This study presents a facile and rapid method for synthesizing novel Layered Double Hydroxide(LDH)nanoflakes,exploring their application as a photocatalyst,and investigating the influence of condensed phosphates'g...This study presents a facile and rapid method for synthesizing novel Layered Double Hydroxide(LDH)nanoflakes,exploring their application as a photocatalyst,and investigating the influence of condensed phosphates'geometric linearity on their photocatalytic properties.Herein,the Mg O film,obtained by plasma electrolysis of AZ31 Mg alloys,was modified by growing an LDH film,which was further functionalized using cyclic sodium hexametaphosphate(CP)and linear sodium tripolyphosphate(LP).CP acted as an enhancer for flake spacing within the LDH structure,while LP changed flake dispersion and orientation.Consequently,CP@LDH demonstrated exceptional efficiency in heterogeneous photocatalysis,effectively degrading organic dyes like Methylene blue(MB),Congo red(CR),and Methyl orange(MO).The unique cyclic structure of CP likely enhances surface reactions and improves the catalyst's interaction with dye molecules.Furthermore,the condensed phosphate structure contributes to a higher surface area and reactivity in CP@LDH,leading to its superior photocatalytic performance compared to LP@LDH.Specifically,LP@LDH demonstrated notable degradation efficiencies of 93.02%,92.89%,and 88.81%for MB,MO,and CR respectively,over a 40 min duration.The highest degradation efficiencies were observed in the case of the CP@LDH sample,reporting 99.99%for MB,98.88%for CR,and 99.70%for MO.This underscores the potential of CP@LDH as a highly effective photocatalyst for organic dye degradation,offering promising prospects for environmental remediation and water detoxification applications.展开更多
The hybridization of metal-organic framework(MOF)with inorganic layers would lead to the discovery of novel hybrid materials that can provide a compelling strategy for enhancing its photocatalytic and electrochemical ...The hybridization of metal-organic framework(MOF)with inorganic layers would lead to the discovery of novel hybrid materials that can provide a compelling strategy for enhancing its photocatalytic and electrochemical response.In the present study,a highly efficient multifunctional hybrid material was developed by exploiting the defective layer formed on AZ31 Mg alloy through plasma electrolytic oxidation(PEO)as a nucleation and growth site for Co-MOF.The concentrations of the organic linker 2-Methylimidazole(2,MIm)and cobalt nitrate as a source of Co^(2+) ions were varied to control the growth of the obtained Co-MOF.Lower concentrations of the 2,MIm ligand favored the formation of leaf-like MOF structures through an anisotropic,two-dimensional growth,while higher concentrations led to rapid,isotropic nucleation and the creation of polyhedral Co-MOF structures.The sample characterized by polyhedral Co-MOF structures exhibited superior electrochemical stability,with the lowest corrosion current density(3.11×10^(-9) A/cm^(2))and the highest top layer resistance(2.34×10^(6)Ωcm^(2)),and demonstrated outstanding photocatalytic efficiency,achieving a remarkable 99.98%degradation of methylene blue,an organic pollutant,in model wastewater.To assess the active adsorption sites of the Co-MOF,density functional theory(DFT)was utilized.This study explores the changes in morphologies of the coatings of Co-MOF with the change of solution concentration to form coatings with enhanced properties on the metallic substrate,which could establish the groundwork for the development of next-generation multifunctional frameworks with diverse applications.展开更多
With the rapid advancement of computing and information technology at the turn of the 21st century,the power of data collection and processing has multiplied tremendously.Based on this a game-changing advancement,scie...With the rapid advancement of computing and information technology at the turn of the 21st century,the power of data collection and processing has multiplied tremendously.Based on this a game-changing advancement,science is at the advent of the “fourth paradigm”of massive data plus artificial intelligence,in which the efficiency of scientific research is continuously improved,research time is shortened,and research cost is reduced[1].展开更多
The poor reversibility of Zn anodes induced by dendrite growth,surface passivation,and corrosion,severely hinders the practical applicability of Zn metal batteries.To address these issues,a plasmaassisted aerogel(PAG)...The poor reversibility of Zn anodes induced by dendrite growth,surface passivation,and corrosion,severely hinders the practical applicability of Zn metal batteries.To address these issues,a plasmaassisted aerogel(PAG)interface engineering was proposed as efficient ion transport modulator that can simultaneously regulate uniform Zn^(2+)flux and desolvation behavior during battery operation.The PAG with ordered mesopores acted as an ion sieve to homogenize Zn deposition and accelerate Zn^(2+)flux,which is favorable for corrosion resistance and dendrite suppression.Importantly,the plasma-assisted aerogel with abundant hydrophilic groups can facilitate the desolvation kinetics of Zn^(2+)due to the multiple hydrogen-bonding interaction with the activated water molecules,thus accelerating the Zn^(2+)migration kinetics.Consequently,the Zn/Zn cell assembled with PAG-modified separator demonstrates stable plating and stripping behavior(over 1400 h at 1 mA cm^(-2))and high Coulombic efficiency(99.8%at1 mA cm^(-2)after 1100 cycles),and the Zn‖MnO_(2)full cell shows excellent long-term cycling stability and maintains a high capacity of 154.9 mA h g^(-1)after 1000 cycles at 1 A g^(-1).This study provides a feasible approach for the large-scale fabrication of aerogel functionalized separators to realize ultra-stable Zn metal batteries.展开更多
This paper studies the antimicrobial activity of selected engineering materials surfaces at room and chill temperatures. The antimicrobial effects of selected materials surfaces were evaluated by dropping the test pie...This paper studies the antimicrobial activity of selected engineering materials surfaces at room and chill temperatures. The antimicrobial effects of selected materials surfaces were evaluated by dropping the test pieces into prepared cultures of Bacillus spp, Escherichia coli, and Staphylococcus aereus isolated from fruits, animal feaces and natural environment respectively. Bacteria count obtained after 0, 30, 60, 90, 120, 180, 240 and 300 minutes at room temperature and chill condition was taken and compared with their initial count. The amount of live bacteria drops by several orders of magnitude, to zero, on metallic copper and brass within 30 to 300 minutes in both room and chill conditions. In contrast, no reduction is seen in the number of colonies of live bacteria on plastics, ceramic and stainless steel in both room and chill conditions. These results suggest that the selection of metallic copper and brass for touch surfaces in hospitals, surfaces exposed to fruit processing and household utensils can materially assist in reducing bacterial contamination, which should lead to a reduction in the transmission of infectious organisms.展开更多
Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategie...Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.展开更多
Electrocatalytic water splitting seems to be an efficient strategy to deal with increasingly serious environmental problems and energy crises but still suffers from the lack of stable and efficient electrocatalysts.De...Electrocatalytic water splitting seems to be an efficient strategy to deal with increasingly serious environmental problems and energy crises but still suffers from the lack of stable and efficient electrocatalysts.Designing practical electrocatalysts by introducing defect engineering,such as hybrid structure,surface vacancies,functional modification,and structural distortions,is proven to be a dependable solution for fabricating electrocatalysts with high catalytic activities,robust stability,and good practicability.This review is an overview of some relevant reports about the effects of defect engineering on the electrocatalytic water splitting performance of electrocatalysts.In detail,the types of defects,the preparation and characterization methods,and catalytic performances of electrocatalysts are presented,emphasizing the effects of the introduced defects on the electronic structures of electrocatalysts and the optimization of the intermediates'adsorption energy throughout the review.Finally,the existing challenges and personal perspectives of possible strategies for enhancing the catalytic performances of electrocatalysts are proposed.An in-depth understanding of the effects of defect engineering on the catalytic performance of electrocatalysts will light the way to design high-efficiency electrocatalysts for water splitting and other possible applications.展开更多
MXenes,the most recent addition to the 2D material family,have attracted significant attention owing to their distinctive characteristics,including high surface area,conductivity,surface characteristics,mechanical str...MXenes,the most recent addition to the 2D material family,have attracted significant attention owing to their distinctive characteristics,including high surface area,conductivity,surface characteristics,mechanical strength,etc.This review begins by presenting MXenes,providing insights into their structural characteristics,synthesis methods,and surface functional groups.The review covers a thorough analysis of MXene surface properties,including surface chemistry and termination group impacts.The properties of MXenes are influenced by their synthesis,which can be fluorine-based or fluorinedependent.Fluorine-based synthesis techniques involve etching with fluorine-based reagents,mainly including HF or LiF/HCl,while fluorine-free methods include electrochemical etching,chemical vapor deposition(CVD),alkaline etching,Lewis acid-based etching,etc.These techniques result in the emergence of functional groups such as-F,-O,-OH,-Cl,etc.on the MXenes surface,depending on the synthesis method used.Properties of MXenes,such as electrical conductivity,electronic properties,catalytic activity,magnetic properties,mechanical strength,and chemical and thermal stability,are examined,and the role of functional groups in determining these properties is explored.The review delves into the diverse applications of MXenes,encompassing supercapacitors,battery materials,hydrogen storage,fuel cells,electromagnetic interference(EMI) shielding,pollutant removal,water purification,flexible electronics,sensors,additive manufacturing,catalysis,biomedical and healthcare fields,etc.Finally,this article outlines the challenges and opportunities in the current and future development of MXenes research,addressing various aspects such as synthesis scalability,etching challenges,and multifunctionality,and exploring novel applications.The review concludes with future prospects and conclusions envisioning the impact of MXenes on future technologies and innovation.展开更多
3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal route.The as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spec...3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal route.The as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spectroscopy (EDS),scanning electron microscopy (SEM) and Raman.SEM images of the samples reveal that the hierarchical flowerlike WS_(2) microspheres with diameters of about 3-5μm are composed of a number of curled nanosheets.Electrochemical tests such as charge/discharge,cyclic voltammetry,cycle life and rate performance were carried out on the WS_(2) sample.As an anode material for lithium-ion batteries,hierarchical flowerlike WS_(2) microspheres show excellent electrochemical performance.At a current density of100 mA·g^(-1),a high specific capacity of 647.8 mA·h·g^(-1) was achieved after 120 discharge/charge cycles.The excellent electrochemical performance of WS_(2) as an anode material for lithium-ion batteries can be attributed to its special 3D hierarchical structure.展开更多
The new-generation electronic components require a balance between electromagnetic interference shielding efficiency and open structure factors such as ventilation and heat dissipation.In addition,realizing the tunabl...The new-generation electronic components require a balance between electromagnetic interference shielding efficiency and open structure factors such as ventilation and heat dissipation.In addition,realizing the tunable shielding of porous shields over a wide range of wavelengths is even more challenging.In this study,the well-prepared thermoplastic polyurethane/carbon nanotubes composites were used to fabricate the novel periodic porous flexible metamaterials using fused deposition modeling 3D printing.Particularly,the investigation focuses on optimization of pore geometry,size,dislocation configuration and material thickness,thus establishing a clear correlation between structural parameters and shielding property.Both experimental and simulation results have validated the superior shielding performance of hexagon derived honeycomb structure over other designs,and proposed the failure shielding size(D_(f)≈λ/8-λ/5)and critical inclined angle(θf≈43°-48°),which could be used as new benchmarks for tunable electromagnetic shielding.In addition,the proper regulation of the material thickness could remarkably enhance the maximum shielding capability(85-95 dB)and absorption coefficient A(over 0.83).The final innovative design of the porous shielding box also exhibits good shielding effectiveness across a broad frequency range(over 2.4 GHz),opening up novel pathways for individualized and diversified shielding solutions.展开更多
With the diversified development of big data,detection and precision guidance technologies,electromagnetic(EM)functional materials and devices serving multiple spectrums have become a hot topic.Exploring the multispec...With the diversified development of big data,detection and precision guidance technologies,electromagnetic(EM)functional materials and devices serving multiple spectrums have become a hot topic.Exploring the multispectral response of materials is a challenging and meaningful scientific question.In this study,MXene/TiO_(2)hybrids with tunable conduction loss and polarization relaxation are fabricated by in situ atomic reconstruction engineering.More importantly,MXene/TiO_(2)hybrids exhibit adjustable spectral responses in the GHz,infrared and visible spectrums,and several EM devices are constructed based on this.An antenna array provides excellent EM energy harvesting in multiple microwave bands,with|S11|up to−63.2 dB,and can be tuned by the degree of bending.An ultra-wideband bandpass filter realizes a passband of about 5.4 GHz and effectively suppresses the transmission of EM signals in the stopband.An infrared stealth device has an emissivity of less than 0.2 in the infrared spectrum at wavelengths of 6-14μm.This work can provide new inspiration for the design and development of multifunctional,multi-spectrum EM devices.展开更多
