查看更多>>摘要：The appropriate regulation of band structure is an effective strategy in constructing efficient photocatalytic systems.Present photocatalytic system mainly employs powder photocatalysts,which makes their recovery reliant on expensive separation processes and severely limits their industrial application.Herein,we constructed a novel CdS/Ni3S2 heterostructure using free-standing and flexible nickel fiber paper as the matrix.The regulated energy band structure achieves effective electron-hole separation.The as-synthesized flexible photocatalyst exhibits considerable photocatalytic activity toward the H2 evolution reaction under visible-light irradiation,with an H2 production rate of 5.63 μmol·cm-2·h-1(14.1 mmol·g-1cat·h-1 according to the catalyst loading content).Additionally,the otherwise-wasted excited holes simultaneously drive organic trans-formations to yield value-added organic products,thus markedly improving the photocatalytic H2 evolution rate.Such a photocatalytic system is scaled up further,where a self-supported 20 cm × 25 cm sample achieves a cham-pion H2 production rate of 60-80 μmol·h-1 under practical sun irradiation.This newly developed self-supported pho-tocatalyst produces opportunities for practical solar H2 production with biomass upgrading.
查看更多>>摘要：In this study,the truncated octahedral CeO2(CeO2-to)with special morphology was prepared by the solvothermal method with oleic acid(OA)and oleamine(OM)as the morphology-directing agents.High-resolution transmission electron microscopy(HRTEM)results show that CeO2-to exposes composite {100} and {111} facets,while CeO2 cubic(CeO2-c)and CeO2 octahedral(CeO2-o)only expose single crystal facets of {100} plane and {111}plane,respectively.Interestingly,this CeO2-to photocata-lyst exhibits remarkable photooxidation performance of gaseous acetaldehyde(CH3CHO)degradation,in which CO2 generation value reaches 1.78 and 7.97-times greater than that of CeO2-c and CeO2-o,respectively.In addition,the active species trapping experiment signifies that superoxide(·O2-)and holes(h+)are the main reactive substances during the CH3CHO degradation process,and the electron paramagnetic resonance(EPR)spectra indi-cates that the former is the major contributor.Notably,the electron transfer mechanism between CeO2-to {100} and{111} facets and the surface oxygen adsorption ability are revealed via density functional theory(DFT)calculations.It is also confirmed that { 100} facets are more conducive to the absorption of acetaldehyde than { 111} facets.Finally,a reasonable mechanism for improved photocatalytic CH3CHO degradation on CeO2-to is proposed based on relevant experiments and DFT calculations.This study demonstrates that the systematic development of surface homojunction structured photocatalysts can efficiently increase the degradation activity for volatile organic compounds(VOCs).It also offers additional direction for optimizing the photocatalytic activity of other cerium-based photocatalysts.
查看更多>>摘要：Antimony(Sb)is an intriguing anode material for Li-ion batteries(LIBs)owing to its high theoretical capacity of 660 mAh·g-1 and appropriate working poten-tial of～0.8 V(vs.Li+/Li).However,just like all alloying materials,the Sb anode suffers from huge volume expan-sion(230％)during repeated insertion/extraction of Li+ions,resulting in structural deterioration and rapid capacity decay.In this work,a novel amorphous Sb/C composite with atomically dispersed Sb particles in carbon matrix is prepared via a straightforward high-energy ball milling approach.The intimate intermixing of amorphous Sb with C provides homogeneous element distribution and isotropic volume expansion during cycling,resulting in persistent structural stability.Meanwhile,the disordered structure of amorphous material shortens the diffusion distance of lithium ions/electrons,promoting fast reaction kinetics and rate capability.Benefiting from the aforementioned effects,the amorphous Sb/C exhibits a high reversible capacity of 537.4 mAh·g-1 at 0.1 A·g-1 and retains 201.0 mAh·g-1 at an ultrahigh current rate of 10.0 A·g-1.Even after 1500 deep cycles at 2.0 A·g-1,the amorphous Sb/C electrode still maintains 86.3％of its initial capacity,which outper-forms all existing Sb-based anodes reported so far.Post-mortem analysis further reveals a greatly reduced volume variation of merely 34.6％for the amorphous Sb/C elec-trode,much lower than that of 223.1％for crystalline Sb materials.This study presents a new approach to stabilizing Sb-based alloy anodes and contributes to the construction of high-performance amorphous anode materials for LIBs,enabling advanced energy storage.
