查看更多>>摘要：The global trend towards new energy storage systems has stimulated the development of electrochemical energy storage technologies.Among these technologies,rechargeable aqueous zinc-ion batteries(AZIBs)have attracted considerable interest as a potential alternative to lithium-ion batteries(LIBs)due to their affordable cost,environmental compatibility and high safety standards.In this study,a high-quality electrode for AZIBs has been successfully developed using a dehydrated mixed-valence polyoxometalate-based three-dimensional(3D)inorganic framework material known as[H6Mn3VⅣ15V-Ⅴ4O46(H2O)12](3D-MnVO).This innovative 3D-MnVO material is built from the alternate connections of {V19O46}"sphere-shaped"clusters and p2-{Mn(H2O)4} bridges,where each {V19O46} cluster is surrounded by three pairs of vertically distributed {Mn(H2O)4} units,thus resulting in the 3D interpenetrating grid-like network from the infi-nite[-{V19O46}-μ2-Mn(H2O)4-{V19O46}]∞ chains in three mutually perpendicular directions.The 3D framework structure of 3D-MnVO possesses abundant oxygen vacan-cies,spacious and multi-level interconnected channels for ion transport,which facilitates the efficient intercalation/deintercalation of hydrated Zn2+into the pores of the primary structure via the intercalation capacitance mecha-nism.As a result,the 3D-MnVO electrode exhibits excel-lent diffusion rates and minimal interfacial resistance.At a current density of 0.1 A·g-1,the 3D-MnVO cathode delivers a commendable discharge capacity of 170.5 mAh·g-1 with 81.6％capacity retention after 100 charge/discharge cycles.Furthermore,even at a high current density of 1.0 A·g-1,the 3D-MnVO electrode delivers a remarkable reversible capacity of 198.9 mAh·g-1.Our research results provide valuable insights into the development of advanced polyoxometa-late-based 3D inorganic framework electrode materials for high-performance rechargeable AZIBs.
查看更多>>摘要：Aqueous Zn-ion batteries(AZIBs)have emerged as potential candidates for Li-ion batteries due to their intrinsic safety and high capacity.However,metallic Zn anodes encounter dendrite growth and water-induced corrosion,rendering poor stability and severe irreversibility at the electrode/electrolyte interface during cycling.To stabilize the Zn anode,we report a low-cost and effective nonionic surfactant,Tween-20 polymer,as an electrolyte additive for AZIBs.For Tween-20,sequential oxyethylene groups tended to be preferentially adsorbed on the Zn electrode to form a shielding layer for regulating uniform Zn nucleation.Moreover,the hydrophobic hendecyl chains prevented H2O-induced corrosion on the Zn anode surface.Benefiting from the desired functional groups,when only trace amounts of Tween-20(0.050 g·L-1)were used,the Zn anode displayed good cycling stability over 2170 h at 10 mA·cm-2 and a high average Coulombic efficiency of 98.94％over 1000 cycles.The Tween-20 polymer can also be effectively employed in MnO2/Zn full batteries.Con-sidering their toxicity,price and amount of usage,these surfactant additives provide a promising strategy for real-izing the stability and reversibility of high-performance Zn anodes.
查看更多>>摘要：The highly reversible insertion/extraction of large-radius K+into electrode materials remains a tough goal,especially for conversion-type materials.Herein,we design a current collector-integrated electrode(N-CoSe/CoSe2-C@Cu)as an advanced anode for potassium-ion battery(PIBs).The conductive CoSe/CoSe2 heterojunction with rich Se vacancy defects,conductive sp2 N-doped carbon layer,and the elastic copper foil matrix can greatly accelerate the electron transfer and enhance the structural stability.Consequently,the well-designed N-CoSe/CoSe2-C@Cu current collector-integrated electrode displays enhanced potassium storage performance with regard to a high capacity(325.1 mAh·g-1 at 0.1 A·g-1 after 200 cycles),an exceptional rate capability(223.5 mAh·g-1 at 2000 mA·g-1),and an extraordinary long-term cycle sta-bility(a capacity fading of only 0.019％per cycle over 1200 cycles at 2000 mA·g-1).Impressively,ex situ scan-ning electron microscopy(SEM)characterizations prove that the elastic structure of copper foil is merged into the cleverly designed N-CoSe/CoSe2-C@Cu heterostructure,which buffers the deformation of structure and volume and greatly promotes the cycle life during the potassium/de-potassium process.