The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in ele...The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in electrochemical acetonitrile reduction reaction(ARR)to date.Herein,we successfully realize the structural transformation of Pd Cu metallic aerogels(MAs)from face-centered cubic(FCC)to body-centered cubic(BCC)through annealing treatment.Specifically,the BCC Pd Cu MAs exhibit excellent ARR performance with high ethylamine selectivity of 90.91%,Faradaic efficiency of 88.60%,yield rate of 316.0 mmol h^(-1)g^(-1)_(Pd+Cu)and long-term stability for consecutive electrolysis within 20 h at-0.55 V vs.reversible hydrogen electrode,outperforming than those of FCC Pd Cu MAs.Under the membrane electrode assembly system,BCC Pd Cu MAs also demonstrate excellent ethylamine yield rate of 389.5 mmol h^(-1)g^(-1)_(Pd+Cu).Density functional theory calculation reveals that the d-d orbital coupling in BCC Pd Cu MAs results in an evident correlation effect for the interaction of Pd and Cu sites,which boosts up the Cu sites electronic activities to enhance ARR performance.Our work opens a new route to develop efficient ARR electrocatalysts from the perspective of crystalline structure transformation.展开更多
Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,bu...Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,but seldom do they exhibit excellent selectivity toward formate.In this article,we demonstrate that a heterointerface catalyst ZnO/ZnSnO3 with nanosheet morphology shows enhanced selectivity with a maximum Faradaic efficiency(FE)of 86%at−0.9 V versus reversible hydrogen electrode and larger current density for the conversion of CO_(2) to formate than pristine ZnO and ZnSnO3.In particular,the FEs of the C1 products(CO+HCOO−)exceed 98%over the potential window.The experimental measurements combined with theoretical calculations revealed that the ZnO in ZnO/ZnSnO3 heterojunction delivers the valence electron depletion and accordingly optimizes Zn d-band center,which results in moderate Zn-O hybridization of HCOO*and weakened Zn-C hybridization of competing COOH*,thus greatly boosting the HCOOH generation.Our study highlights the importance of charge redistribution in catalysts on the selectivity of electrochemical CO_(2) reduction.展开更多
Metalenses with achromatic performance offer a new opportunity for high-quality imaging with an ultracompact configuration;however,they suffer from complex fabrication processes and low focusing efficiency.In this stu...Metalenses with achromatic performance offer a new opportunity for high-quality imaging with an ultracompact configuration;however,they suffer from complex fabrication processes and low focusing efficiency.In this study,we propose an efficient design method for achromatic microlenses on a wavelength scale using materials with low dispersion,an adequately designed convex surface,and a thickness profile distribution.By taking into account the absolute chromatic aberration,relative focal length shift(FLS),and numerical aperture(NA),microlens with a certain focal length can be realized through our realized map of geometric features.Accordingly,the designed achromatic microlenses with low-dispersion fused silica were fabricated using a focused ion beam,and precise surface profiles were obtained.The fabricated microlenses exhibited a high average focusing efficiency of 65%at visible wavelengths of 410-680 nm and excellent achromatic capability via white light imaging.Moreover,the design exhibited the advantages of being polarization-insensitive and near-diffraction-limited.These results demonstrate the effectiveness of our proposed achromatic microlens design approach,which expands the prospects of miniaturized optics such as virtual and augmented reality,ultracompact microscopes,and biological endoscopy.展开更多
Ferritic/martensitic(F/M)steel is widely used as a structural material in thermal and nuclear power plants.However,it is susceptible to intergranular damage,which is a critical issue,under service conditions.In this s...Ferritic/martensitic(F/M)steel is widely used as a structural material in thermal and nuclear power plants.However,it is susceptible to intergranular damage,which is a critical issue,under service conditions.In this study,to improve the resistance to intergranular damage of F/M steel,a thermomechanical process(TMP)was employed to achieve a grain boundary engineering(GBE)microstructure in F/M steel P92.The TMP,including cold-rolling thickness reduction of 6%,9%,and 12%,followed by austenitization at 1323 K for 40 min and tempering at 1053 K for 45 min,was applied to the as-received(AR)P92 steel.The prior austenite grain(PAG)size,prior austenite grain boundary character distribution(GBCD),and connectivity of prior austenite grain boundaries(PAGBs)were investigated.Compared to the AR specimen,the PAG size did not change significantly.The fraction of coincident site lattice boundaries(CSLBs,3≤Σ≤29)and Σ3^(n) boundaries along PAGBs decreased with increasing reduction ratio because the recrystallization fraction increased with increasing reduction ratio.The PAGB connectivity of the 6%deformed specimen slightly deteriorated compared with that of the AR specimen.Moreover,potentiodynamic polarization studies revealed that the intergranular damage resistance of the studied steel could be improved by increasing the fraction of CSLBs along the PAGBs,indicating that the TMP,which involves low deformation,could enhance the intergranular damage resistance.展开更多
Solid-state lithium batteries(SSLBs)with high safety have emerged to meet the increasing energy density demands of electric vehicles,hybrid electric vehicles,and portable electronic devices.However,the dendrite format...Solid-state lithium batteries(SSLBs)with high safety have emerged to meet the increasing energy density demands of electric vehicles,hybrid electric vehicles,and portable electronic devices.However,the dendrite formation,high interfacial resistance,and deleterious interfacial reactions caused by solid-solid contact between electrode and electrolyte have hindered the commercialization of SSLBs.Thus,in this review,the state-of-the-art developments in the rational design of solid-state electrolyte and their progression toward practical applications are reviewed.First,the origin of interface instability and the sluggish charge carrier transportation in solid-solid interface are presented.Second,various strategies toward stabilizing interfacial stability(reducing interfacial resistance,suppressing lithium dendrites,and side reactions)are summarized from the physical and chemical perspective,including building protective layer,constructing 3D and gradient structures,etc.Finally,the remaining challenges and future development trends of solidstate electrolyte are prospected.This review provides a deep insight into solving the interfacial instability issues and promising solutions to enable practical high-energy-density lithium metal batteries.展开更多
