The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-...The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.展开更多
The intrinsic clustering behavior and kinetically sluggish conversion process of lithium polysulfides seriously limit the electrochemical reversibility of sulfur redox reactions in lithium-sulfur(Li-S)batteries.Here,w...The intrinsic clustering behavior and kinetically sluggish conversion process of lithium polysulfides seriously limit the electrochemical reversibility of sulfur redox reactions in lithium-sulfur(Li-S)batteries.Here,we introduce molybdenum pentachloride(MoCl_(5))into the electrolyte which could coordinate with lithium polysulfides and inhibit their intrinsic clustering behavior,subsequently serving as an improved mediator with the bi-functional catalytic effect for Li_(2)S deposition and activation.Moreover,the coordination bonding and accelerated conversion reaction can also greatly suppress the dissolution and shuttling of polysulfides.Consequently,such polysulfide complexes enable the Li-S coin cell to exhibit good longterm cycling stability with a capacity decay of 0.078%per cycle after 400 cycles at 2 C,and excellent rate performance with a discharge capacity of 589 mAh/g at 4 C.An area capacity of 3.94 mAh/cm^(2)is also achieved with a high sulfur loading of 4.5mg/cm^(2)at 0.2 C.Even at-20℃,the modified cell maintains standard discharge plateaus with low overpotential,delivering a high capacity of 741 mAh/g at 0.2 C after 80 cycles.The low-cost and convenient MoCl_(5)additive opens a new avenue for the effective regulation of polysulfides and significant enhancement in sulfur redox conversion.展开更多
Natural hydraulic lime(NHL) has garnered increasing attention for its sustainable and suitable performance in the field of historical building restoration. However, the prolonged hardening time and sluggish hydration ...Natural hydraulic lime(NHL) has garnered increasing attention for its sustainable and suitable performance in the field of historical building restoration. However, the prolonged hardening time and sluggish hydration rate of NHL infiuence the workability, strength development, and durability of construction structures in which it is used. In this study, nano-metakaolin(NMK) was applied as a highly reactive supplementary cementitious material(SCM) for NHL-based mortars to enhance their properties with various ratios. Meanwhile, the effects of NMK and its related enhancement mechanism on the physical properties and chemical structures of NHL composites were systematically investigated, mainly involving the modifications in their microstructure, chemical composition, and C-S-H structure. Results demonstrated that NMK-modified samples showed distinct and superior properties to pure NHL sample, such as shorter initial/final setting times(15.1%–49.1%, 27.1%–50.0%), and higher compactness(67.8%–81.4%, 38.1%–44.8%),lower shrinkage(25.0%–56.3%, 12.5%–25.0%), enhanced compressive strength(404.5%–546.0%, 180.8%–354.1%) and fiexural strength(227.5%–351.1%, 59.9%–125.7%) for both early and late curing times(7 and28 days). The inclusion of NMK not only acts as a fine filler, but also promotes NHL's hydrate rate by its super high pozzolanic activity, thus optimizing the pore structures and increasing the content and the average silicate chain length of hydration gel in NHL. Overall, this study can contribute to a deeper understanding of the enhancement mechanism of NMK on the physical properties and chemical structures of NHL from a meso/microscopic perspective, with a view to broadening NHL's potential applications.展开更多
ZnO with good lithiophilicity has widely been employed to modify the lithiophobic substrates and facilitate uniform lithium(Li)deposition.The overpotential of ZnO-derived Li anode during cycling depends on the lithiop...ZnO with good lithiophilicity has widely been employed to modify the lithiophobic substrates and facilitate uniform lithium(Li)deposition.The overpotential of ZnO-derived Li anode during cycling depends on the lithiophilicity of both LiZn and Li_(2)O products upon lithiation of ZnO.However,the striking differences in the lithiophilicity between Li_(2)O and LiZn would result in a high overpotential during cycling.In this research,the Al_(2)O_(3)/nZnO(n≥1)hybrid layers were precisely fabricated by atomic layer deposition(ALD)to regulate the lithiophilicity of ZnO phase and Li_(2)O/LiZn configuration—determining the actual Li loading amount and Li plating/stripping processes.Theoretically,the Li adsorption energy(E_(a))values of LiZn and Li_(2)O in the LiZn/Li_(2)O configuration are separately predicted as-2.789 and-3.447 eV.In comparison,the E_(a) values of LiZn,LiAlO_(2),and Li_(2)O in the LiZn/LiAlO_(2)/Li_(2)O configuration upon lithiation of Al_(2)O_(3)/8ZnO layer are calculated as-2.899,-3.089,and-3.208 eV,respectively.Importantly,a novel introduction of LiAlO_(2)into the LiZn/Li_(2)O configuration could enable the hierarchical Li plating/stripping and reduce the overpotentials during cycling.Consequently,the Al_(2)O_(3)/8ZnO-derived hybrid Li-metal anode could exhibit electrochemical performances superior to these of ZnO-derived Li anode in both symmetrical and full cells paired with a LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cathode.展开更多
Realizing the high thermoelectric performance of p-type AgBiSe_(2)-based materials has been challenging due to their low p-type dopability.This work demonstrated that Cd doping at the Bi site converts n-type AgBiSe_(2...Realizing the high thermoelectric performance of p-type AgBiSe_(2)-based materials has been challenging due to their low p-type dopability.This work demonstrated that Cd doping at the Bi site converts n-type AgBiSe_(2) to p-type.The hole concentration is effectively increased with increasing Cd doping content,thereby enhancing the electrical conductivity.Theoretical calculations reveal that Cd doping flattens the edge of the valence band,resulting in an increase in the density-of-states effective mass and Seebeck coefficient.A record-high power factor of~6.2µW·cm^(−1)·K^(−2) was achieved at room temperature.Furthermore,the induced dislocations enhance the phonon scattering,contributing to the ultralow lattice thermal conductivity across the entire temperature range.As a result,a decent figure of merit(zT)of~0.3 at room temperature and a peak zT of~0.5 at 443 K were obtained in AgBi0.92Cd0.08Se_(2).Our work provides a feasible method for optimizing the thermoelectric performance of p-type AgBiSe_(2).展开更多
Lithium-sulfur batteries(LSBs)have already developed into one of the most promising new-generation high-energy density electrochemical energy storage systems with outstanding features including high-energy density,low...Lithium-sulfur batteries(LSBs)have already developed into one of the most promising new-generation high-energy density electrochemical energy storage systems with outstanding features including high-energy density,low cost,and environmental friendliness.However,the development and commercialization path of LSBs still presents significant limitations and challenges,particularly the notorious shuttle effect triggered by soluble longchain lithium polysulfides(LiPSs),which inevitably leads to low utilization of cathode active sulfur and high battery capacity degradation,short cycle life,etc.Substantial research efforts have been conducted to develop various sulfur host materials capable of effectively restricting the shuttle effect.This review firstly introduces the fundamental electrochemical aspects of LSBs,followed by a comprehensive analysis of the mechanism underlying the shuttle effect in Li–S batteries and its profound influence on various battery components as well as the overall battery performance.Subsequently,recent advances and strategies are systematically reviewed,including physical confinement,chemisorption,and catalytic conversion of sulfur hosts for restricting LiPSs shuttle effects.The interplay mechanisms of sulfur hosts and LiPSs are discussed in detail and the structural advantages of different host materials are highlighted.Furthermore,key insights for the rational design of advanced host materials for LSBs are provided,and the upcoming challenges and the prospects for sulfur host materials in lithium-sulfur batteries are also explored.展开更多
