Photocatalytic CO_(2)reduction is a promising route toward carbon neutrality,yet its practical application is hindered by the high activation energy barrier of v,rapid recombination of photo-generated electrons,and po...Photocatalytic CO_(2)reduction is a promising route toward carbon neutrality,yet its practical application is hindered by the high activation energy barrier of v,rapid recombination of photo-generated electrons,and poor product selectivity of traditional catalysts.Frustrated Lewis pairs(FLPs),which feature spatially separated Lewis acid and base sites,have recently emerged as a novel strategy to overcome these limitations.This review systematically examines the progress in FLPs-based photocatalytic systems.We focus on the construction stra-tegies for FLPs active sites,the optimization of charge carrier dynamics,and the synergistic electron transfer mechanisms with photoactive components.Central theme is the elucidation of microscopic mechanisms gov-erning CO_(2)activation,key intermediate conversion,and the efficient utilization of photogenerated electrons.By synthesizing current knowledge and outlining future prospects,this review aims to provide a theoretical framework that guides the rational design of highly active and selective catalysts for solar-driven CO_(2)reduction.展开更多
O3-types layered cathode materials in sodium-ion batteries(SIBs)suffer from the obvious lattice distortion induced by the complex phase transitions during Na^(+)intercalation/deintercalation process,leading to severe ...O3-types layered cathode materials in sodium-ion batteries(SIBs)suffer from the obvious lattice distortion induced by the complex phase transitions during Na^(+)intercalation/deintercalation process,leading to severe structural collapse and performance degradation.Herein,a series of high valence tantalum(Ta^(5+))doped Na(Ni_(0.4)Fe_(0.2)Mn_(0.4))_(1−x)Ta_(x)O_(2)(x=0/0.0025/0.005/0.01)secondary spherical particles are firstly developed,where Ta^(5+)doping enables the refined primary grain with a tightly stacked rod-like morphology.Comprehensive structural analysis via Neutron powder diffraction(NPD)and Synchrotron radiation X-ray diffraction(SXRD)reveals an expanded NaO_(2)slab and a reduction in Na site vacancy.The potential charge compensation mechanism is further illustrated by X-ray absorption spectroscopy(XAS)and X-ray photoelectron spectroscopy(XPS),unveiling a partial reduction from Ni^(3+)to Ni^(2+)with Ta^(5+)doping.In situ X-ray diffraction(in situ XRD)suggests that the decorated sample undergoes a volume change as low as 0.8%,in contrast with the pristine one(1.5%).Thus,the optimized sample with x=0.005 retains an enhanced capacity retention up to 70.4%at 1 C after 300 cycles in half-cell and delivers a high energy density of 251 Wh kg^(-1)(0.1 C)and with a good capacity retention of 81.0%at 1 C after 200 cycles in full-cell.Our findings provide new insights into the mechanism of high valence Ta^(5+)doping in stabilizing layered oxides cathode materials for SIBs.展开更多
Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most impor...Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most important cathode materials of ZIB.In this paper,α-Mn2O3 used as cathode of ZIB is synthesized via Metal-Organic Framework(MOF)-derived method,which delivers a high specific capacity of225 mAh g^(-1) at 0.05 A g^(-1) and 92.7 mAh g^(-1) after 1700 cycles at 2 A g^(-1).The charge storage mechanism of α-Mn2O3 cathode is found to greatly depend on the discharge current density.At lower current density discharging,the H+ and Zn2+ are successively intercalated into the α-Mn2O3 before and after the "turning point" of discharge voltage and their discharging products present obviously different morphologies changing from flower-like to large plate-like products.At a higher current density,the low-voltage plateau after the turning point disappears due to the decrease of amount of Zn2+ intercalation and the H+intercalation is dominated in α-Mn2 O3.This study provides significant understanding for future design and research of high-performance Mn-based cathodes of ZIB.展开更多
Though secondary aqueous Zn ion batteries(AZIBs)have been received broad concern in recent years,the development of suitable cathode materials of AZIBs is still a big challenge.The MnO_(2) has been deemed as one of mo...Though secondary aqueous Zn ion batteries(AZIBs)have been received broad concern in recent years,the development of suitable cathode materials of AZIBs is still a big challenge.The MnO_(2) has been deemed as one of most hopeful cathode materials of AZIBs on account of some extraordinary merits,such as richly natural resources,low toxicity,high discharge potential,and large theoretical capacity.However,the crystal structure diversity of MnO_(2) results in an obvious various of charge storage mechanisms,which can cause great differences in electrochemical performance.Furthermore,several challenges,including intrinsic poor conductivity,dissolution of manganese and sluggish ion transport dynamics should be conquered before real practice.This work focuses on the reaction mechanisms and recent progress of MnO_(2)-based materials of AZIBs.In this review,a detailed review of the reaction mechanisms and optimal ways for enhancing electrochemical performance for MnO_(2)-based materials is proposed.At last,a number of viewpoints on challenges,future development direction,and foreground of MnO_(2)-based materials of aqueous zinc ions batteries are put forward.This review clarifies reaction mechanism of MnO_(2)-based materials of AZIBs,and offers a new perspective for the future invention in MnO_(2)-based cathode materials,thus accelerate the extensive development and commercialization practice of aqueous zinc ions batteries.展开更多