Lithium-sulfur(Li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low cost.However,the development of high-energy density Li-S batteries ...Lithium-sulfur(Li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low cost.However,the development of high-energy density Li-S batteries with high loading of flammable sulfur faces the challenges of electrochemical performance degradation owing to the shuttle effect and safety issues related to fire or explosion accidents.In this work,we report a three-dimensional(3D)conductive nitrogen-doped carbon foam supported electrostatic self-assembled MXene-ammonium polyphosphate(NCF-MXene-APP)layer as a heat-resistant,thermally-insulated,flame-retardant,and freestanding host for Li-S batteries with a facile and costeffective synthesis method.Consequently,through the use of NCF-MXene-APP hosts that strongly anchor polysulfides,the Li-S batteries demonstrate outstanding electrochemical properties,including a high initial discharge capacity of 1191.6 mA h g^(-1),excellent rate capacity of 755.0 mA h g^(-1)at 1 C,and long-term cycling stability with an extremely low-capacity decay rate of 0.12%per cycle at 2 C.More importantly,these batteries can continue to operate reliably under high temperature or flame attack conditions.Thus,this study provides valuable insights into the design of safe high-performance Li-S batteries.展开更多
Although doped hole-transport materials(HTMs)off er an effi ciency benefi t for perovskite solar cells(PSCs),they inevi-tably diminish the stability.Here,we describe the use of various chlorinated small molecules,spec...Although doped hole-transport materials(HTMs)off er an effi ciency benefi t for perovskite solar cells(PSCs),they inevi-tably diminish the stability.Here,we describe the use of various chlorinated small molecules,specifi cally fl uorenone-triphenylamine(FO-TPA)-x-Cl[x=para,meta,and ortho(p,m,and o)],with diff erent chlorine-substituent positions,as dopant-free HTMs for PSCs.These chlorinated molecules feature a symmetrical donor-acceptor-donor structure and ideal intramolecular charge transfer properties,allowing for self-doping and the establishment of built-in potentials for improving charge extraction.Highly effi cient hole-transfer interfaces are constructed between perovskites and these HTMs by strategi-cally modifying the chlorine substitution.Thus,the chlorinated HTM-derived inverted PSCs exhibited superior effi ciencies and air stabilities.Importantly,the dopant-free HTM FO-TPA-o-Cl not only attains a power conversion effi ciency of 20.82% but also demonstrates exceptional stability,retaining 93.8%of its initial effi ciency even after a 30-day aging test conducted under ambient air conditions in PSCs without encapsulation.These fi ndings underscore the critical role of chlorine-substituent regulation in HTMs in ensuring the formation and maintenance of effi cient and stable PSCs.展开更多
The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was syn...The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> (OH)<sub>2</sub>, Li<sub>2</sub>CO<sub>3</sub> as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi<sub>0.4985</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> Mg<sub>0.0015</sub>O<sub>2</sub> cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm<sup>3</sup>. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.展开更多
Bi_(2)Te_(3)-based materials have drawn much attention from the thermoelectric community due to their excellent thermoelectric performance near room temperature.However,the stability of existing n-type Bi_(2)(Te,Se)_(...Bi_(2)Te_(3)-based materials have drawn much attention from the thermoelectric community due to their excellent thermoelectric performance near room temperature.However,the stability of existing n-type Bi_(2)(Te,Se)_(3)materials is still low due to the evaporation energy of Se(37.70 kJ mol^(-1))being much lower than that of Te(52.55 kJ mol^(-1)).The evaporated Se from the material causes problems in interconnects of the module while degrading the efficiency.Here,we have developed a new approach for the high-performance and stable n-type Se-free Bi_(2)Te_(3)-based materials bymaximizing the electronic transport while suppressing the phonon transport,at the same time.Spontaneously generated FeTe_(2)nanoinclusions within the matrix during the melt-spinning and subsequent spark plasma sintering is the key to simultaneous engineering of the power factor and lattice thermal conductivity.The nanoinclusions change the fermi level of the matrix while intensifying the phonon scattering via nanoparticles.With a fine-tuning of the fermi level with Cu doping in the n-type Bi_(2)Te_(3)-0.02FeTe_(2),a high power factor of∼41×10^(-4)Wm^(-1)K^(-2)with an average zT of 1.01 at the temperature range 300-470 K are achieved,which are comparable to those obtained in n-type Bi_(2)(Te,Se)_(3)materials.The proposed approach enables the fabrication of high-performance n-type Bi_(2)Te_(3)-based materials without having to include volatile Se element,which guarantees the stability of the material.Consequently,widespread application of thermoelectric devices utilizing the n-type Bi_(2)Te_(3)-based materials will become possible.展开更多
基金the National Research Foundation of Korea(NRF)funded by the Korean Government(MSIT)(No.2022R1A2C1006743)。
文摘This study presents a facile and rapid method for synthesizing novel Layered Double Hydroxide(LDH)nanoflakes,exploring their application as a photocatalyst,and investigating the influence of condensed phosphates'geometric linearity on their photocatalytic properties.Herein,the Mg O film,obtained by plasma electrolysis of AZ31 Mg alloys,was modified by growing an LDH film,which was further functionalized using cyclic sodium hexametaphosphate(CP)and linear sodium tripolyphosphate(LP).CP acted as an enhancer for flake spacing within the LDH structure,while LP changed flake dispersion and orientation.Consequently,CP@LDH demonstrated exceptional efficiency in heterogeneous photocatalysis,effectively degrading organic dyes like Methylene blue(MB),Congo red(CR),and Methyl orange(MO).The unique cyclic structure of CP likely enhances surface reactions and improves the catalyst's interaction with dye molecules.Furthermore,the condensed phosphate structure contributes to a higher surface area and reactivity in CP@LDH,leading to its superior photocatalytic performance compared to LP@LDH.Specifically,LP@LDH demonstrated notable degradation efficiencies of 93.02%,92.89%,and 88.81%for MB,MO,and CR respectively,over a 40 min duration.The highest degradation efficiencies were observed in the case of the CP@LDH sample,reporting 99.99%for MB,98.88%for CR,and 99.70%for MO.This underscores the potential of CP@LDH as a highly effective photocatalyst for organic dye degradation,offering promising prospects for environmental remediation and water detoxification applications.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(No.2022R1A2C1006743).