查看更多>>摘要：Surface modification of graphite anode with electroactive matters has been proven of a more practical strategy in enhancing the performance of Li-ion batteries than exploring alternative novel anode materials.Herein,rutile TiNbO4-x nanoparticles with a tunnel structure are employed as multifunctional decoration substances in combination with a carbon coating layer to improve the rate and cycle properties of mesocarbon microbeads(MCMBs).As compared to pristine MCMB,the Li+diffusion coefficients of the composite anodes are enhanced due to the synergistic effect of TiNbO4-x@C.Meanwhile,the overcharge and voltage polarization of the composite anodes at high rate are obviously minimized due to the current sharing effect of the high-potential TiN-bO4-x.Moreover,the amorphous LiyTiNbO4-x converted from TiNbO4-x in the initial lithiation process can deliver pseudocapacitive capacity to the composite anodes from the second cycle.All of these functions of TiNbO4-x@C coating layer have directly contributed to the improved rate and cycle performance of the MCMB/TiNbO4-x@C composite anodes.The one containing 12.0 wt％TiNbO4-x exhibits a high reversible specific capacity of 118 mAh·g-1 at 10C(1C=372 mA·g-1),together with a high capacity retention of 90.9％after 300 cycles at 3C,which are all much superior to those of pristine MCMB.
查看更多>>摘要：Antimony-based materials with high capacities and moderate potentials are promising anodes for lithium-/-sodium-ion batteries.However,their tremendous volume expansion and inferior conductivity lead to poor structural stability and sluggish reaction kinetics.Herein,a double-confined nanoheterostructure Sb/Sb2S3@Ti3C2Tx@C has been fabricated through a solvothermal method followed by low-temperature heat treatment.The dual protection of"MXene"and"carbon"can better accommodate the volume expansion of Sb/Sb2S3.The strong covalent bond(Ti-S,Ti-O-Sb,C-O-Sb)can firmly integrate Sb-based material with Ti3C2Tx and carbon,which significantly improves the struc-ture stability.In addition,the carbon layer can restrain the oxidation of MXenes,and the nano-Sb/Sb2S3 can facilitate electron/ion transport and suppress the restacking of MXenes.The heterogeneous interface between Sb and Sb2S3 can further promote interfacial charge transfer.The MXene-Sb/Sb2S3@C-1 with the optimal Sb content shows high specific capacities,comparable rate properties and ultra-stable cycling performances(250 mAh·g-1 after 2500 cycles at 1 A·g-1 for sodium-ion batteries).Ex situ X-ray diffractometer(XRD)test reveals the storage mechanism including the conversion and alloying process of MXene-Sb/Sb2S3@C-1.Cyclic voltammetry(CV)test results demonstrate that the pseudo-capacitance behavior is dominant in MXene-Sb/Sb2S3@C-1,especially at large current.This design paves the way for exploring high-performance alloy-based/conversion-type anode for energy storage devices.
查看更多>>摘要：Sb-based materials exhibit considerable poten-tial for sodium-ion storage owing to their high theoretical capacities.However,the bulk properties of Sb-based materials always result in poor cycling and rate perfor-mances.To overcome these issues,pyridine-regulated Sb@InSbS3 ultrafine nanoplates loaded on reduced gra-phene oxides(Sb@InSbS3@rGO)were designed and syn-thesized.During the synthesis process,pyridine was initially adopted to coordinate with In3+,and uniformly dispersed In2S3 ultrafine nanoplates on reduced graphene oxide were generated after sulfidation.Next,partial In3+was exchanged with Sb3+,and Sb@InSbS3@rGO was obtained by using the subsequent annealing method.The unique structure of Sb@InSbS3@rGO effectively short-ened the transfer path of sodium ions and electrons and provided a high pseudocapacitance.As the anode in sodium-ion batteries,the Sb@InSbS3@rGO electrode demonstrated a significantly higher reversible capacity,better stability(445 mAh·g-1 at 0.1 A·g-1 after 200 cycles and 212 mAh·g-1 at 2 A·g-1 after 1200 cycles),and superior rate(210 mAh·g-1 at 6.4 A·g-1)than the elec-trode without pyridine(355 mAh·g-1 at 0.1 A·g-1 after 55 cycles and 109 mAh·g-1 at 2 A·g-1 after 770 cycles).Furthermore,full cells were assembled by using the Sb@InSbS3@rGO as anode and Na3V2(PO4)3 as cathode,which demonstrated good cycling and rate performances and exhibited promising application prospects.These results indicate that adjusting the microstructure of elec-trode materials through coordination balance is A·good strategy for obtaining high-capacity,high-rate,and long-cycle sodium storage performances.