查看更多>>摘要：Sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs)have been attracting great attentions and widely been exploited due to the abundant sodium/potas-sium resources.Hence,the preparation of high-powered anode materials for SIBs/PIBs plays a decisive role for the commercial applications of SIBs/PIBs in the future.Man-ganese selenides are a class of potential anode materials for SIBs/PIBs because of their small band gap and high elec-trical conductivity.In this work,MnSe and ReS2 core-shell nanowires connecting by polydopamine derived carbon nanotube(MnSe@NC@ReS2)have been successfully synthesized from growing ReS2 nanosheets array on the surface of MnSe@NC nanowires,which present excellent Na+/K+storage performance.While applied as SIBs anode,the specific capacity of 300 mAh·g-1 was main-tained after 400 cycles at the current density of 1.0 A·g-1.Besides,it could also keep 120 mAh·g-1 specific capacity after 900 cycles at 1.0 A·g-1 for the anode of PIBs.These heterogeneous engineering and one-dimensional-two-di-mensional(1D-2D)hybrid strategies could provide an ideal strategy for the synthesis of new hetero-structured anode materials with outstanding battery performance for SIBs and PIBs.
查看更多>>摘要：Transition metal phosphides hold great potential as sodium-ion batteries anode materials owing to their high theoretical capacity and modest plateau.However,volume changes and low intrinsic conductivity seriously largely hinder the further development of metal phosphide anodes.The design of phosphide anode materials with reasonable structure is conducive to solving the problems of volume expansion and slow reaction kinetics during the reaction.In this work,a composite material integrating zeolite imida-zolate backbone(ZIF)and carbon materials was synthe-sized by the original growth method.Furthermore,by the oxidation-phosphating process,CoP nanoarray composites riveted to carbon fiber(CoP@CF)were obtained.In the CoP@CF,CoP nanoparticles are uniformly distributed on ZIF-derived carbon,reducing agglomeration and volume change during cycling.CF also provides a highly conduc-tive network for the active material,improving the elec-trode kinetics.Therefore,when evaluated as an anode for sodium-ion batteries,CoP@CF electrode displays enhanced reversible capacity(262 mAh·g-1 at 0.1 A·g-1 after 100 cycles),which is much better than that of pure CF electrode(57 mAh·g-1 at 0.1 A·g-1 after 100 cycles)prepared without the addition of CoP.The rate perfor-mance of CoP@CF electrode is also superior to that of pure CF electrode at various current densities from 0.05 to 1 A·g-1.The sodium storage behavior of CoP@CF was revealed by ex-situ X-ray photoelectron spectroscopy,X-ray diffraction,and synchrotron radiation absorption spectroscopy.This method provides a reference for the design and synthesis of anode materials in sodium-ion batteries.
查看更多>>摘要：Metallic zinc is an excellent anode material for Zn-ion batteries,but the growth of Zn dendrite severely hinders its practical application.Herein,an efficient and economical cationic additive,poly dimethyl diallyl ammonium(PDDA)was reported,used in aqueous Zn-ion batteries electrolyte for stabilizing Zn anode.The growth of zinc dendrites can be significantly restrained by bene-fiting from the pronounced electrostatic shielding effect from PDDA on the Zn metal surface.Moreover,the PDDA is preferentially absorbed on Zn(002)plane,thus pre-venting unwanted side reactions on Zn anode.Owing to the introduction of a certain amount of PDDA additive into the common ZnSO4-based electrolyte,the cycle life of assembled Zn||Zn cells(1 mA·cmr-2 and 1 mAh·cm-2)is prolonged to more than 1100 h.In response to the perfo-ration issue of Zn electrodes caused by PDDA additives,the problem can be solved by combining foamy copper with zinc foil.For real application,Zn-ion hybrid super-capacitors and MnO2||Zn cells were assembled,which exhibited excellent cycling stability with PDDA additives.This work provides a new solution and perspective to cope with the dendrite growth problem of Zn anode.