文摘The hybridization of metal-organic framework(MOF)with inorganic layers would lead to the discovery of novel hybrid materials that can provide a compelling strategy for enhancing its photocatalytic and electrochemical response.In the present study,a highly efficient multifunctional hybrid material was developed by exploiting the defective layer formed on AZ31 Mg alloy through plasma electrolytic oxidation(PEO)as a nucleation and growth site for Co-MOF.The concentrations of the organic linker 2-Methylimidazole(2,MIm)and cobalt nitrate as a source of Co^(2+) ions were varied to control the growth of the obtained Co-MOF.Lower concentrations of the 2,MIm ligand favored the formation of leaf-like MOF structures through an anisotropic,two-dimensional growth,while higher concentrations led to rapid,isotropic nucleation and the creation of polyhedral Co-MOF structures.The sample characterized by polyhedral Co-MOF structures exhibited superior electrochemical stability,with the lowest corrosion current density(3.11×10^(-9) A/cm^(2))and the highest top layer resistance(2.34×10^(6)Ωcm^(2)),and demonstrated outstanding photocatalytic efficiency,achieving a remarkable 99.98%degradation of methylene blue,an organic pollutant,in model wastewater.To assess the active adsorption sites of the Co-MOF,density functional theory(DFT)was utilized.This study explores the changes in morphologies of the coatings of Co-MOF with the change of solution concentration to form coatings with enhanced properties on the metallic substrate,which could establish the groundwork for the development of next-generation multifunctional frameworks with diverse applications.
文摘With the rapid advancement of computing and information technology at the turn of the 21st century,the power of data collection and processing has multiplied tremendously.Based on this a game-changing advancement,science is at the advent of the “fourth paradigm”of massive data plus artificial intelligence,in which the efficiency of scientific research is continuously improved,research time is shortened,and research cost is reduced[1].
基金financially supported by the National Natural Science Foundation of China(NSFC)(52203261)Natural Science Foundation of Jiangsu Province(BK20210474)the project of research on the industrial application of"controllable synthesis of nanocarbon-based polymer composites and their application in new energy”(N0.CJGJZD20210408092400002).
文摘The poor reversibility of Zn anodes induced by dendrite growth,surface passivation,and corrosion,severely hinders the practical applicability of Zn metal batteries.To address these issues,a plasmaassisted aerogel(PAG)interface engineering was proposed as efficient ion transport modulator that can simultaneously regulate uniform Zn^(2+)flux and desolvation behavior during battery operation.The PAG with ordered mesopores acted as an ion sieve to homogenize Zn deposition and accelerate Zn^(2+)flux,which is favorable for corrosion resistance and dendrite suppression.Importantly,the plasma-assisted aerogel with abundant hydrophilic groups can facilitate the desolvation kinetics of Zn^(2+)due to the multiple hydrogen-bonding interaction with the activated water molecules,thus accelerating the Zn^(2+)migration kinetics.Consequently,the Zn/Zn cell assembled with PAG-modified separator demonstrates stable plating and stripping behavior(over 1400 h at 1 mA cm^(-2))and high Coulombic efficiency(99.8%at1 mA cm^(-2)after 1100 cycles),and the Zn‖MnO_(2)full cell shows excellent long-term cycling stability and maintains a high capacity of 154.9 mA h g^(-1)after 1000 cycles at 1 A g^(-1).This study provides a feasible approach for the large-scale fabrication of aerogel functionalized separators to realize ultra-stable Zn metal batteries.
文摘This paper studies the antimicrobial activity of selected engineering materials surfaces at room and chill temperatures. The antimicrobial effects of selected materials surfaces were evaluated by dropping the test pieces into prepared cultures of Bacillus spp, Escherichia coli, and Staphylococcus aereus isolated from fruits, animal feaces and natural environment respectively. Bacteria count obtained after 0, 30, 60, 90, 120, 180, 240 and 300 minutes at room temperature and chill condition was taken and compared with their initial count. The amount of live bacteria drops by several orders of magnitude, to zero, on metallic copper and brass within 30 to 300 minutes in both room and chill conditions. In contrast, no reduction is seen in the number of colonies of live bacteria on plastics, ceramic and stainless steel in both room and chill conditions. These results suggest that the selection of metallic copper and brass for touch surfaces in hospitals, surfaces exposed to fruit processing and household utensils can materially assist in reducing bacterial contamination, which should lead to a reduction in the transmission of infectious organisms.
基金supported by the National Natural Science Foundation of China(52222407).
文摘Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.