Joint time–frequency analysis is an emerging method for interpreting the underlying physics in fuel cells,batteries,and supercapacitors.To increase the reliability of time–frequency analysis,a theoretical correlatio...Joint time–frequency analysis is an emerging method for interpreting the underlying physics in fuel cells,batteries,and supercapacitors.To increase the reliability of time–frequency analysis,a theoretical correlation between frequency-domain stationary analysis and time-domain transient analysis is urgently required.The present work formularizes a thorough model reduction of fractional impedance spectra for electrochemical energy devices involving not only the model reduction from fractional-order models to integer-order models and from high-to low-order RC circuits but also insight into the evolution of the characteristic time constants during the whole reduction process.The following work has been carried out:(i)the model-reduction theory is addressed for typical Warburg elements and RC circuits based on the continued fraction expansion theory and the response error minimization technique,respectively;(ii)the order effect on the model reduction of typical Warburg elements is quantitatively evaluated by time–frequency analysis;(iii)the results of time–frequency analysis are confirmed to be useful to determine the reduction order in terms of the kinetic information needed to be captured;and(iv)the results of time–frequency analysis are validated for the model reduction of fractional impedance spectra for lithium-ion batteries,supercapacitors,and solid oxide fuel cells.In turn,the numerical validation has demonstrated the powerful function of the joint time–frequency analysis.The thorough model reduction of fractional impedance spectra addressed in the present work not only clarifies the relationship between time-domain transient analysis and frequency-domain stationary analysis but also enhances the reliability of the joint time–frequency analysis for electrochemical energy devices.展开更多
Hexagonal boron nitride nanosheets(BNNSs)exhibit remarkable thermal and dielectric properties.However,their self-assembly and alignment in macroscopic forms remain challenging due to the chemical inertness of boron ni...Hexagonal boron nitride nanosheets(BNNSs)exhibit remarkable thermal and dielectric properties.However,their self-assembly and alignment in macroscopic forms remain challenging due to the chemical inertness of boron nitride,thereby limiting their performance in applications such as thermal management.In this study,we present a coaxial wet spinning approach for the fabrication of BNNSs/polymer composite fibers with high nanosheet orientation.The composite fibers were prepared using a superacid-based solvent system and showed a layered structure comprising an aramid core and an aramid/BNNSs sheath.Notably,the coaxial fibers exhibited significantly higher BNNSs alignment compared to uniaxial aramid/BNNSs fibers,primarily due to the additional compressive forces exerted at the core-sheath interface during the hot drawing process.With a BNNSs loading of 60 wt%,the resulting coaxial fibers showed exceptional properties,including an ultrahigh Herman orientation parameter of 0.81,thermal conductivity of 17.2 W m^(-1)K^(-1),and tensile strength of 192.5 MPa.These results surpassed those of uniaxial fibers and previously reported BNNSs composite fibers,making them highly suitable for applications such as wearable thermal management textiles.Our findings present a promising strategy for fabricating high-performance composite fibers based on BNNSs.展开更多
Calcium-ion batteries have been considered attractive candidates for large-scale energy storage applications due to their natural abundance and low redox potential of Ca^(2+)/Ca.However,current calcium ion technology ...Calcium-ion batteries have been considered attractive candidates for large-scale energy storage applications due to their natural abundance and low redox potential of Ca^(2+)/Ca.However,current calcium ion technology is still hampered by the lack of high-capacity and long-life electrode materials to accommodate the large Ca^(2+)(1.00Å).Herein,an amorphous vanadium structure induced by Mo doping and in-situ electrochemical activation is reported as a high-rate anode material for calcium ion batteries.The doping of Mo could destroy the lattice stability of VS4 material,enhancing the flexibility of the structure.The following electrochemical activation further converted the material into sulfide and oxides co-dominated composite(defined as MoVSO),which serves as an active material for the storage of Ca^(2+)during cycling.Consequently,this amorphous vanadium structure exhibits excellent rate capability,achieving discharge capacities of 306.7 and 149.2 mAh g^(-1)at 5 and 50 A g^(-1)and an ultra-long cycle life of 2000 cycles with 91.2%capacity retention.These values represent the highest level to date reported for calcium ion batteries.The mechanism studies show that the material undergoes a partial phase transition process to derive MoVSO.This work unveiled the calcium storage mechanism of vanadium sulfide in aqueous electrolytes and accelerated the development of high-performance aqueous calcium ion batteries.展开更多
N-doped carbon materials,with their applications as electrocatalysts for the oxygen reduction reaction(ORR),have been extensively studied.However,a negletcted fact is that the operating potential of the ORR is higher ...N-doped carbon materials,with their applications as electrocatalysts for the oxygen reduction reaction(ORR),have been extensively studied.However,a negletcted fact is that the operating potential of the ORR is higher than the theoretical oxida-tion potential of carbon,possibly leading to the oxidation of carbon materials.Consequently,the infl uence of the structural oxidation evolution on ORR performance and the real active sites are not clear.In this study,we discover a two-step oxida-tion process of N-doped carbon during the ORR.The fi rst oxidation process is caused by the applied potential and bubbling oxygen during the ORR,leading to the oxidative dissolution of N and the formation of abundant oxygen-containing functional groups.This oxidation process also converts the reaction path from the four-electron(4e)ORR to the two-electron(2e)ORR.Subsequently,the enhanced 2e ORR generates oxidative H_(2)O_(2),which initiates the second stage of oxidation to some newly formed oxygen-containing functional groups,such as quinones to dicarboxyls,further diversifying the oxygen-containing functional groups and making carboxyl groups as the dominant species.We also reveal the synergistic eff ect of multiple oxygen-containing functional groups by providing additional opportunities to access active sites with optimized adsorption of OOH*,thus leading to high effi ciency and durability in electrocatalytic H_(2)O_(2) production.展开更多