Molybdenum oxide(MoO_(3)), with superior features of multi-electrochemical states, high theoretical capacitance, and low cost, is a desirable supercapacitor electrode material but suffers from low conductivity and ins...Molybdenum oxide(MoO_(3)), with superior features of multi-electrochemical states, high theoretical capacitance, and low cost, is a desirable supercapacitor electrode material but suffers from low conductivity and insufficient active sites. The MoO_(3) capacitance can be largely amplified by introducing oxygen(O) vacancies, but the mechanisms at the atomic scale are still ambiguous.Herein, O vacancies are created at the O2 and O3 sites in the MoO_(3) nanobelts by carbonization to maximize the supercapacitance in the MoO_(2.39). The supercapacitive storage is mainly ascribed to the proton adsorption at the O1 sites to create Mo–OH, leading to an expansion of the interlayer spacing along the lattice B-axis. Roughly 98% of the initial supercapacitance is retained after 1000 cycles,due to the reversible change in the interlayer spacing. Our results provide an insight into the oxygen deficiency-related mechanisms of the supercapacitive performance at the atomic scale and devise a facile method to enhance the supercapacitance for energy storage and conversion.展开更多
Potassium ion capacitors(PICs)are regarded as promising large-scale aqueous energy storage systems.However,due to the poor K^(+)transport kinetics and the structural instability of the cathode materials,the key issues...Potassium ion capacitors(PICs)are regarded as promising large-scale aqueous energy storage systems.However,due to the poor K^(+)transport kinetics and the structural instability of the cathode materials,the key issues of limited energy density and poor cyclic stability are obstacles to the in-depth growth of PICs.Herein,a novel O-doped perovskite fluoride is demonstrated via an in-situ electrochemical oxidation strategy as the cathode for PICs,introducing additional defects that improve the capacitance and facilitate the reaction kinetics of the electrode.During the electrochemical oxidation process,it is discovered that the perovskite fluoride crystal tends to transform into disordered O-doped KMnF 3(K_(x)MnF_(y)O_(z)),realizing a structural reconstruction at the electrode material/electrolyte interface.The First-principles calculations based on density functional theory(DFT)are performed to confirm that the improved electrical conduc-tivity and low ionic adsorption energy may be ascribed to the substitution of oxygen for fluorine.The obtained K_(1.14)MnF_(1.17)O_(1.26) cathode achieves a high specific capacitance of 694 F g^(-1) at 1 A g^(-1),as well as high capacitance retention of 91.3%after 10,000 charge/discharge cycles in mild K_(2)SO_(4) electrolyte.This study provides an effective strategy to improve the capacitive performance of perovskite fluoride cathode materials in electrochemical energy storage.展开更多
Transition metal fluorides(TMFs)cathode materials have shown extraordinary promises for electrochemical energy storage,but the understanding of their electrochemical reaction mechanisms is still a matter of debate due...Transition metal fluorides(TMFs)cathode materials have shown extraordinary promises for electrochemical energy storage,but the understanding of their electrochemical reaction mechanisms is still a matter of debate due to the complicated and continuous changing in the battery internal environment.Here,we design a novel iron fluoride(FeF_(2))aggregate assembled with cylindrical nanoparticles as cathode material to build FeF_(2) lithium-ion batteries(LIBs)and employ advanced in situ magnetometry to detect their intrinsic electronic structure during cycling in real time.The results show that FeF_(2) cannot be involved in complete conversion reactions when the FeF_(2) LIBs operate between the conventional voltage range of 1.0–4.0 V,and that the corresponding conversion ratio of FeF_(2) can be further estimated.Importantly,we first demonstrate that the spin-polarized surface capacitance exists in the FeF_(2) cathode by monitoring the magnetic responses over various voltage ranges.The research presents an original and insightful method to examine the conversion mechanism of TMFs and significantly provides an important reference for the future artificial design of energy systems based on spinpolarized surface capacitance.展开更多