基金National Natural Science Foundation of China,Grant/Award Number:52271200Scientific and Technological Innovation Foundation of Foshan,Grant/Award Number:BK20BE009+1 种基金the Fundamental Research Funds for the Central Universities,Grant/Award Number:FRF-TP-18-079A1Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2020A1515110460,ORCID:http://orcid.org/0000-0002-0870-2248。
文摘Electrocatalytic water splitting seems to be an efficient strategy to deal with increasingly serious environmental problems and energy crises but still suffers from the lack of stable and efficient electrocatalysts.Designing practical electrocatalysts by introducing defect engineering,such as hybrid structure,surface vacancies,functional modification,and structural distortions,is proven to be a dependable solution for fabricating electrocatalysts with high catalytic activities,robust stability,and good practicability.This review is an overview of some relevant reports about the effects of defect engineering on the electrocatalytic water splitting performance of electrocatalysts.In detail,the types of defects,the preparation and characterization methods,and catalytic performances of electrocatalysts are presented,emphasizing the effects of the introduced defects on the electronic structures of electrocatalysts and the optimization of the intermediates'adsorption energy throughout the review.Finally,the existing challenges and personal perspectives of possible strategies for enhancing the catalytic performances of electrocatalysts are proposed.An in-depth understanding of the effects of defect engineering on the catalytic performance of electrocatalysts will light the way to design high-efficiency electrocatalysts for water splitting and other possible applications.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(NRF-2020R1A6A1A03043435 and 2020R1A2C1099862)supported by the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korean Government(MOTIE)(P0012451,The Competency Development Program for Industry Specialist)。
文摘MXenes,the most recent addition to the 2D material family,have attracted significant attention owing to their distinctive characteristics,including high surface area,conductivity,surface characteristics,mechanical strength,etc.This review begins by presenting MXenes,providing insights into their structural characteristics,synthesis methods,and surface functional groups.The review covers a thorough analysis of MXene surface properties,including surface chemistry and termination group impacts.The properties of MXenes are influenced by their synthesis,which can be fluorine-based or fluorinedependent.Fluorine-based synthesis techniques involve etching with fluorine-based reagents,mainly including HF or LiF/HCl,while fluorine-free methods include electrochemical etching,chemical vapor deposition(CVD),alkaline etching,Lewis acid-based etching,etc.These techniques result in the emergence of functional groups such as-F,-O,-OH,-Cl,etc.on the MXenes surface,depending on the synthesis method used.Properties of MXenes,such as electrical conductivity,electronic properties,catalytic activity,magnetic properties,mechanical strength,and chemical and thermal stability,are examined,and the role of functional groups in determining these properties is explored.The review delves into the diverse applications of MXenes,encompassing supercapacitors,battery materials,hydrogen storage,fuel cells,electromagnetic interference(EMI) shielding,pollutant removal,water purification,flexible electronics,sensors,additive manufacturing,catalysis,biomedical and healthcare fields,etc.Finally,this article outlines the challenges and opportunities in the current and future development of MXenes research,addressing various aspects such as synthesis scalability,etching challenges,and multifunctionality,and exploring novel applications.The review concludes with future prospects and conclusions envisioning the impact of MXenes on future technologies and innovation.
基金Funded by the Jiangsu Province Industry-University-Research Cooperation Project (No.BY2018314)the Scientific Research Foundation of Jiangsu University of Technology (No.KYY18030)Jiangsu Overseas Visiting Scholar Program for University Prominent Young&Middle-aged Teachers and Presidents。
文摘3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal route.The as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spectroscopy (EDS),scanning electron microscopy (SEM) and Raman.SEM images of the samples reveal that the hierarchical flowerlike WS_(2) microspheres with diameters of about 3-5μm are composed of a number of curled nanosheets.Electrochemical tests such as charge/discharge,cyclic voltammetry,cycle life and rate performance were carried out on the WS_(2) sample.As an anode material for lithium-ion batteries,hierarchical flowerlike WS_(2) microspheres show excellent electrochemical performance.At a current density of100 mA·g^(-1),a high specific capacity of 647.8 mA·h·g^(-1) was achieved after 120 discharge/charge cycles.The excellent electrochemical performance of WS_(2) as an anode material for lithium-ion batteries can be attributed to its special 3D hierarchical structure.
基金supported by the National Key R&D Program of China(2023YFB4603504)the International Science&Technology Innovation Cooperation Project of Sichuan Province(2024YFHZ0232)+2 种基金the International Science&Technology Cooperation Project of Chengdu(2021-GH03-00009-HZ)the Program for Featured Directions of Engineering Multi-disciplines of Sichuan University(2020SCUNG203)the Program of Innovative Research Team for Young Scientists of Sichuan Province(22CXTD0019).
文摘The new-generation electronic components require a balance between electromagnetic interference shielding efficiency and open structure factors such as ventilation and heat dissipation.In addition,realizing the tunable shielding of porous shields over a wide range of wavelengths is even more challenging.In this study,the well-prepared thermoplastic polyurethane/carbon nanotubes composites were used to fabricate the novel periodic porous flexible metamaterials using fused deposition modeling 3D printing.Particularly,the investigation focuses on optimization of pore geometry,size,dislocation configuration and material thickness,thus establishing a clear correlation between structural parameters and shielding property.Both experimental and simulation results have validated the superior shielding performance of hexagon derived honeycomb structure over other designs,and proposed the failure shielding size(D_(f)≈λ/8-λ/5)and critical inclined angle(θf≈43°-48°),which could be used as new benchmarks for tunable electromagnetic shielding.In addition,the proper regulation of the material thickness could remarkably enhance the maximum shielding capability(85-95 dB)and absorption coefficient A(over 0.83).The final innovative design of the porous shielding box also exhibits good shielding effectiveness across a broad frequency range(over 2.4 GHz),opening up novel pathways for individualized and diversified shielding solutions.
基金supported by the National Natural Science Foundation of China(Grant Nos.52373280,52177014,51977009,52273257).