查看更多>>摘要：Mn-based layered oxides are among the most promising cathode materials for sodium-ion batteries owing to the advantages of abundance,environmental friendliness,low cost and high specific capacity.P2 and O'3 are two representative structures of Mn-based layered oxides.However,the P2 structure containing insufficient Na generally exhibits low initial charge capacity,while O'3 structure with sufficient Na delivers high initial charge capacity but poor cycle stability.This study prepared a multitude of NaxMnO2(x=0.7,0.8,0.9)cathode materials with varying P2/O'3 ratios and further investigated their electrochemical performances.The optimized Na0.8MnO2,comprising 69.9 wt％O'3 and 30.1 wt％P2 phase,exhib-ited relatively balanced specific capacity,Coulombic effi-ciency and cycle stability.Specifically,it achieved a high specific capacity of 128.9 mAh·g-1 with an initial Coulombic efficiency of 98.2％in half-cell configuration.The Na0.8MnO2//hard carbon full cell also achieved a high specific capacity of 126.7 mAh·g-1 with an initial Coulombic efficiency of 98.9％.Moreover,the capacity fading mechanism was revealed by combining in-situ and ex-situ X-ray diffraction.The findings of this study provide theoretical guidance for further modification design of Mn-based layered cathodes.
查看更多>>摘要：Sulfur doped carbonaceous materials are promising anodes for potassium-ion batteries because of their ability to bridge active sites and induce C/S electron coupling,resulting in increased ion storage capacitance.However,the large potassium ions could cause significant volume expansion and structure collapse during operation in sulfur doped carbonaceous anodes,which lead to rapidly capacity sacrifice during long-term cycling.Nanopore design for anchoring sulfur atom in carbon skeleton is a novel way to alleviate the structure collapse and maintain the cycling stability.Therefore,this study developed a controlled nanopore and sulfur doped carbon sphere structure(S-NPHCSs).In potassium-ion batteries,S-NPHCSs anode demonstrated exceptional performance with a high reversible capacity of 247 mAh·g-1 after 50 cycles at 0.2 A·g-1 and delivered a long cycle stability of 600 cycles at a high current density of 1.0 A·g-1.Inter-connected nanopores and doped sulfur structure not only expand the accumulation space and offer ample active sites for diffusion and adsorption of potassium ions,but also build stable channels through nanopore structure to ensure the cyclic stability.This finding provides a fundamental theory for designing nanopore structures and introducing sulfur doped carbonaceous materials to enhance capacitive potassium storage and long cycle stability.
查看更多>>摘要：Aqueous zinc-ion batteries have attracted much attention due to their high theoretical capacity,low cost,high safety,and eco-friendly.However,challenges such as dendrite growth and side reactions severely hinder the electrochemical performance of the Zn anode,leading to low Coulombic efficiency(CE)or even short circuits.Herein,phenolic resin(PF)is used as a protective coating on the surface of the zinc metal electrode.The PF layer can greatly improve the corrosion resistance of the Zn electrode in the electrolyte.Importantly,this artificial elec-trode/electrolyte interphase also elevates the nucleation barrier and restrains Zn2+2D diffusion,regulating the zinc deposition/dissolution behavior.As a result,PF@Zn sym-metric cells exhibit superior performance than that of bare Zn symmetric cells,achieving a stable and dendrite-free cycle of 1400 h.Furthermore,the carbon nanotube/MnO2‖PF@Zn(CNT/MnO2‖PF@Zn)full cell also delivers a long cycle life with a high-capacity retention of about 180.0 mAh·g-1 after 1400 cycles,far exceeding that of bare Zn anode.This work provides a facile strategy for achieving a dendrite-free and rechargeable zinc anode.
查看更多>>摘要：Aqueous zinc-ion batteries(AZIBs)are regar-ded as promising energy storage devices due to their low cost,high capacity,and ecological safety.Nevertheless,the severe dendritic growth and side reactions hinder their practical applicability significantly.Herein,an ultrathin Cu coating layer(～200 nm)is decorated on zinc foils via filtered cathodic vacuum arc deposition technology,aiming to achieve high-performance AZIBs.The Cu layer effec-tively suppresses chemical corrosion and hydrogen evolu-tion reactions and enables preferential(002)Zn deposition during the stripping/plating cycles.Consequently,the Cu@Zn anode represents an elongated cycle life over 4,000 h at 2 mA·cm-2/2 mAh·cm-2.Even in conditions of high current density of 5 and 10 mA·cm-2,the Cu@Zn anode shows prolonged cycling stability exceeding 4000 and 2000 h,respectively.Such advantages also bring high Coulombic efficiency of 99.87％under 5 mAh·cm-2 in Cu@Ti‖Zn half-cell over 1500 cycles.Moreover,the Cu@Zn‖MnO2 full cell demonstrates a superior cyclability with a specific capacity of 203 mAh·g-1 after 500 cycles at 1 A·g-1.
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