Rechargeable magnesium-ion batteries(MIBs) are favorable substitutes for conventional lithium-ion batteries(LIBs) because of abundant magnesium reserves, a high theoretical energy density, and great inherent safety. O...Rechargeable magnesium-ion batteries(MIBs) are favorable substitutes for conventional lithium-ion batteries(LIBs) because of abundant magnesium reserves, a high theoretical energy density, and great inherent safety. Organic electrode materials with excellent structural tunability,unique coordination reaction mechanisms, and environmental friendliness offer great potential to promote the electrochemical performance of MIBs. However, research on organic magnesium battery cathode materials is still preliminary with many significant challenges to be resolved including low electrical conductivity and unwanted but severe dissolution in useful electrolytes. Herein, we provide a detailed overview of reported organic cathode materials for MIBs. We begin with basic properties such as charge storage mechanisms(e.g., n-, p-, and bipolartype), moving to recent advances in various types of organic cathodes including carbonyl-, nitrogen-, and sulfur-based materials. To shed light on the diverse strategies targeting high-performance Mg-organic batteries, elaborate summaries of various approaches are presented.Generally, these strategies include molecular design, polymerization, mixing with carbon, nanosizing and electrolyte/separator optimization.This review provides insights on exploring high-performance organic cathodes in rechargeable MIBs.展开更多
Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn ...Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into d-MnO_(2) nanosheets irreversibly,thus results in a change of the reaction mechanism with Kþion intercalation.However,the low capacity has greatly limited its practical application.Herein,we found that the tetrahedrally-coordinated Co_(2) þions were leached when MnCo_(2)_(4) was equilibrated in 1 mol L^(-1) HCl solution,leading to the formation of layered CoOOH on MnCo_(2)_(4) surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free Co_(6) octahedra.The as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion.In general,our work not only offers a feasible approach to deliberate modification of MnCo_(2)_(4)'s surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.展开更多
Fast charging and high-power delivering batteries are highly demanded in mobile electronics,electric vehicles and grid energy storage,but there are full of challenges.The star-material Li_(3)V_(2)(PO_(4))_(3) is demon...Fast charging and high-power delivering batteries are highly demanded in mobile electronics,electric vehicles and grid energy storage,but there are full of challenges.The star-material Li_(3)V_(2)(PO_(4))_(3) is demonstrated as a promising high-rate cathode material meeting the above requirements.Herein,we report the carbon decorated Li_(3)V_(2)(PO_(4))_(3) (LVP/C) cathode prepared via a facile method,which displays a remarkable high-rate capability and long-term cycling performance.Briefly,the prepared LVP/C delivers a high discharge capacity of 122 mAh g^(-1)(-93% of the theoretical capacity) at a high rate up to 20 C and a superior capacity retention of 87.1% after 1000 cycles.Importantly,by applying a combination of X-ray absorption spectroscopy and full-range mapping of resonant inelastic X-ray scattering,we clearly elucidate the structural and chemical evolutions of LVP upon various potentials and cycle numbers.We show unambiguous spectroscopic evidences that the evolution of the hybridization strength between V and O in LVP/C as a consequence of lithiation/delithiation is highly reversible both in the bulk and on the surface during the discharge-charge processes even over extended cycles,which should be responsible for the remarkable electrochemical performance of LVP/C.Our present study provides not only an effective synthesis strategy but also deeper insights into the surface and bulk electrochemical reaction mechanism of LVP,which should be beneficial for the further design of high-performance LVP electrode materials.展开更多
The widely accepted theory concerning the electrochemical energy storage mechanism of copper hexacyanoferrate(CuHCF)for supercapacitors is that CuHCF stores charge by the reversible redox processes of Fe^3+/Fe2+couple...The widely accepted theory concerning the electrochemical energy storage mechanism of copper hexacyanoferrate(CuHCF)for supercapacitors is that CuHCF stores charge by the reversible redox processes of Fe^3+/Fe2+couple and Cu cations are electrochemically inactive.In this work,CuHCF nanocubes(CuHCF-NC)were synthesized in the presence of potassium citrate and its electrochemical properties were tentatively studied in 1 mol/L Na2 SO4 aqueous electrolyte.Good supercapacitive performance was exhibited.The combined analyses of cyclic voltammogram(CV)and X-ray photoelectron spectroscopy(XPS)disclosed that the CuHCF nanocubes underwent the redox reactions of Fe^3+/Fe2+and Cu^2+/Cu+couples to store charges.The Cu^2+/Cu+redox couple was activated due to the strong coordination interaction between the carboxylate groups of citrate ions and surface Cu cations.展开更多