Tannin was extracted from different subspecies of Acacia nilotica,Acacia nilotica nilotica(Ann),Acacia nilotica tomentosa(Ant)and Acacia nilotica adansonii(Ana).The aim was to elucidate their structure and evaluate th...Tannin was extracted from different subspecies of Acacia nilotica,Acacia nilotica nilotica(Ann),Acacia nilotica tomentosa(Ant)and Acacia nilotica adansonii(Ana).The aim was to elucidate their structure and evaluate their reactivity as bioadhesives in the wood industry.The extracts were prepared by hot water extraction(90°C tem-perature).Their gel time with paraformaldehyde was used atfirst to compare their reactivity.The tannin contents and the percentage of total polyphenolic materials in different solutions of the extracts spray dried powder were determined by the hide powder method.Concentrated solutions(47%)were tested by both MALDI ToF,13CNMR.The thermomechanical analysis(TMA)was performed to evaluate their modulus of elasticity(MOE)at different pHs.The gel times of all the three tannin extracts showed that their reactivity and it was com-parable to other known procyanidin/prodelphinidin tannin extract types.Ana,Ann and Ant showed highest per-cent of total polyphenolic materials at 70%,64%,and 57%,respectively.The 13CNMR spectra showed that the three subspecies of condensed tannins were mainly constituted of procyanidins(PC)and prodelphinidins(PD)in slightly different ratios.Ann(56.5%PC and 43.4%PD),Ant(57%PC and 43%PD)and Ana(58%PC and 42%PD).MALDI–TOF spectra showed the presence offlavonoid monomers,and oligomers some of which linked to short carbohydrates monomers or dimers.TMA revealed that the three types of tannins had high MOE at their initial pH(5).展开更多
Electrochemical nitrate reduction to NH_(3)holds a great promise for N-upcycling in nature,while its sluggish reaction kinetics involved in both the stepwise deoxygenation and hydrogenation processes necessitates the ...Electrochemical nitrate reduction to NH_(3)holds a great promise for N-upcycling in nature,while its sluggish reaction kinetics involved in both the stepwise deoxygenation and hydrogenation processes necessitates the development of bespoke catalysts with multi-site engineering.Herein,we report a hybrid catalyst composed of rare-earth(RE)yttrium(Y)single atoms and copper phosphide(Cu_(3)P)nanoparticles loaded on N,P-doped carbon(Y_(SA)-Cu_(3)P/CNP)through a chelating and pyrolysis method.Owing to a synergistic contribution of Y single atoms and Cu_(3)P nanoparticles,Y_(SA)-Cu_(3)P/CNP achieves an impressive NH_(3)Faradaic efficiency(FE)of 92%at-0.5V(vs.RHE)and the highest NH_(3)yield rate of11.4 mg·h^(-1)·cm^(-2)at-0.6 V(vs.RHE)in an alkaline media,which surpass most of the reported electrocatalysts.The intricate reaction pathway has been explored by online differential electrochemical mass spectrometry(DEMS),and the synergistic effect between Y single atoms and Cu_(3)P nanoparticles has been studied by in situ synchrotron X-ray absorption spectroscopy.Moreover,density-functional theory(DFT)calculations unveil that the high-efficiency nitrate reduction on Y_(SA)-Cu_(3)P/CNP is attributed to a reduced energy barrier of the rate-determining deoxygenation step coupled with the enhanced stabilization of active hydrogen favorable for the hydrogenation steps,thereby boosting the overall reaction rates.In addition,a prototype Zn-nitrate battery utilizing Y_(SA)-Cu_(3)P/CNP as the cathode is unveiled.This work not only elucidates the mechanism behind the enhanced catalytic performance but also paves the way for the future development of highefficiency electrocatalysts through dual-site engineering.展开更多
Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(gen...Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(generally 5%–10%)during Li^(+)storage causes unsatisfactory long-term cyclability.Here,“zero-strain”NiNb_(2)O_(6) fibers are explored as a new anode material with comprehensively good electrochemical properties.During Li^(+)storage,the expansion of electrochemical inactive NiO_(6) octahedra almost fully offsets the shrinkage of active NbO_(6) octahedra through reversible O movement.Such superior volume-accommodation capability of the NiO_(6) layers guarantees the“zero-strain”behavior of NiNb_(2)O_(6) in a broad temperature range(0.53%//0.51%//0.74%at 25//−10//60℃),leading to the excellent cyclability of the NiNb_(2)O_(6) fibers(92.8%//99.2%//91.1%capacity retention after 1000//2000//1000 cycles at 10C and 25//−10//60℃).This NiNb_(2)O_(6) material further exhibits a large reversible capacity(300//184//318 mAh g−1 at 0.1C and 25//−10//60℃)and outstanding rate performance(10 to 0.5C capacity percentage of 64.3%//50.0%//65.4%at 25//−10//60℃).Therefore,the NiNb_(2)O_(6) fibers are especially suitable for large-capacity,fast-charging,long-life,and all-climate lithium-ion batteries.展开更多
The electrolysis of alkaline seawater is critical for sustainable hydrogen production but is hindered by the sluggish oxygen evolution reaction in saline environments.Advanced electrocatalysts with tailored structures...The electrolysis of alkaline seawater is critical for sustainable hydrogen production but is hindered by the sluggish oxygen evolution reaction in saline environments.Advanced electrocatalysts with tailored structures and electronic properties are essential,and phase engineering provides a transformative approach by modulating crystallographic symmetry and electronic configurations.Two-dimensional(2D)LaMnO_(3) perovskites show promise due to their exposed active sites and tunable electronic properties.However,the conventional stable rhombohedral phase limits oxygen diffusion despite good electron transport.Unconventional metastable phases with superior symmetry enhance lattice oxygen activity in saline environments but are challenging to synthesize.Herein,we propose a microwave shock method incorporating Co atoms to rapidly produce 2D LaMnO_(3) in rhombohedral,hexagonal,and metastable cubic phases.This strategy circumvents the limitations of high-temperature synthesis,preserving the 2D morphology while enabling the formation of metastable cubic phases.The metastable cubic phase exhibits superior OER activity and stability even in alkaline seawater due to optimal symmetry,interlayer spacing,and Mn-O covalency.X-ray absorption spectroscopy and theoretical calculations further highlight its balanced oxygen adsorption and desorption.This work underscores the role of metastable phase engineering in advancing seawater electrolysis and establishes a scalable route for designing high-performance 2D electrocatalysts.展开更多
Designing advanced electrocatalysts with high methanol tolerance in the oxygen reduction reaction process is crucial for the sustainable implementation of direct methanol fuel cells.Herein,we present a Pt/C catalyst m...Designing advanced electrocatalysts with high methanol tolerance in the oxygen reduction reaction process is crucial for the sustainable implementation of direct methanol fuel cells.Herein,we present a Pt/C catalyst modified with black phosphorus(BP)nanodots(BPNDs-Pt/C)by using a facile ultrasonic mixing method.Experimental and computational investigations reveal that the electron transfer from BP to Pt leads to weak adsorption of hydroxyl groups on the Pt surface.As a result,the BPNDs-Pt/C catalyst exhibits efficient activity and anti-methanol ability for cathodic oxygen reduction electrocatalysis in an acidic medium.Additionally,it demonstrates high activity for oxygen reduction reaction(ORR)in an alternative alkaline system with cation exchange membrane and eliminable methanol penetration.This work highlights the feasibility of using non-metallic elements to regulate the electronic structure and surface properties of Pt-based nanomaterials.Furthermore,the designed BPNDs-Pt/C electrocatalyst,with controllable ORR performance,can be applied across various scenarios based on demand.展开更多
