrole(PPy).At the current density of 100mA·g^(-1).Li/CuFe_2O_4 electrode delivers a reversible capacity of 842.9 mAh·g^(-1) while the reversible capacity of Li/PPy-coated CuFe_2O_4 electrode increases up to 1106.7 mAh-g~'.A high capacity of 640.7 mAhg"1 for the Li/PPy-coated CuFe_2O_4electrode is maintained in contrast of 398.9 mAh·g^(-1) for CuFe_2O_4 electrode after 60 cycles,which demonstrates good electrochemical performance of the composite due to the increase of electronic conductivity.The electrochemical impedance spectroscopy(EIS) further reveals that the Li/PPy-coated CuFe_2O_4 electrode has a lower charge transfer resistance than the Li/CuFe2C>4 electrode.
基金financially supported by the Shenzhen Science and Technology Program(JCYJ20220530141012028),ChinaThe National Natural Science Foundation of China(22005178),China+2 种基金The Key Research and Development Program of Shandong Province(2021ZLGX01),ChianThe fellowship of China Postdoctoral Science Foundation(2022M722333),Chianthe Jiangsu Funding Program for Excellent Postdoctoral Talent,Chian。
文摘Hollow nanostructures with external shells and inner voids have been proved to greatly shorten the transport distance of ions/electrons and buffer volume change,especially for the large-sized potassium-ions in secondary batteries.In this work,hollow carbon(HC) nanospheres embedded with S,P co-doped NiSe_(2)nanoparticles are fabricated by "drop and dry" and "dissolving and precipitation" processes to form Ni(OH)2nanocrystals followed by annealing with S and P dopants to form nanoparticles.The resultant S,P-NiSe_(2)/HC composite exhibits excellent cyclic performance with 131.6 mA h g^(-1)at1000 mA g^(-1)after 3000 cycles for K^(+)storage and a capacity of 417.1 mA h g^(-1)at 1000 mA g^(-1)after1000 cycles for Li^(+)storage.K-ion full cells are assembled and deliver superior cycling stability with a ca pacity of 72.5 mA h g^(-1)at 200 mA g^(-1)after 500 cycles.The hollow carbon shell with excellent electrical conductivity effectively promotes the transporta tion and tolerates large volume variation for both K^(+)and Li^(+).Density functional theory calculations confirm that the S and P co-doping NiSe_(2) enables stronger adsorption of K^(+)ions and higher electrical conductivity that contributes to the improved electrochemical performance.
基金Project supported by the National Natural Science Foundation of China (59772040)
文摘La0.68Pb0.32FeO3 samples annealed at different temperature were prepared using citrate sol-gel method. With increasing of annealing temperature from 200 to 1000 ℃, the samples crystallize to have single-phase perovskite structure. However, the sensitivity increases at first due to the improvement of crystallization of the perovskite phase, and finally drops attributed to the larger grain size. The optimal sensitivities for La0.68Pb0.32FeO3 samples annealed at 400, 600, 800, and 1000 ℃ are 12.14, 14.77, 51.07, and 34.55, respectively.
基金financial support from the Natural Science Foundation of Shandong Province(ZR2021ZD05)the Outstanding Talents in Shandong University。
文摘Cu-based cathodes in aqueous batteries become very attractive in view of high theoretical capacity,moderate operation voltage and rich reserves of raw materials.However,their applications are obstructed by serious side reactions.The side reaction mainly arises from the spontaneous formation of Cu_(2)O,which occupies the electrode surface and lowers the reaction reversibility.Here,Na_(2)EDTA is introduced to address these issues.Both experimental results and theoretical calculations indicate that the Na_(2)EDTA reshapes the solvation structure of Cu^(2+)and modifies the electrode/electrolyte interface.Therefore,the redox potential of Cu^(2+)/Cu_(2)O is reduced and the surface of Cu is protected from H2O,thereby inhibiting the formation of Cu_(2)O.Meanwhile,the change in the solvation structure reduces the electrostatic repulsion between Cu^(2+)and the cathode,leading to high local concentration and benefiting uniform deposition.The results shed light on the applications of rechargeable Cu-based batteries.