Photocatalytic hydrogen evolution from water splitting is an appealing method for producing clean chemical fuels.Cu_(2)O,with a suitable bandgap,holds promise as a semiconductor for this process.However,the strong pho...Photocatalytic hydrogen evolution from water splitting is an appealing method for producing clean chemical fuels.Cu_(2)O,with a suitable bandgap,holds promise as a semiconductor for this process.However,the strong photo-corrosion and rapid charge recombination of Cu_(2)O strongly limit its application in the photocatalytic fields.Herein,an S-scheme heterojunction photocatalyst composed of TiO_(2)and Cu_(2)O was rationally designed to effectively avoid the photo-corrosion of Cu_(2)O.The introduction of an interfacial nitrogen-doped carbon(NC)layer switches the heterojunction interfacial charge transfer pathway from the p-n to S-scheme heterojunction,which avoids excessive accumulation of photogenerated holes on the surface of Cu_(2)O.Meanwhile,the hybrid structure shows a broad spectral response(300-800 nm)and efficient charge separation and transfer efficiency.Interestingly,the highest photocatalytic hydrogen evolution rate of TiO_(2)-NC-3%Cu_(2)O-3%Ni is 13521.9μmol g^(-1)h^(-1),which is approximately 664.1 times higher than that of pure Cu_(2)O.In-situ X-ray photoelectron spectroscopy and Kelvin probe confirm the charge transfer mechanism of S-scheme heterojunction.The formation of S-scheme heterojunctions effectively accelerates the separation of photogenerated electron-hole pairs and enhances redox capacity,thereby improving the photocatalytic performance and stability of Cu_(2)O.This study provides valuable insights into the rational design of highly efficient Cu_(2)O-based heterojunction photocatalysts for hydrogen production.展开更多
Computational modeling methods,including molecular dynamics(MD)and Monte Carlo(MC)simulations,and density functional theory(DFT),are receiving booming interests for exploring charge storage mechanisms of electrochemic...Computational modeling methods,including molecular dynamics(MD)and Monte Carlo(MC)simulations,and density functional theory(DFT),are receiving booming interests for exploring charge storage mechanisms of electrochemical energy storage devices.These methods can effectively be used to obtain molecular scale local information or provide clear explanations for novel experimental findings that cannot be directly interpreted through experimental investigations.This short review is dedicated to emphasizing recent advances in computational simulation methods for exploring the charge storage mechanisms in typical nanoscale materials,such as nanoporous carbon materials,2 D MXene materials,and metal-organic framework electrodes.Beyond a better understanding of charge storage mechanisms and experimental observations,fast and accurate enough models would be helpful to provide theoretical guidance and experimental basis for the design of new high-performance electrochemical energy storage devices.展开更多
In recent years,haze has posed a serious threat to the global climate change,ecological balance and human health.In this study,the laboratory experiments and field observations were performed and a possible charging m...In recent years,haze has posed a serious threat to the global climate change,ecological balance and human health.In this study,the laboratory experiments and field observations were performed and a possible charging mechanism was proposed to investigate the space charge properties in haze events.The laboratory experiments showed that the charge polarity of primary aerosol is determined by species of combustion fuels while the magnitude is dependent on the combustion completeness.The field observations revealed that the space charge of atmosphere aerosol in haze events differs from that of fair weather and is closely related to PM2.5 concentration when Relative Humidity(RH)<60%,with 1 to 2 orders of magnitude less than the case when RH≥60%.The analysis of equivalent chargeto-mass ratio(ECTM)suggested that in haze events the space charge is governed by primary aerosol emitted by combustion of fossil fuel in a low relative humidity,whereas it is manipulated by the secondary chemical reaction of atmosphere aerosol in a high relative humidity.And we can identify the main pollutants in haze events according to the polarity of atmosphere aerosol and quickly take measures when RH<60%.Accordingly,the dusthaze of RH<80% can be divided into dry-dust-haze when RH<60%and wet-dust-haze when 60%≤RH<80%.Our study firstly elucidated the space charge properties of atmosphere aerosol in haze events and can provide a new perspective for the prevention and control of air pollution.展开更多