Widely used spin-coated nickle oxide (NiOx) based perovskite solar cells often suffer from severe interfacial reactions between the NiOxand adjacent perovskite layers due to surface defect states,which inherently impa...Widely used spin-coated nickle oxide (NiOx) based perovskite solar cells often suffer from severe interfacial reactions between the NiOxand adjacent perovskite layers due to surface defect states,which inherently impair device performance in a long-term view,even with surface molecule passivation.In this study,we developed high-quality magnetron-sputtered NiOxthin films through detailed process optimization,and compared systematically sputtered and spin-coated NiOxthin film surfaces from materials to devices.These sputtered NiOxfilms exhibit improved crystallinity,smoother surfaces,and significantly reduced Ni3+or Ni vacancies compared to their spin-coated counterparts.Consequently,the interface between the perovskite and sputtered NiOxfilm shows a substantially reduced density of defect states.Perovskite solar cells (PSCs) fabricated with our optimally sputtered NiOxfilms achieved a high power conversion efficiency (PCE) of up to 19.93%and demonstrated enhanced stability,maintaining 86.2% efficiency during 500 h of maximum power point tracking under one standard sun illumination.Moreover,with the surface modification using (4-(2,7-dibromo-9,9-dimethylacridin-10(9H)-yl)butyl)p hosphonic acid (DMAcPA),the device PCE was further promoted to 23.07%,which is the highest value reported for sputtered NiOxbased PSCs so far.展开更多
Glioma is the most common malignant tumor of the brain. The postoperative recurrence rate was high,and the 2-year survival rate only increased by 20%–25%. The reason is the blood-brain barrier(BBB). BBB is a physical...Glioma is the most common malignant tumor of the brain. The postoperative recurrence rate was high,and the 2-year survival rate only increased by 20%–25%. The reason is the blood-brain barrier(BBB). BBB is a physical barrier that stabilizes the physiological environment of brain tissue and protects the central nervous system from the invasion of harmful substances. Drug delivery based on nanotechnology and nanocarriers has attracted much attention due to its biological safety, continuous drug release time,increasing solubility, biological drug activity, and enhanced BBB permeability. By modifying different substances on the surface of nanocarriers, the BBB is bypassed by receptor-mediated and cell endocytosis and exocytosis. In addition, the purpose of bypassing BBB-targeted drug delivery can also be achieved by intranasal administration and local administration. This paper reviews different target transport mechanisms, mainly in invasive and non-invasive strategies, the nanocarriers that have made progress and the nanocarrier strategy of bypassing BBB are listed.展开更多
Single-metal sites anchored in nitrogen-doped nanocarbons are recognized as potent electrocatalysts for applications in energy conversion and storage.Here,an innovative inorganic salt-mediated secondary calcination st...Single-metal sites anchored in nitrogen-doped nanocarbons are recognized as potent electrocatalysts for applications in energy conversion and storage.Here,an innovative inorganic salt-mediated secondary calcination strategy was developed to construct robust Pt single-atom catalysts on nitrogen-and oxygen-doped graphene nanosheets(Pt-N/O-GNs),thereby significantly enhancing the efficiency of the electrocatalytic oxygen reduction reaction(ORR).The ultrathin N/O-GNs,obtained by stripping Zn-ZIF with auxiliaries of KCl and LiCl,provide stable anchoring sites for highly exposed Pt-N_(3)O active structures.The Pt-N/O-GNs catalyst,featuring a low Pt loading of 0.44 wt%,demonstrates exceptional mass activity in the ORR process.It attains an impressive onset potential of 0.99 V and a half-wave potential of 0.88 V.The zinc-air battery driven by the Pt-N/O-GNs displays superior power density and cycle stability.Theoretical computational studies reveal that the structure of heteroatoms doped in few-layer graphene facilitates the stable anchoring of single-atom configurations.The findings provide new perspectives for the tailored design and fabrication of single-metal-site electrocatalysts.展开更多
Single-walled carbon nanotubes(SWNTs)with enriched(n,m)species are in high demand for various advanced applications.Since the SWNT structure is largely influenced by the chemistry of the active catalyst during growth ...Single-walled carbon nanotubes(SWNTs)with enriched(n,m)species are in high demand for various advanced applications.Since the SWNT structure is largely influenced by the chemistry of the active catalyst during growth process,exploiting novel catalyst with bias towards specific SWNT chiralities has been challenging.In this work,we introduce a vanadium catalyst supported by mesoporous magnesia(V-MgO)for the selective growth of SWNTs using CO chemical vapor deposition(CVD).At a reaction temperature of 650℃,the(6,5)SWNT content reaches an impressive 67.9%among all semiconducting species,exceeding the selectivity of many commercial SWNT products.Post-CVD analysis reveals that the catalyst transforms into vanadium carbide(VC),which acts as a nucleation site for SWNT growth.Molecular dynamics simulations indicate that the energy at the SWNT-VC interface and the growth kinetics of SWNTs contribute to the chirality selectivity.This research opens up possibilities for the selective synthesis of SWNTs using cost-effective early transition metals,illuminating their future applications in fields such as bioimaging.展开更多
Li metal is widely recognized as the desired anode for next-generation energy storage,Li metal batteries,due to its highest theoretical capacity and lowest potential.Nonetheless,it suffers from unstable electrochemica...Li metal is widely recognized as the desired anode for next-generation energy storage,Li metal batteries,due to its highest theoretical capacity and lowest potential.Nonetheless,it suffers from unstable electrochemical behaviors like dendrite growth and side reactions in practical application.Herein,we report a highly stable anode with collector,Li_(5)Mg@Cu,realized by the melting-rolling process.The Li_(5)Mg@Cu anode delivers ultrahigh cycle stability for 2000 and 1000 h at the current densities of 1 and 2 mA cm^(-2),respectively in symmetric cells.Meanwhile,the Li_(5)Mg@Cu|LFP cell exhibits a high-capacity retention of 91.8% for 1000 cycles and 78.8% for 2000 cycles at 1 C.Moreover,we investigate the suppression effects of Mg on the dendrite growth by studying the performance of Li_(x)Mg@Cu electrodes with different Mg contents(2.0-16.7 at%).The exchange current density,surface energy,Li^(+)diffusion coefficient,and chemical stability of Li_(x)Mg@Cu concretely reveal this improving suppression effect when Mg content becomes higher.In addition,a Mg-rich phase with“hollow brick”morphology forming in the high Mg content Li_(x)Mg@Cu guides the uniform deposition of Li.This study reveals the suppression effects of Mg on Li dendrites growth and offers a perspective for finding the optimal component of Li-Mg alloys.展开更多
基金sponsored by the National Natural Science Foundation of China(Nos.5210125 and 52375422)the Science Research Project of Hebei Education Department(No.BJK2023058)the Natural Science Foundation of Hebei Province(Nos.E2020208069,B2020208083 and E202320801).
文摘The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.
基金the National Natural Science Foundation of China(Nos.51904344,52172264)the Natural Science Foundation of Hunan Province of China(Nos.2021JJ10060 and 2022GK2033).