基金the financial support from Outstanding Youth Scholarship in Shandong University and the Nature Science Foundation of Shandong Province(No.ZR2021MB109)。
文摘Phase boundaries facilitate the charge transportation and alleviate the intrinsic stress upon cycles.Therefore,how to achieve regular phase boundaries is very attractive.Herein,dimer-like Sn-Bi@C nanostructures,where is a well-defined phase boundary between Sn and Bi,have been prepared by a two-step process for the first time.The phase boundary not only provides additional and fast transportation for Na+,but also mitigates the structure stress/strain upon cycling.Therefore,Sn-Bi@C exhibits a high capacity(472.1 m A h g^(-1)at 2 A g^(-1)for 200 cycles),an ultra-long cyclic life(355.6 mA h g^(-1)at 5 A g^(-1)for 4500cycles)and an excellent rate performance(372 mA h g^(-1)at 10 A g^(-1))for sodium storage,much higher than those of Sn@C,Bi@C,and Sn@C+Bi@C.Notably,the full cells of Sn-Bi@C//Na_(3)V_(2)(PO_(4))_(3)/rGO(SnBi@C//NVP/rGO)demonstrate impressive performance(323 mA h g^(-1)at 2 A g^(-1)for 300 cycles).The underlying mechanism for such an excellent performance is elucidated by in-situ X-ray diffraction,exsitu scanning electron microscopy/high-resolution transmission electron microscopy and atomic force microscopy,revealing the good electrode stability and improved mechanical properties of Sn-Bi@C.The synthetic method is extended to dimer-like Sn-Pb@C and Sn-Ag@C heterostructures,which also exhibit the good cycle stability for sodium storage.
基金financial support from the National Natural Science Foundation of China(21971146 and 22272093)the Taishan Scholarship Fund in Shandong Provinces(ts201511004)+2 种基金the Natural Science Foundation of Shandong Province(ZR2021MB127)the operational support of ANSTO staff for synchrotron-based characterizations(Awarded beamtime:AS212/PD/17323)the support from the Australian Research Council(ARC)(DE200101384 and LP180100722)。
文摘Ino rganic tubular materials have an exceptionally wide range of applications,yet developing a simple and universal method to controllably synthesize them remains challenging.In this work,we report a vaporphase-etching hard-template method that can directly fabricate tubes on various thermally stable oxide and sulfide materials.This synthesis method features the introduction of a vapor-phase-etching process to greatly simplify the steps involved in preparing tubular materials and avoids complicated postprocessing procedures.Furthermore,the in-situ heating transmission electron microscopy(TEM)technique is used to observe the dynamic formation process of TiO_(2-x) tubes,indicating that the removal process of the Sb2S3 templates first experienced the Rayleigh instability,then vapor-phase-etching process.When used as an anode for sodium ion batteries,the TiO_(2-x) tube exhibits excellent rate performance of134.6 mA h g^(-1) at the high current density of 10 A g^(-1) and long-term cycling over 7000 cycles.Moreover,the full cell demonstrates excellent cycling performance with capacity retention of 98%after 1000 cycles,indicating that it is a promising anode material for batteries.This method can be expanded to the design and synthesis of other thermally-stable tubular materials such as ZnS,MoS_(2),and SiO_(2).
基金the National Natural Science Foundation of China(21871164)the Natural Science Foundation of Shandong Province(ZR2019MB024)the Taishan Scholar Project of Shandong Province(no.ts201511004).
文摘Ordered hierarchical architectures are attractive candidates for electrochemical energy storage applications.Herein,a facile self-template strategy is applied to prepare Fe7Se8 architectures with a monolithic structure via a self-synthesized single precursor and subsequent calcination at high temperature.With the support of oleylamine,the precursor is structurally targeted to engineer the Fe7Se8 microstructure,featuring nanorod bundles arranged along the longitudinal direction.Because of their ordered hierarchical structure,the Fe7Se8 nanorod bundles deliver a high reversible capacity of 300 m Ah g^-1 at 0.5 A g^-1,along with exceptional rate capability up to 20 A g^-1 and long-term cycle life over 8000 cycles,which represents the highest stability of Fe7Se8 anodes for sodium-ion batteries reported to date.The feasibility of the present strategy to prepare metal selenide structures highlights its promising potential for the rational and effective engineering of electrode materials responsible for the electrochemical performance of energy storage systems.