Owing to high electrical conductivity and ability to reversibly host a variety of inserted ions,2D metallic molybdenum disulfide(1 T-MoS_(2))has demonstrated promising energy storage performance when used as a superca...Owing to high electrical conductivity and ability to reversibly host a variety of inserted ions,2D metallic molybdenum disulfide(1 T-MoS_(2))has demonstrated promising energy storage performance when used as a supercapacitor electrode.However,its charge storage mechanism is still not fully understood,in particular,how the interlayer spacing of 1 T-MoS_(2)would affect its capacitive performance.In this work,molecular dynamics simulations of 1 T-MoS_(2)with interlayer spacing ranging from 0.615 to 1.615 nm have been performed to investigate the resulting charge storage capacity in ionic liquids.Simulations reveal a camel-like capacitance-potential relation,and MoS_(2)with an interlayer spacing of 1.115 nm has the highest volumetric and gravimetric capacitance of118 F cm^(-3)and 42 F g^(-1),respectively.Although ions in MoS_(2)with an interlayer spacing of 1.115 nm diffuse much faster than with interlayer spacings of 1.365 and 1.615 nm,the MoS_(2)with larger interlayer spacing has a much faster-charging process.Our analyses reveal that the ion number density and its charging speed,as well as ion motion paths,have significant impacts on the charging response.This work helps to understand how the interlayer spacing affects the interlayer ion structures and the capacitive performance of MoS_(2),which is important for revealing the charge storage mechanism and designing MoS_(2)supercapacitor.展开更多
The pursuit of high-performance electrode materials is highly desired to meet the demand of batteries with high energy and power density.However,a deep understanding of the charge storage mechanism is always challengi...The pursuit of high-performance electrode materials is highly desired to meet the demand of batteries with high energy and power density.However,a deep understanding of the charge storage mechanism is always challenging,which limits the development of advanced electrode materials.Herein,high-resolution mass spectroscopy(HR-MS)is employed to detect the evolution of organic electrode materials during the redox process and reveal the charge storage mechanism,by using small molecular oxamides as an example,which have ortho-carbonyls and are therefore potential electrochemical active materials for batteries.The HR-MS results adequately proved that the oxamides could reversibly store lithium ions in the voltage window of 1.5–3.8 V.Upon deeper reduction,the oxamides would decompose due to the cleavage of the C–N bonds in oxamide structures,which could be proved by the fragments detected by HR-MS,^(1)H NMR,and the generation of NH_(3)after the reduction of oxamide by Li.This work provides a strategy to deeply understand the charge storage mechanism of organic electrode materials and will stimulate the further development of characterization techniques to reveal the charge storage mechanism for developing high-performance electrode materials.展开更多
The linear shaped charge cutting technology is an effective technology for aircraft separation.It can separate invalid components from aircrafts timely to achieve light-weight.Magnesium alloy is the lightest metal mat...The linear shaped charge cutting technology is an effective technology for aircraft separation.It can separate invalid components from aircrafts timely to achieve light-weight.Magnesium alloy is the lightest metal material,and can be used to cast effective light-weight components of an aircraft construction.However,the application study of the linear shaped charge cutting technology on magnesium alloy components is basically blank.In response to the demand for the linear separation of magnesium alloys,the Mg-12Gd-0.5Y-0.4Zn alloy is selected to carry out the target shaped charge cutting test.The effects of the shaped charge line density,cutting thickness,and mechanical properties on the cutting performance of the alloy are studied.The shaped charge cutting mechanism is analyzed through the notch structure.The results show that the linear shaped charge cutting performance is significantly affected by the penetration and the collapse.The higher the linear density is,the stronger the ability of the linear shaped charge cutter is,and the greater the penetration depth is,which is advantageous.However,the target structure will be damaged when it is too large(e.g.,4.5 g·m^(-1)).Within 12 mm,when the cutting thickness of the target increases,the penetration depth increases.The lower the tensile strength is,the greater the penetration depth is,and the more conducive the penetration depth to the shaped charge cutting is.When the elongation(EL)increases to 12%,the collapse of the target is incomplete and the target cannot be separated.When the tensile strength of the Mg-Gd-Y-Zn alloy is less than 350 MPa,the EL is less than 6.5%,the cutting thickness is less than 12 mm,and the linear shaped charge cutting of the magnesium alloy can be achieved stably.展开更多