文摘The intrinsic clustering behavior and kinetically sluggish conversion process of lithium polysulfides seriously limit the electrochemical reversibility of sulfur redox reactions in lithium-sulfur(Li-S)batteries.Here,we introduce molybdenum pentachloride(MoCl_(5))into the electrolyte which could coordinate with lithium polysulfides and inhibit their intrinsic clustering behavior,subsequently serving as an improved mediator with the bi-functional catalytic effect for Li_(2)S deposition and activation.Moreover,the coordination bonding and accelerated conversion reaction can also greatly suppress the dissolution and shuttling of polysulfides.Consequently,such polysulfide complexes enable the Li-S coin cell to exhibit good longterm cycling stability with a capacity decay of 0.078%per cycle after 400 cycles at 2 C,and excellent rate performance with a discharge capacity of 589 mAh/g at 4 C.An area capacity of 3.94 mAh/cm^(2)is also achieved with a high sulfur loading of 4.5mg/cm^(2)at 0.2 C.Even at-20℃,the modified cell maintains standard discharge plateaus with low overpotential,delivering a high capacity of 741 mAh/g at 0.2 C after 80 cycles.The low-cost and convenient MoCl_(5)additive opens a new avenue for the effective regulation of polysulfides and significant enhancement in sulfur redox conversion.
基金sponsored by National Key R&D Program of China (No. 2021YFC1523403)Guangxi Key Technologies R&D Program (No. AB22080102)+1 种基金Shanxi Provincial Cultural Relics Protection Science and Technology Program (No. 208141400241)Special Key Project of Chongqing Technology Innovation and Application Development (No. CSTB2022TIAD-KPX0095)。
文摘Natural hydraulic lime(NHL) has garnered increasing attention for its sustainable and suitable performance in the field of historical building restoration. However, the prolonged hardening time and sluggish hydration rate of NHL infiuence the workability, strength development, and durability of construction structures in which it is used. In this study, nano-metakaolin(NMK) was applied as a highly reactive supplementary cementitious material(SCM) for NHL-based mortars to enhance their properties with various ratios. Meanwhile, the effects of NMK and its related enhancement mechanism on the physical properties and chemical structures of NHL composites were systematically investigated, mainly involving the modifications in their microstructure, chemical composition, and C-S-H structure. Results demonstrated that NMK-modified samples showed distinct and superior properties to pure NHL sample, such as shorter initial/final setting times(15.1%–49.1%, 27.1%–50.0%), and higher compactness(67.8%–81.4%, 38.1%–44.8%),lower shrinkage(25.0%–56.3%, 12.5%–25.0%), enhanced compressive strength(404.5%–546.0%, 180.8%–354.1%) and fiexural strength(227.5%–351.1%, 59.9%–125.7%) for both early and late curing times(7 and28 days). The inclusion of NMK not only acts as a fine filler, but also promotes NHL's hydrate rate by its super high pozzolanic activity, thus optimizing the pore structures and increasing the content and the average silicate chain length of hydration gel in NHL. Overall, this study can contribute to a deeper understanding of the enhancement mechanism of NMK on the physical properties and chemical structures of NHL from a meso/microscopic perspective, with a view to broadening NHL's potential applications.
基金supported by the National Key Research and Development Program of China(2021YFB2400202)the National Natural Science Foundation of China(52104313)+1 种基金the Key Research and Development Plan of Shaanxi(2024GH-YBXM-11)the Foshan Science and Technology Innovation Team Project(1920001004098).
文摘ZnO with good lithiophilicity has widely been employed to modify the lithiophobic substrates and facilitate uniform lithium(Li)deposition.The overpotential of ZnO-derived Li anode during cycling depends on the lithiophilicity of both LiZn and Li_(2)O products upon lithiation of ZnO.However,the striking differences in the lithiophilicity between Li_(2)O and LiZn would result in a high overpotential during cycling.In this research,the Al_(2)O_(3)/nZnO(n≥1)hybrid layers were precisely fabricated by atomic layer deposition(ALD)to regulate the lithiophilicity of ZnO phase and Li_(2)O/LiZn configuration—determining the actual Li loading amount and Li plating/stripping processes.Theoretically,the Li adsorption energy(E_(a))values of LiZn and Li_(2)O in the LiZn/Li_(2)O configuration are separately predicted as-2.789 and-3.447 eV.In comparison,the E_(a) values of LiZn,LiAlO_(2),and Li_(2)O in the LiZn/LiAlO_(2)/Li_(2)O configuration upon lithiation of Al_(2)O_(3)/8ZnO layer are calculated as-2.899,-3.089,and-3.208 eV,respectively.Importantly,a novel introduction of LiAlO_(2)into the LiZn/Li_(2)O configuration could enable the hierarchical Li plating/stripping and reduce the overpotentials during cycling.Consequently,the Al_(2)O_(3)/8ZnO-derived hybrid Li-metal anode could exhibit electrochemical performances superior to these of ZnO-derived Li anode in both symmetrical and full cells paired with a LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cathode.
基金supported by the Fundamental Research Funds for the Central Universities(No.G2022WD01007)the Natural Science Foundation of Shaanxi Province(No.2023-JC-QN-0380)+2 种基金Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515111200 and 2021A1515111155)Nantong Natural Science Foundation(No.JC2023080)the Basic Research Programs of Taicang(Nos.TC2022JC08 and TC2023JC03).
文摘Realizing the high thermoelectric performance of p-type AgBiSe_(2)-based materials has been challenging due to their low p-type dopability.This work demonstrated that Cd doping at the Bi site converts n-type AgBiSe_(2) to p-type.The hole concentration is effectively increased with increasing Cd doping content,thereby enhancing the electrical conductivity.Theoretical calculations reveal that Cd doping flattens the edge of the valence band,resulting in an increase in the density-of-states effective mass and Seebeck coefficient.A record-high power factor of~6.2µW·cm^(−1)·K^(−2) was achieved at room temperature.Furthermore,the induced dislocations enhance the phonon scattering,contributing to the ultralow lattice thermal conductivity across the entire temperature range.As a result,a decent figure of merit(zT)of~0.3 at room temperature and a peak zT of~0.5 at 443 K were obtained in AgBi0.92Cd0.08Se_(2).Our work provides a feasible method for optimizing the thermoelectric performance of p-type AgBiSe_(2).
基金supported by the National Natural Science Foundation of China(Nos.52105575&52205593)the Fundamental Research Funds for the Central Universities(No.QTZX23063)+1 种基金the Proof of Concept Foundation of Xidian University Hangzhou Institute of Technology(Nos.GNYZ2023YL0302&GNYZ2023QC0401)the Aeronautical Science Foundation of China(No.2022Z073081001)。
文摘Lithium-sulfur batteries(LSBs)have already developed into one of the most promising new-generation high-energy density electrochemical energy storage systems with outstanding features including high-energy density,low cost,and environmental friendliness.However,the development and commercialization path of LSBs still presents significant limitations and challenges,particularly the notorious shuttle effect triggered by soluble longchain lithium polysulfides(LiPSs),which inevitably leads to low utilization of cathode active sulfur and high battery capacity degradation,short cycle life,etc.Substantial research efforts have been conducted to develop various sulfur host materials capable of effectively restricting the shuttle effect.This review firstly introduces the fundamental electrochemical aspects of LSBs,followed by a comprehensive analysis of the mechanism underlying the shuttle effect in Li–S batteries and its profound influence on various battery components as well as the overall battery performance.Subsequently,recent advances and strategies are systematically reviewed,including physical confinement,chemisorption,and catalytic conversion of sulfur hosts for restricting LiPSs shuttle effects.The interplay mechanisms of sulfur hosts and LiPSs are discussed in detail and the structural advantages of different host materials are highlighted.Furthermore,key insights for the rational design of advanced host materials for LSBs are provided,and the upcoming challenges and the prospects for sulfur host materials in lithium-sulfur batteries are also explored.