查看更多>>摘要：Composite solid electrolytes(CSEs)containing polymer matrices and inorganic fillers hold promise for the next generation of solid-state batteries.However,the role of residual solvents in CSEs remains controversial.This study investigated the evolution and function of the resid-ual solvent in a polymer-Li2B12H12 CSE.A partial reaction occurred between Li2B12H12 and solvent N,N-dimethyl-formamide(DMF),which produced dimethy-laminomethanol(DMAM)in the CSE.Density functional theory calculations have revealed that DMAM forms stronger hydrogen bonds with polyvinylidene fluoride chains than DMF,which can have a plasticizing effect on the polymer matrix,leading to lower crystallinity and quicker segment motion.Therefore,this CSE exhibited improved Li-ion conducting properties,enabling the stable cycling of Li‖LiFePO4 solid-state batteries.This study provided insights into the role of residual solvents in CSEs.
查看更多>>摘要：In practical applications,relative humidity in the air is a key factor affecting the photocatalytic removal of NO,which is often overlooked in previous studies.Here,we developed a direct Z-scheme UiO-66-NH2/Bi2MoO6 heterojunction with a nanoflower-like structure to system-atically investigate the effect of relative humidity on pho-tocatalytic removal of NO.The optimized heterojunction for the removal efficiency of NO was 71.6％at 1.07 mg.m-3 NO concentration(relative humidity=10％),and the generation of NO2 was only 1.1％.Interestingly,with the increase in relative humidity,it showed a higher inhibition effect on NO2,while the removal of NO decreased slightly(8％),which might be attributed to the affinity effect of NO2 with water molecules and the com-petitive adsorption of H2O and NO on the surface of the heterojunction photocatalysts.Furthermore,the reaction pathways of NO removal at the developed heterojunctions were revealed by in situ DRIFTS analysis.This work provides a novel vision for the development of direct Z-scheme heterojunction photocatalysts to effectively remove NO and inhibit the formation of toxic intermediate NO2 under different humidities.
查看更多>>摘要：To promote charge transfer and separation for efficient photocatalysis,a direct Z-scheme heterostructure was constructed by coupling polymeric carbon nitride(PCN)and WO3.Interestingly,the obtained PCN/WO3 Z-scheme heterostructure could photocatalytically produce hydrogen and value-added chemicals(e.g.,formate and acetate)by reforming of plastic polylactic acid(PLA)in alkaline aqueous condition.By optimizing WO3 contents and reaction conditions,the obtained PCN/WO3 heterostructure exhibits much increased photocatalytic activity for PLA photoreforming under visible light,with hydrogen evolution rate reaching 402.90 pmol·g-1·h-1,which is 3.5 times that of PCN.It is revealed that the Z-scheme charge transfer between PCN and WO3 mainly contributes to the promoted charge separation and thus the improved photocatalytic activity.Moreover,with h+and·OH experimentally evidenced as the predominant active species,a possible reaction pathway for the reforming of PLA into value-added chemicals(e.g.,formate and acetate)over PCN/WO3 Z-scheme heterostructure is cleared by monitoring the reaction intermediates and radicals.This work paves a carbon neutrality and scalable route toward the synergistical production of hydrogen and value-added chemicals by utilizing and recycling plastic waste.
查看更多>>摘要：To solve the problem of high photogenerated carrier recombination rate and low photoelectric conver-sion efficiency of TiO2-based materials,a simple N-doped anatase/rutile TiO2 heterophase nanorod film was designed by a low-temperature hydrothermal method in this work.The enhanced separation and transport of photogenerated charges were facilitated by the smaller contact barrier and appropriate band matching between anatase TiO2 nanoparticles and rutile TiO2 nanorods.The introduction of N doping in anatase TiO2 resulted in an upward shift of the valence band and a narrowing of the band gap,conse-quently enhancing the efficiency of visible light utilization.The combination of the heterophase junction and N-doping exhibited a synergistic effect,effectively suppressing the recombination of photogenerated charges and enhancing the photoelectric conversion efficiency of the photoanode.Under AM 1.5G irradiation,the photocurrent density(J)of the A-TO(N)@R-TONR photoanode reached 2.19 mA·cm-2(VRHE,1.23 eV).Additionally,the incident photon-electron conversion efficiency(IPCE)and the charge injection efficiency(η)reached 81.4％and 51.6％at 320 nm.Furthermore,the J,IPCE,and η values of the A-TO(N)@R-TONR photoanode were 2.96,2.1 and 3.2 times those of pure R-TONR photoanode,respectively.This work presents a rational strategy for designing effi-cient TiO2-based photoanodes.
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