With the boom in electric vehicles(EVs),there is an increasing demand for high-performance lithium-ion batteries.Lithium manganese iron phosphate(LMFP)has emerged as an enhanced variation of LiFePO4(LFP),offering an e...With the boom in electric vehicles(EVs),there is an increasing demand for high-performance lithium-ion batteries.Lithium manganese iron phosphate(LMFP)has emerged as an enhanced variation of LiFePO4(LFP),offering an energy density 10%–20%greater than that of LFP.Structural distortion caused by the Jahn–Teller effect decreases the capacity and voltage platform,thus restricting the commercialization of this material.Herein,ideas to overcome these challenges,including the crystal structure of LMFP and strategies to mitigate the Jahn–Teller distortion,are first explored.Then,the migration pathways of Li+during charging and discharging and the phase transition mechanisms that affect the material’s performance are discussed.Next,the optimal Mn:Fe ratio for achieving the desired performance is described.The influences of various synthesis and modification methods on the morphology and structure of LMFP are reviewed.Additionally,different modification techniques,such as doping and coating,to enhance the performance of LMFP are highlighted.Finally,an overview of the current state of research on the recycling and reuse of LMFP is provided.By addressing these key topics,this paper offers a theoretical foundation for the further development of LMFP,thus contributing to its eventual commercialization.展开更多
Hydrogen peroxide(H_(2)O_(2)),as an essential and green chemical,is extensively used in energy and environmental applications.However,the production of H_(2)O_(2)primarily relies on the anthraquinone method,which is a...Hydrogen peroxide(H_(2)O_(2)),as an essential and green chemical,is extensively used in energy and environmental applications.However,the production of H_(2)O_(2)primarily relies on the anthraquinone method,which is an energy-intensive method involving multi-step reactions,producing harmful by-product wastes.Solar-driven H_(2)O_(2)production,an alternative route for H_(2)O_(2)generation,is a green and sustainable technology since it only utilizes water and oxygen as feedstock.However,the rapid recombination of charge carriers as well as insufficient redox capability limit the photocatalytic H_(2)O_(2)production performance.Constructing step-scheme(S-scheme)heterojunction photocatalysts has been regarded as an effective strategy to address these drawbacks because it not only achieves spatially separated charge carriers,but also preserves redox capability of the photocatalytic system.This paper covers the recent advances of S-scheme heterojunction photocatalysts for H_(2)O_(2)production in terms of basic principles,characterization techniques,and preparation strategies.Moreover,the mechanism and advantages of S-scheme heterojunction for photocatalytic H_(2)O_(2)generation are systematically discussed.The recent S-scheme heterojunction designs,including inorganic-organic heterojunction,inorganic-inorganic heterojunction,and organic-organic heterojunction,are summarized.Lastly,the challenges and research directions of S-scheme photocatalysts for H_(2)O_(2)generation are presented.展开更多
Photocatalysis is a green and environmentally-friendly process that utilizes the ubiquitous intermittent sunlight.To date,an emerging S-scheme heterojunction across the intimately coupled heterojunction materials is p...Photocatalysis is a green and environmentally-friendly process that utilizes the ubiquitous intermittent sunlight.To date,an emerging S-scheme heterojunction across the intimately coupled heterojunction materials is proposed to surpass the efficiency of conventional Ⅱ-type and Z-type photocatalysis.Further-more,S-scheme heterojunction photocatalysts with greatly improved photocatalytic performance have gained significant attention due to their fast charge carriers separation along with strong redox ability and stability,since its proposal in 2019.Herein,a timely and comprehensive review is highly desired to cover the state-of-the-art advances.Driven by this idea,the review conveys the recent progress and provides new insights into further developments.Unlike the conventional method,in this review,we im-plement a quantification model to outline current trends in S-scheme heterojunctions research as well as their correlations.The overview begins with the fundamentals of four basic photocatalytic mechanisms,followed by its design principles.Afterward,diverse characterization techniques used in the S-scheme heterojunctions are systematically summarized along with the modification strategies to boost photocat-alytic performances.Additionally,the internal reaction mechanism and emerging applications have been reviewed,including water conversion,CO_(2) remediation,wastewater treatment,H_(2)0_(2) production,N_(2) fix-ation,etc.To sum up the review,we present several current challenges and future prospects of the S-scheme heterojunctions photocatalysts,aiming to provide indispensable platforms for the future smart design of photocatalysts.展开更多
基金the National Natural Science Foundation of China(22278190)Qing Lan Project of Jiangsu Province(2023)+1 种基金Open Project of State Key Laboratory of Structural Chemistry(20230022)Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment.