基金support from the National Science Foundation of China(22078190)the National Key R&D Plan of China(2020YFB1505802).
文摘Joint time–frequency analysis is an emerging method for interpreting the underlying physics in fuel cells,batteries,and supercapacitors.To increase the reliability of time–frequency analysis,a theoretical correlation between frequency-domain stationary analysis and time-domain transient analysis is urgently required.The present work formularizes a thorough model reduction of fractional impedance spectra for electrochemical energy devices involving not only the model reduction from fractional-order models to integer-order models and from high-to low-order RC circuits but also insight into the evolution of the characteristic time constants during the whole reduction process.The following work has been carried out:(i)the model-reduction theory is addressed for typical Warburg elements and RC circuits based on the continued fraction expansion theory and the response error minimization technique,respectively;(ii)the order effect on the model reduction of typical Warburg elements is quantitatively evaluated by time–frequency analysis;(iii)the results of time–frequency analysis are confirmed to be useful to determine the reduction order in terms of the kinetic information needed to be captured;and(iv)the results of time–frequency analysis are validated for the model reduction of fractional impedance spectra for lithium-ion batteries,supercapacitors,and solid oxide fuel cells.In turn,the numerical validation has demonstrated the powerful function of the joint time–frequency analysis.The thorough model reduction of fractional impedance spectra addressed in the present work not only clarifies the relationship between time-domain transient analysis and frequency-domain stationary analysis but also enhances the reliability of the joint time–frequency analysis for electrochemical energy devices.
基金This work was supported by the National Key Research and Development Project(Nos.2019YFA0705403,2022YFA1205300)the National Natural Science Foundation of China(No.T2293693)+3 种基金the Guangdong Innovative and Entrepreneurial Research Team Program(No.2017ZT07C341)the Guangdong Basic and Applied Basic Research Foundation(No.2020B0301030002)the Shenzhen Basic Research Project(Nos.WDZC20200824091903001,JSGG20220831105402004)Zhiyuan Xiong thanks the financial support from South China University of Technology.
文摘Hexagonal boron nitride nanosheets(BNNSs)exhibit remarkable thermal and dielectric properties.However,their self-assembly and alignment in macroscopic forms remain challenging due to the chemical inertness of boron nitride,thereby limiting their performance in applications such as thermal management.In this study,we present a coaxial wet spinning approach for the fabrication of BNNSs/polymer composite fibers with high nanosheet orientation.The composite fibers were prepared using a superacid-based solvent system and showed a layered structure comprising an aramid core and an aramid/BNNSs sheath.Notably,the coaxial fibers exhibited significantly higher BNNSs alignment compared to uniaxial aramid/BNNSs fibers,primarily due to the additional compressive forces exerted at the core-sheath interface during the hot drawing process.With a BNNSs loading of 60 wt%,the resulting coaxial fibers showed exceptional properties,including an ultrahigh Herman orientation parameter of 0.81,thermal conductivity of 17.2 W m^(-1)K^(-1),and tensile strength of 192.5 MPa.These results surpassed those of uniaxial fibers and previously reported BNNSs composite fibers,making them highly suitable for applications such as wearable thermal management textiles.Our findings present a promising strategy for fabricating high-performance composite fibers based on BNNSs.
基金supported by the Open Research Found of Songshan Lake Materials Laboratory(2021SLABFN04)Guangdong Basic and Applied Basic Research Foundation(2022A1515010920)+2 种基金Inner Mongolia Major Science and Technology Project(2020ZD0024)the Alashan League’s Project of Applied Technology Research and Development Fund(AMYY2020-01)the Local Science and Technology Development Project of the Central Government(2022ZY0011)
文摘Calcium-ion batteries have been considered attractive candidates for large-scale energy storage applications due to their natural abundance and low redox potential of Ca^(2+)/Ca.However,current calcium ion technology is still hampered by the lack of high-capacity and long-life electrode materials to accommodate the large Ca^(2+)(1.00Å).Herein,an amorphous vanadium structure induced by Mo doping and in-situ electrochemical activation is reported as a high-rate anode material for calcium ion batteries.The doping of Mo could destroy the lattice stability of VS4 material,enhancing the flexibility of the structure.The following electrochemical activation further converted the material into sulfide and oxides co-dominated composite(defined as MoVSO),which serves as an active material for the storage of Ca^(2+)during cycling.Consequently,this amorphous vanadium structure exhibits excellent rate capability,achieving discharge capacities of 306.7 and 149.2 mAh g^(-1)at 5 and 50 A g^(-1)and an ultra-long cycle life of 2000 cycles with 91.2%capacity retention.These values represent the highest level to date reported for calcium ion batteries.The mechanism studies show that the material undergoes a partial phase transition process to derive MoVSO.This work unveiled the calcium storage mechanism of vanadium sulfide in aqueous electrolytes and accelerated the development of high-performance aqueous calcium ion batteries.
基金We acknowledge the National Natural Science Foundation of China(No.22275134)for fi nancial support.
文摘N-doped carbon materials,with their applications as electrocatalysts for the oxygen reduction reaction(ORR),have been extensively studied.However,a negletcted fact is that the operating potential of the ORR is higher than the theoretical oxida-tion potential of carbon,possibly leading to the oxidation of carbon materials.Consequently,the infl uence of the structural oxidation evolution on ORR performance and the real active sites are not clear.In this study,we discover a two-step oxida-tion process of N-doped carbon during the ORR.The fi rst oxidation process is caused by the applied potential and bubbling oxygen during the ORR,leading to the oxidative dissolution of N and the formation of abundant oxygen-containing functional groups.This oxidation process also converts the reaction path from the four-electron(4e)ORR to the two-electron(2e)ORR.Subsequently,the enhanced 2e ORR generates oxidative H_(2)O_(2),which initiates the second stage of oxidation to some newly formed oxygen-containing functional groups,such as quinones to dicarboxyls,further diversifying the oxygen-containing functional groups and making carboxyl groups as the dominant species.We also reveal the synergistic eff ect of multiple oxygen-containing functional groups by providing additional opportunities to access active sites with optimized adsorption of OOH*,thus leading to high effi ciency and durability in electrocatalytic H_(2)O_(2) production.
基金the fund provided by NAPATA program,jointly funded by France campus and the Ministry of Higher Education and Scientific research,SudanLab facilities provided by LERMAB which is supported by a grant of the French Agence Nationale de la Recherche(ANR)in the ambit of the laboratory of excellence(Labex)ARBRE is also aknowledged.