文摘With the diversified development of big data,detection and precision guidance technologies,electromagnetic(EM)functional materials and devices serving multiple spectrums have become a hot topic.Exploring the multispectral response of materials is a challenging and meaningful scientific question.In this study,MXene/TiO_(2)hybrids with tunable conduction loss and polarization relaxation are fabricated by in situ atomic reconstruction engineering.More importantly,MXene/TiO_(2)hybrids exhibit adjustable spectral responses in the GHz,infrared and visible spectrums,and several EM devices are constructed based on this.An antenna array provides excellent EM energy harvesting in multiple microwave bands,with|S11|up to−63.2 dB,and can be tuned by the degree of bending.An ultra-wideband bandpass filter realizes a passband of about 5.4 GHz and effectively suppresses the transmission of EM signals in the stopband.An infrared stealth device has an emissivity of less than 0.2 in the infrared spectrum at wavelengths of 6-14μm.This work can provide new inspiration for the design and development of multifunctional,multi-spectrum EM devices.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52161135302,22105087)the Postdoctoral Research Foundation of China(Grant No.2022M721360)the Natural Science Foundation of Jiangsu Province(Grant No.BK20210446)。
文摘The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in electrochemical acetonitrile reduction reaction(ARR)to date.Herein,we successfully realize the structural transformation of Pd Cu metallic aerogels(MAs)from face-centered cubic(FCC)to body-centered cubic(BCC)through annealing treatment.Specifically,the BCC Pd Cu MAs exhibit excellent ARR performance with high ethylamine selectivity of 90.91%,Faradaic efficiency of 88.60%,yield rate of 316.0 mmol h^(-1)g^(-1)_(Pd+Cu)and long-term stability for consecutive electrolysis within 20 h at-0.55 V vs.reversible hydrogen electrode,outperforming than those of FCC Pd Cu MAs.Under the membrane electrode assembly system,BCC Pd Cu MAs also demonstrate excellent ethylamine yield rate of 389.5 mmol h^(-1)g^(-1)_(Pd+Cu).Density functional theory calculation reveals that the d-d orbital coupling in BCC Pd Cu MAs results in an evident correlation effect for the interaction of Pd and Cu sites,which boosts up the Cu sites electronic activities to enhance ARR performance.Our work opens a new route to develop efficient ARR electrocatalysts from the perspective of crystalline structure transformation.
基金National Natural Science Foundation of China,Grant/Award Number:22102079Taishan Scholar Program of Shandong Province,China,Grant/Award Number:tsqn202211162Natural Science Foundation of Shandong Province of China,Grant/Award Numbers:ZR2021YQ10,ZR2022QB163。
文摘Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,but seldom do they exhibit excellent selectivity toward formate.In this article,we demonstrate that a heterointerface catalyst ZnO/ZnSnO3 with nanosheet morphology shows enhanced selectivity with a maximum Faradaic efficiency(FE)of 86%at−0.9 V versus reversible hydrogen electrode and larger current density for the conversion of CO_(2) to formate than pristine ZnO and ZnSnO3.In particular,the FEs of the C1 products(CO+HCOO−)exceed 98%over the potential window.The experimental measurements combined with theoretical calculations revealed that the ZnO in ZnO/ZnSnO3 heterojunction delivers the valence electron depletion and accordingly optimizes Zn d-band center,which results in moderate Zn-O hybridization of HCOO*and weakened Zn-C hybridization of competing COOH*,thus greatly boosting the HCOOH generation.Our study highlights the importance of charge redistribution in catalysts on the selectivity of electrochemical CO_(2) reduction.
基金supported by grants from the National Key Research and Development Program of China(2022YFB3806000)the National Natural Science Foundation of China(52325208 and 11974203)the Beijing Municipal Science and Technology Project(Z191100004819002).
文摘Metalenses with achromatic performance offer a new opportunity for high-quality imaging with an ultracompact configuration;however,they suffer from complex fabrication processes and low focusing efficiency.In this study,we propose an efficient design method for achromatic microlenses on a wavelength scale using materials with low dispersion,an adequately designed convex surface,and a thickness profile distribution.By taking into account the absolute chromatic aberration,relative focal length shift(FLS),and numerical aperture(NA),microlens with a certain focal length can be realized through our realized map of geometric features.Accordingly,the designed achromatic microlenses with low-dispersion fused silica were fabricated using a focused ion beam,and precise surface profiles were obtained.The fabricated microlenses exhibited a high average focusing efficiency of 65%at visible wavelengths of 410-680 nm and excellent achromatic capability via white light imaging.Moreover,the design exhibited the advantages of being polarization-insensitive and near-diffraction-limited.These results demonstrate the effectiveness of our proposed achromatic microlens design approach,which expands the prospects of miniaturized optics such as virtual and augmented reality,ultracompact microscopes,and biological endoscopy.
基金supported by the National Natural Science Foundation of China(Nos.12175231 and 11805131),Anhui Natural Science Foundation of China(No.2108085J05)Projects of International Cooperation and Exchanges NSFC(No.51111140389)the Collaborative Innovation Program of the Hefei Science Center,CAS(Nos.2021HSC-CIP020 and 2022HSCCIP009).
文摘Ferritic/martensitic(F/M)steel is widely used as a structural material in thermal and nuclear power plants.However,it is susceptible to intergranular damage,which is a critical issue,under service conditions.In this study,to improve the resistance to intergranular damage of F/M steel,a thermomechanical process(TMP)was employed to achieve a grain boundary engineering(GBE)microstructure in F/M steel P92.The TMP,including cold-rolling thickness reduction of 6%,9%,and 12%,followed by austenitization at 1323 K for 40 min and tempering at 1053 K for 45 min,was applied to the as-received(AR)P92 steel.The prior austenite grain(PAG)size,prior austenite grain boundary character distribution(GBCD),and connectivity of prior austenite grain boundaries(PAGBs)were investigated.Compared to the AR specimen,the PAG size did not change significantly.The fraction of coincident site lattice boundaries(CSLBs,3≤Σ≤29)and Σ3^(n) boundaries along PAGBs decreased with increasing reduction ratio because the recrystallization fraction increased with increasing reduction ratio.The PAGB connectivity of the 6%deformed specimen slightly deteriorated compared with that of the AR specimen.Moreover,potentiodynamic polarization studies revealed that the intergranular damage resistance of the studied steel could be improved by increasing the fraction of CSLBs along the PAGBs,indicating that the TMP,which involves low deformation,could enhance the intergranular damage resistance.