基金supported by the National Natural Science Foundation of China(No.20773081 and 20873074)National Basic Research Program(No.2007CB808004 and 2009CB930101)Laboratory of Organic Optoelectronic Functional Materials and Molecular Engineering,TIPC,CAS.
基金sponsored by China Postdoctoral Foundation(2012M511016)Special Fund of Postdoctoral Innovation Pro jects in Shandong Province(201201007)Postdoctoral Initiation Foundation of Shandong University and the Foundation for Key Project of Ministry of Education,China(No.211046)
文摘Large scale SnO microhydrangeas are obtained successfully through thermally evaporating of SnO_2 powder wrapped by a filter paper at 1050 and using gold coated Si wafer as the substrate. The as-obtained SnO microhydrangeas are consisted of many thin nanosheets with the thicknesses of 30-60 nm and the diameters of 500-600 nm. A vapor-liquid-solid(VLS) growth mechanism for the as-synthesized SnO microhydrangeas was proposed based on experimental results. Photoluminescence spectrum(PL) shows that there is a strong sharp ultraviolet emission peak at 390 nm, revealing that these three-dimensional SnO microhydrangeas may have potential applications in optoelectronic fields.
基金financial support from the National Nature Science Foundation of China (21971146 and 22105118)the Nature Science Foundation of Shandong Provinces (ZR2021QB095)the China Postdoctoral Science Foundation (2020TQ0183 and 2021M701979)。
文摘Fast charging and high volumetric capacity are two of the critical demands for sodium-ion batteries(SIBs).Although nanostructured materials achieve outstanding rate performance,they suffer from low tap density and small volumetric capacity.Therefore,how to realize large volumetric capacity and high tap density simultaneously is very challenging.Here,N/F co-doped TiO_(2)/carbon microspheres(NF- TiO_(2)/C)are synthesized to achieve both of them.Theoretical calculations reveal that N and F co-doping increases the contents of oxygen vacancies and narrows the bandgaps of TiO_(2) and C,improving the electronic conductivity of NF- TiO_(2)/C.Furthermore,NF- TiO_(2)/C exhibits the high binding energy and low diffusion energy barrier of Na+,significantly facilitating Na+storage and Na+diffusion.Therefore,NF- TiO_(2)/C offers a high tap density(1.51 g cm^(-3)),an outstanding rate performance(125.9 mAh g^(-1) at 100 C),a large volumetric capacity(190 mAh cm^(-3) at 100 C),a high areal capacity(4.8 mAh cm^(-2))and an ultra-long cycling performance(80.2%after 10,000 cycles at 10 C)simultaneously.In addition,NF- TiO_(2)/C||Na_(3)V_(2)(PO_(4))_(3) full cells achieve an ultrahigh power density of 25.2 kW kg^(-1).These results indicate the great promise of NF- TiO_(2)/C as a high-volumetric-capacity and high-power-density anode material of SIBs.
基金Projects(2006GG2203007) supported by the Scientific Research Project of Shandong Province,China
文摘Thermo-responsive multiblock polycarbonates were facilely synthesized by covalently binding poly(ethylene glycol)(PEG) and poly(propylene glycol)(PPG) blocks,using triphosgene as coupling agent and pyridine as catalyst.The aqueous solutions of thermo-responsive polycarbonates were investigated by rheological measurements.Steady-state shear measurements reveal that the polycarbonate solutions exhibit shear-thinning behavior and the hydrophilic content has a pronounced effect on the flow behavior of the polycarbonates aqueous solutions.The shear viscosity decreases with increasing poly(ethylene oxide)(PEO) composition.The increase of viscosity with increasing concentration is probably attributed to the formation of stronger network owing to interchain entanglement of PEO block at higher concentration.When the flow curves are fitted to the power law model,flow index is obtained to be less than 1,as exhibiting typical pesudoplastic fluid.The viscoelastic properties of the system also show close dependence on the composition of polycarbonates.Temperature sweep confirms that the multiblock polycarbonates exhibit thermo-responsive properties.For 7% aqueous solution of polycarbonate with composition ratio of EO to PO of 1/1,the sol-gel transition occurs at 37 ℃,which makes the system suitable as an injectable drug delivery system.