文摘Photocatalytic CO_(2)reduction is a promising route toward carbon neutrality,yet its practical application is hindered by the high activation energy barrier of v,rapid recombination of photo-generated electrons,and poor product selectivity of traditional catalysts.Frustrated Lewis pairs(FLPs),which feature spatially separated Lewis acid and base sites,have recently emerged as a novel strategy to overcome these limitations.This review systematically examines the progress in FLPs-based photocatalytic systems.We focus on the construction stra-tegies for FLPs active sites,the optimization of charge carrier dynamics,and the synergistic electron transfer mechanisms with photoactive components.Central theme is the elucidation of microscopic mechanisms gov-erning CO_(2)activation,key intermediate conversion,and the efficient utilization of photogenerated electrons.By synthesizing current knowledge and outlining future prospects,this review aims to provide a theoretical framework that guides the rational design of highly active and selective catalysts for solar-driven CO_(2)reduction.
基金supported by the National Natural Science Foundation of China (52402298, 52172224, 52202228, 22479112)the Science and Technology Correspondent Project of Tianjin(24YDTPJC00240)+3 种基金Science Research Project of Hebei Education Department (BJK2022011)Central Funds Guiding the Local Science and Technology Development of Hebei Province (236Z4404G)the Beijing Tianjin Hebei Basic Research Cooperation Special Project(E2024202273)Tianjin Sci.&Tech. Program (22YFYSHZ00220)
文摘O3-types layered cathode materials in sodium-ion batteries(SIBs)suffer from the obvious lattice distortion induced by the complex phase transitions during Na^(+)intercalation/deintercalation process,leading to severe structural collapse and performance degradation.Herein,a series of high valence tantalum(Ta^(5+))doped Na(Ni_(0.4)Fe_(0.2)Mn_(0.4))_(1−x)Ta_(x)O_(2)(x=0/0.0025/0.005/0.01)secondary spherical particles are firstly developed,where Ta^(5+)doping enables the refined primary grain with a tightly stacked rod-like morphology.Comprehensive structural analysis via Neutron powder diffraction(NPD)and Synchrotron radiation X-ray diffraction(SXRD)reveals an expanded NaO_(2)slab and a reduction in Na site vacancy.The potential charge compensation mechanism is further illustrated by X-ray absorption spectroscopy(XAS)and X-ray photoelectron spectroscopy(XPS),unveiling a partial reduction from Ni^(3+)to Ni^(2+)with Ta^(5+)doping.In situ X-ray diffraction(in situ XRD)suggests that the decorated sample undergoes a volume change as low as 0.8%,in contrast with the pristine one(1.5%).Thus,the optimized sample with x=0.005 retains an enhanced capacity retention up to 70.4%at 1 C after 300 cycles in half-cell and delivers a high energy density of 251 Wh kg^(-1)(0.1 C)and with a good capacity retention of 81.0%at 1 C after 200 cycles in full-cell.Our findings provide new insights into the mechanism of high valence Ta^(5+)doping in stabilizing layered oxides cathode materials for SIBs.