基金supported by the National Key R&D Program(2022YFE0206400)the National Natural Science Foundation of China(52202256)+4 种基金the Natural Science Foundation of Jiangsu Province of China(BK20220612)the Science and Technology Development Fund,Macao SAR(0096/2020/A2,0013/2021/AMJ,and 0082/2022/A2)the Opening Project of the Key Laboratory of Jiangsu Province for Silk Engineering,Soochow University(KJS2277)the funds from Jiangsu University“Qinglan Project”the Young Elite Scientists Sponsorship Program of the Jiangsu Association for Science and Technology
文摘Solid-state lithium batteries(SSLBs)with high safety have emerged to meet the increasing energy density demands of electric vehicles,hybrid electric vehicles,and portable electronic devices.However,the dendrite formation,high interfacial resistance,and deleterious interfacial reactions caused by solid-solid contact between electrode and electrolyte have hindered the commercialization of SSLBs.Thus,in this review,the state-of-the-art developments in the rational design of solid-state electrolyte and their progression toward practical applications are reviewed.First,the origin of interface instability and the sluggish charge carrier transportation in solid-solid interface are presented.Second,various strategies toward stabilizing interfacial stability(reducing interfacial resistance,suppressing lithium dendrites,and side reactions)are summarized from the physical and chemical perspective,including building protective layer,constructing 3D and gradient structures,etc.Finally,the remaining challenges and future development trends of solidstate electrolyte are prospected.This review provides a deep insight into solving the interfacial instability issues and promising solutions to enable practical high-energy-density lithium metal batteries.
基金supported by the National Research Foundation of Korea(NRF-2021R1A2C1008272)supported by the Institute of Information&communications Technology Planning&Evaluation(IITP)grant funded by the Korean government(MSIT)(No.2021-0-00259,Development of a Fast Wireless Charging System for Portable Terminals with improved heat dissipation and shielding performance)supported by the Applied Basic Research Program of Changzhou City(CJ20220030).
文摘Lithium-sulfur(Li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low cost.However,the development of high-energy density Li-S batteries with high loading of flammable sulfur faces the challenges of electrochemical performance degradation owing to the shuttle effect and safety issues related to fire or explosion accidents.In this work,we report a three-dimensional(3D)conductive nitrogen-doped carbon foam supported electrostatic self-assembled MXene-ammonium polyphosphate(NCF-MXene-APP)layer as a heat-resistant,thermally-insulated,flame-retardant,and freestanding host for Li-S batteries with a facile and costeffective synthesis method.Consequently,through the use of NCF-MXene-APP hosts that strongly anchor polysulfides,the Li-S batteries demonstrate outstanding electrochemical properties,including a high initial discharge capacity of 1191.6 mA h g^(-1),excellent rate capacity of 755.0 mA h g^(-1)at 1 C,and long-term cycling stability with an extremely low-capacity decay rate of 0.12%per cycle at 2 C.More importantly,these batteries can continue to operate reliably under high temperature or flame attack conditions.Thus,this study provides valuable insights into the design of safe high-performance Li-S batteries.
基金This study was supported by the National Nat-ural Science Foundation of China(No.22379105)the Natural Sci-ence Foundation of Shanxi Province(Nos.20210302123110 and 202303021211059)the Open Fund Project of Ningxia Sinostar Display Material Co.,Ltd.
文摘Although doped hole-transport materials(HTMs)off er an effi ciency benefi t for perovskite solar cells(PSCs),they inevi-tably diminish the stability.Here,we describe the use of various chlorinated small molecules,specifi cally fl uorenone-triphenylamine(FO-TPA)-x-Cl[x=para,meta,and ortho(p,m,and o)],with diff erent chlorine-substituent positions,as dopant-free HTMs for PSCs.These chlorinated molecules feature a symmetrical donor-acceptor-donor structure and ideal intramolecular charge transfer properties,allowing for self-doping and the establishment of built-in potentials for improving charge extraction.Highly effi cient hole-transfer interfaces are constructed between perovskites and these HTMs by strategi-cally modifying the chlorine substitution.Thus,the chlorinated HTM-derived inverted PSCs exhibited superior effi ciencies and air stabilities.Importantly,the dopant-free HTM FO-TPA-o-Cl not only attains a power conversion effi ciency of 20.82% but also demonstrates exceptional stability,retaining 93.8%of its initial effi ciency even after a 30-day aging test conducted under ambient air conditions in PSCs without encapsulation.These fi ndings underscore the critical role of chlorine-substituent regulation in HTMs in ensuring the formation and maintenance of effi cient and stable PSCs.
文摘The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> (OH)<sub>2</sub>, Li<sub>2</sub>CO<sub>3</sub> as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi<sub>0.4985</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> Mg<sub>0.0015</sub>O<sub>2</sub> cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm<sup>3</sup>. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.
基金supported by Nano·Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2022M3H4A1A04076667)
文摘Bi_(2)Te_(3)-based materials have drawn much attention from the thermoelectric community due to their excellent thermoelectric performance near room temperature.However,the stability of existing n-type Bi_(2)(Te,Se)_(3)materials is still low due to the evaporation energy of Se(37.70 kJ mol^(-1))being much lower than that of Te(52.55 kJ mol^(-1)).The evaporated Se from the material causes problems in interconnects of the module while degrading the efficiency.Here,we have developed a new approach for the high-performance and stable n-type Se-free Bi_(2)Te_(3)-based materials bymaximizing the electronic transport while suppressing the phonon transport,at the same time.Spontaneously generated FeTe_(2)nanoinclusions within the matrix during the melt-spinning and subsequent spark plasma sintering is the key to simultaneous engineering of the power factor and lattice thermal conductivity.The nanoinclusions change the fermi level of the matrix while intensifying the phonon scattering via nanoparticles.With a fine-tuning of the fermi level with Cu doping in the n-type Bi_(2)Te_(3)-0.02FeTe_(2),a high power factor of∼41×10^(-4)Wm^(-1)K^(-2)with an average zT of 1.01 at the temperature range 300-470 K are achieved,which are comparable to those obtained in n-type Bi_(2)(Te,Se)_(3)materials.The proposed approach enables the fabrication of high-performance n-type Bi_(2)Te_(3)-based materials without having to include volatile Se element,which guarantees the stability of the material.Consequently,widespread application of thermoelectric devices utilizing the n-type Bi_(2)Te_(3)-based materials will become possible.