文摘Tannin was extracted from different subspecies of Acacia nilotica,Acacia nilotica nilotica(Ann),Acacia nilotica tomentosa(Ant)and Acacia nilotica adansonii(Ana).The aim was to elucidate their structure and evaluate their reactivity as bioadhesives in the wood industry.The extracts were prepared by hot water extraction(90°C tem-perature).Their gel time with paraformaldehyde was used atfirst to compare their reactivity.The tannin contents and the percentage of total polyphenolic materials in different solutions of the extracts spray dried powder were determined by the hide powder method.Concentrated solutions(47%)were tested by both MALDI ToF,13CNMR.The thermomechanical analysis(TMA)was performed to evaluate their modulus of elasticity(MOE)at different pHs.The gel times of all the three tannin extracts showed that their reactivity and it was com-parable to other known procyanidin/prodelphinidin tannin extract types.Ana,Ann and Ant showed highest per-cent of total polyphenolic materials at 70%,64%,and 57%,respectively.The 13CNMR spectra showed that the three subspecies of condensed tannins were mainly constituted of procyanidins(PC)and prodelphinidins(PD)in slightly different ratios.Ann(56.5%PC and 43.4%PD),Ant(57%PC and 43%PD)and Ana(58%PC and 42%PD).MALDI–TOF spectra showed the presence offlavonoid monomers,and oligomers some of which linked to short carbohydrates monomers or dimers.TMA revealed that the three types of tannins had high MOE at their initial pH(5).
基金financially supported by the National Key Research and Development Program of China(Nos.2022YFA1505700 and 2019YFA0210403)the National Natural Science Foundation of China(Nos.22205232 and 21601187)+2 种基金the Talent Plan of Shanghai Branch,Chinese Academy of Sciences(No.CASSHB-QNPD-2023-020)the Natural Science Foundation of Fujian Province(Nos.2023J06044 and 2023J01213)the Fund for Distinguished Young Scholars of FJIRSM(No.CXZX-2022-JQ06)。
文摘Electrochemical nitrate reduction to NH_(3)holds a great promise for N-upcycling in nature,while its sluggish reaction kinetics involved in both the stepwise deoxygenation and hydrogenation processes necessitates the development of bespoke catalysts with multi-site engineering.Herein,we report a hybrid catalyst composed of rare-earth(RE)yttrium(Y)single atoms and copper phosphide(Cu_(3)P)nanoparticles loaded on N,P-doped carbon(Y_(SA)-Cu_(3)P/CNP)through a chelating and pyrolysis method.Owing to a synergistic contribution of Y single atoms and Cu_(3)P nanoparticles,Y_(SA)-Cu_(3)P/CNP achieves an impressive NH_(3)Faradaic efficiency(FE)of 92%at-0.5V(vs.RHE)and the highest NH_(3)yield rate of11.4 mg·h^(-1)·cm^(-2)at-0.6 V(vs.RHE)in an alkaline media,which surpass most of the reported electrocatalysts.The intricate reaction pathway has been explored by online differential electrochemical mass spectrometry(DEMS),and the synergistic effect between Y single atoms and Cu_(3)P nanoparticles has been studied by in situ synchrotron X-ray absorption spectroscopy.Moreover,density-functional theory(DFT)calculations unveil that the high-efficiency nitrate reduction on Y_(SA)-Cu_(3)P/CNP is attributed to a reduced energy barrier of the rate-determining deoxygenation step coupled with the enhanced stabilization of active hydrogen favorable for the hydrogenation steps,thereby boosting the overall reaction rates.In addition,a prototype Zn-nitrate battery utilizing Y_(SA)-Cu_(3)P/CNP as the cathode is unveiled.This work not only elucidates the mechanism behind the enhanced catalytic performance but also paves the way for the future development of highefficiency electrocatalysts through dual-site engineering.
基金supported by the National Natural Science Foundation of China(51762014,52231007,12327804,T2321003,22088101)in part by the National Key Research Program of China under Grant 2021YFA1200600.
文摘Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(generally 5%–10%)during Li^(+)storage causes unsatisfactory long-term cyclability.Here,“zero-strain”NiNb_(2)O_(6) fibers are explored as a new anode material with comprehensively good electrochemical properties.During Li^(+)storage,the expansion of electrochemical inactive NiO_(6) octahedra almost fully offsets the shrinkage of active NbO_(6) octahedra through reversible O movement.Such superior volume-accommodation capability of the NiO_(6) layers guarantees the“zero-strain”behavior of NiNb_(2)O_(6) in a broad temperature range(0.53%//0.51%//0.74%at 25//−10//60℃),leading to the excellent cyclability of the NiNb_(2)O_(6) fibers(92.8%//99.2%//91.1%capacity retention after 1000//2000//1000 cycles at 10C and 25//−10//60℃).This NiNb_(2)O_(6) material further exhibits a large reversible capacity(300//184//318 mAh g−1 at 0.1C and 25//−10//60℃)and outstanding rate performance(10 to 0.5C capacity percentage of 64.3%//50.0%//65.4%at 25//−10//60℃).Therefore,the NiNb_(2)O_(6) fibers are especially suitable for large-capacity,fast-charging,long-life,and all-climate lithium-ion batteries.
文摘The electrolysis of alkaline seawater is critical for sustainable hydrogen production but is hindered by the sluggish oxygen evolution reaction in saline environments.Advanced electrocatalysts with tailored structures and electronic properties are essential,and phase engineering provides a transformative approach by modulating crystallographic symmetry and electronic configurations.Two-dimensional(2D)LaMnO_(3) perovskites show promise due to their exposed active sites and tunable electronic properties.However,the conventional stable rhombohedral phase limits oxygen diffusion despite good electron transport.Unconventional metastable phases with superior symmetry enhance lattice oxygen activity in saline environments but are challenging to synthesize.Herein,we propose a microwave shock method incorporating Co atoms to rapidly produce 2D LaMnO_(3) in rhombohedral,hexagonal,and metastable cubic phases.This strategy circumvents the limitations of high-temperature synthesis,preserving the 2D morphology while enabling the formation of metastable cubic phases.The metastable cubic phase exhibits superior OER activity and stability even in alkaline seawater due to optimal symmetry,interlayer spacing,and Mn-O covalency.X-ray absorption spectroscopy and theoretical calculations further highlight its balanced oxygen adsorption and desorption.This work underscores the role of metastable phase engineering in advancing seawater electrolysis and establishes a scalable route for designing high-performance 2D electrocatalysts.
基金supported by the National Natural Science Foundation of China(No.22208322)the Natural Science Foundation of Henan(No.242300421230)+1 种基金the Key Research Projects of Higher Education Institutions of Henan Province(No.24A530009)the Special Fund for Young Teachers from Zhengzhou University(No.JC23257011).
文摘Designing advanced electrocatalysts with high methanol tolerance in the oxygen reduction reaction process is crucial for the sustainable implementation of direct methanol fuel cells.Herein,we present a Pt/C catalyst modified with black phosphorus(BP)nanodots(BPNDs-Pt/C)by using a facile ultrasonic mixing method.Experimental and computational investigations reveal that the electron transfer from BP to Pt leads to weak adsorption of hydroxyl groups on the Pt surface.As a result,the BPNDs-Pt/C catalyst exhibits efficient activity and anti-methanol ability for cathodic oxygen reduction electrocatalysis in an acidic medium.Additionally,it demonstrates high activity for oxygen reduction reaction(ORR)in an alternative alkaline system with cation exchange membrane and eliminable methanol penetration.This work highlights the feasibility of using non-metallic elements to regulate the electronic structure and surface properties of Pt-based nanomaterials.Furthermore,the designed BPNDs-Pt/C electrocatalyst,with controllable ORR performance,can be applied across various scenarios based on demand.
基金National Natural Science Foundation of China (NSFC)(52273266, U2001216)Shenzhen Science and Technology Innovation Committee (20231121102401001)+2 种基金Shenzhen Key Laboratory Project (ZDSYS201602261933302)GuangdongHong Kong-Macao Joint Laboratory on Micro-Nano Manufacturing Technology (2021LSYS004)SUSTech high level special funds (G03050K002)。
文摘Widely used spin-coated nickle oxide (NiOx) based perovskite solar cells often suffer from severe interfacial reactions between the NiOxand adjacent perovskite layers due to surface defect states,which inherently impair device performance in a long-term view,even with surface molecule passivation.In this study,we developed high-quality magnetron-sputtered NiOxthin films through detailed process optimization,and compared systematically sputtered and spin-coated NiOxthin film surfaces from materials to devices.These sputtered NiOxfilms exhibit improved crystallinity,smoother surfaces,and significantly reduced Ni3+or Ni vacancies compared to their spin-coated counterparts.Consequently,the interface between the perovskite and sputtered NiOxfilm shows a substantially reduced density of defect states.Perovskite solar cells (PSCs) fabricated with our optimally sputtered NiOxfilms achieved a high power conversion efficiency (PCE) of up to 19.93%and demonstrated enhanced stability,maintaining 86.2% efficiency during 500 h of maximum power point tracking under one standard sun illumination.Moreover,with the surface modification using (4-(2,7-dibromo-9,9-dimethylacridin-10(9H)-yl)butyl)p hosphonic acid (DMAcPA),the device PCE was further promoted to 23.07%,which is the highest value reported for sputtered NiOxbased PSCs so far.
基金supported by the National Natural Science Foundation of China (Nos. 22074072, 22274083)the Shandong Provincial Natural Science Foundation (Nos. ZR2022LZY022, ZR2023LZY005)+2 种基金the Science and Technology Planning Project of South District of Qingdao City (No. 2022–4–005-YY)the Exploration project of the State Key Laboratory of Bio Fibers and Eco Textiles of Qingdao University (No. TSKT202101)the High-Level Discipline Project of Shandong Province。
文摘Glioma is the most common malignant tumor of the brain. The postoperative recurrence rate was high,and the 2-year survival rate only increased by 20%–25%. The reason is the blood-brain barrier(BBB). BBB is a physical barrier that stabilizes the physiological environment of brain tissue and protects the central nervous system from the invasion of harmful substances. Drug delivery based on nanotechnology and nanocarriers has attracted much attention due to its biological safety, continuous drug release time,increasing solubility, biological drug activity, and enhanced BBB permeability. By modifying different substances on the surface of nanocarriers, the BBB is bypassed by receptor-mediated and cell endocytosis and exocytosis. In addition, the purpose of bypassing BBB-targeted drug delivery can also be achieved by intranasal administration and local administration. This paper reviews different target transport mechanisms, mainly in invasive and non-invasive strategies, the nanocarriers that have made progress and the nanocarrier strategy of bypassing BBB are listed.
文摘Single-metal sites anchored in nitrogen-doped nanocarbons are recognized as potent electrocatalysts for applications in energy conversion and storage.Here,an innovative inorganic salt-mediated secondary calcination strategy was developed to construct robust Pt single-atom catalysts on nitrogen-and oxygen-doped graphene nanosheets(Pt-N/O-GNs),thereby significantly enhancing the efficiency of the electrocatalytic oxygen reduction reaction(ORR).The ultrathin N/O-GNs,obtained by stripping Zn-ZIF with auxiliaries of KCl and LiCl,provide stable anchoring sites for highly exposed Pt-N_(3)O active structures.The Pt-N/O-GNs catalyst,featuring a low Pt loading of 0.44 wt%,demonstrates exceptional mass activity in the ORR process.It attains an impressive onset potential of 0.99 V and a half-wave potential of 0.88 V.The zinc-air battery driven by the Pt-N/O-GNs displays superior power density and cycle stability.Theoretical computational studies reveal that the structure of heteroatoms doped in few-layer graphene facilitates the stable anchoring of single-atom configurations.The findings provide new perspectives for the tailored design and fabrication of single-metal-site electrocatalysts.
基金financially supported by the Key Basic Research Project of Shandong Province(No.ZR2019ZD49)Taishan Scholar Foundation of Shandong Province(No.tstp20230627)Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences。
文摘Single-walled carbon nanotubes(SWNTs)with enriched(n,m)species are in high demand for various advanced applications.Since the SWNT structure is largely influenced by the chemistry of the active catalyst during growth process,exploiting novel catalyst with bias towards specific SWNT chiralities has been challenging.In this work,we introduce a vanadium catalyst supported by mesoporous magnesia(V-MgO)for the selective growth of SWNTs using CO chemical vapor deposition(CVD).At a reaction temperature of 650℃,the(6,5)SWNT content reaches an impressive 67.9%among all semiconducting species,exceeding the selectivity of many commercial SWNT products.Post-CVD analysis reveals that the catalyst transforms into vanadium carbide(VC),which acts as a nucleation site for SWNT growth.Molecular dynamics simulations indicate that the energy at the SWNT-VC interface and the growth kinetics of SWNTs contribute to the chirality selectivity.This research opens up possibilities for the selective synthesis of SWNTs using cost-effective early transition metals,illuminating their future applications in fields such as bioimaging.
基金supported by the Qingdao Jiuhuanxinyue New Energy Technology Co.,Ltd.the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021B1515120071)+2 种基金the 21C Innovation Laboratory,Contemporary Amperex Technology Ltd.(Grant No.21C-OP-202112)the financial support from the Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515011873)the Shenzhen Science and Technology Program(Grant No.JCYJ20220531095212027).
文摘Li metal is widely recognized as the desired anode for next-generation energy storage,Li metal batteries,due to its highest theoretical capacity and lowest potential.Nonetheless,it suffers from unstable electrochemical behaviors like dendrite growth and side reactions in practical application.Herein,we report a highly stable anode with collector,Li_(5)Mg@Cu,realized by the melting-rolling process.The Li_(5)Mg@Cu anode delivers ultrahigh cycle stability for 2000 and 1000 h at the current densities of 1 and 2 mA cm^(-2),respectively in symmetric cells.Meanwhile,the Li_(5)Mg@Cu|LFP cell exhibits a high-capacity retention of 91.8% for 1000 cycles and 78.8% for 2000 cycles at 1 C.Moreover,we investigate the suppression effects of Mg on the dendrite growth by studying the performance of Li_(x)Mg@Cu electrodes with different Mg contents(2.0-16.7 at%).The exchange current density,surface energy,Li^(+)diffusion coefficient,and chemical stability of Li_(x)Mg@Cu concretely reveal this improving suppression effect when Mg content becomes higher.In addition,a Mg-rich phase with“hollow brick”morphology forming in the high Mg content Li_(x)Mg@Cu guides the uniform deposition of Li.This study reveals the suppression effects of Mg on Li dendrites growth and offers a perspective for finding the optimal component of Li-Mg alloys.