基金supported by the National Natural Science Foundation of China (51672156)Local Innovative Research Teams Project of Guangdong Pearl River Talents Program (No. 2017BT01N111)+2 种基金Guangdong Province Technical Plan Project (2017B010119001)Shenzhen Technical Plan Project (JCYJ20170817161221958 and JCYJ20170412170706047)Shenzhen Graphene Manufacturing Innovation Center (201901161513)。
文摘Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most important cathode materials of ZIB.In this paper,α-Mn2O3 used as cathode of ZIB is synthesized via Metal-Organic Framework(MOF)-derived method,which delivers a high specific capacity of225 mAh g^(-1) at 0.05 A g^(-1) and 92.7 mAh g^(-1) after 1700 cycles at 2 A g^(-1).The charge storage mechanism of α-Mn2O3 cathode is found to greatly depend on the discharge current density.At lower current density discharging,the H+ and Zn2+ are successively intercalated into the α-Mn2O3 before and after the "turning point" of discharge voltage and their discharging products present obviously different morphologies changing from flower-like to large plate-like products.At a higher current density,the low-voltage plateau after the turning point disappears due to the decrease of amount of Zn2+ intercalation and the H+intercalation is dominated in α-Mn2 O3.This study provides significant understanding for future design and research of high-performance Mn-based cathodes of ZIB.
基金supported by the National Natural Science Foundation of China(U1960107)the Natural Science Foundation of Hebei Province(E2022501014)+4 种基金the"333"Talent Project of Hebei Province(A202005018)the Fundamental Research Funds for the Central Universities(N2123001)the Science and Technology Research Youth Fund Project of Higher Education Institutions of Hebei Province(QN2022196)the 2023 Hebei Provincial Postgraduate Student Innovation Ability training funding project(CXZZSS2023196)the Performance subsidy fund for Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province(22567627H)。
文摘Though secondary aqueous Zn ion batteries(AZIBs)have been received broad concern in recent years,the development of suitable cathode materials of AZIBs is still a big challenge.The MnO_(2) has been deemed as one of most hopeful cathode materials of AZIBs on account of some extraordinary merits,such as richly natural resources,low toxicity,high discharge potential,and large theoretical capacity.However,the crystal structure diversity of MnO_(2) results in an obvious various of charge storage mechanisms,which can cause great differences in electrochemical performance.Furthermore,several challenges,including intrinsic poor conductivity,dissolution of manganese and sluggish ion transport dynamics should be conquered before real practice.This work focuses on the reaction mechanisms and recent progress of MnO_(2)-based materials of AZIBs.In this review,a detailed review of the reaction mechanisms and optimal ways for enhancing electrochemical performance for MnO_(2)-based materials is proposed.At last,a number of viewpoints on challenges,future development direction,and foreground of MnO_(2)-based materials of aqueous zinc ions batteries are put forward.This review clarifies reaction mechanism of MnO_(2)-based materials of AZIBs,and offers a new perspective for the future invention in MnO_(2)-based cathode materials,thus accelerate the extensive development and commercialization practice of aqueous zinc ions batteries.
基金financially supported by the Hong Kong Baptist University(No.RMGS-2019-1-03A)。
文摘Molybdenum oxide(MoO_(3)), with superior features of multi-electrochemical states, high theoretical capacitance, and low cost, is a desirable supercapacitor electrode material but suffers from low conductivity and insufficient active sites. The MoO_(3) capacitance can be largely amplified by introducing oxygen(O) vacancies, but the mechanisms at the atomic scale are still ambiguous.Herein, O vacancies are created at the O2 and O3 sites in the MoO_(3) nanobelts by carbonization to maximize the supercapacitance in the MoO_(2.39). The supercapacitive storage is mainly ascribed to the proton adsorption at the O1 sites to create Mo–OH, leading to an expansion of the interlayer spacing along the lattice B-axis. Roughly 98% of the initial supercapacitance is retained after 1000 cycles,due to the reversible change in the interlayer spacing. Our results provide an insight into the oxygen deficiency-related mechanisms of the supercapacitive performance at the atomic scale and devise a facile method to enhance the supercapacitance for energy storage and conversion.
基金the financial support from Liaoning Sci-ence and Technology Development Foundation Guided by Cen-tral Government(No.2021JH6/10500139)the Fundamental Research Funds for the Central Universities(No.N2205003)+2 种基金the financial support from the National Natural Science Foundation of China(No.52003007)Nat-ural Science Foundation of Hebei Province(No.E2019409063)Langfang top-notch talent(No.LFBJ202004).
文摘Potassium ion capacitors(PICs)are regarded as promising large-scale aqueous energy storage systems.However,due to the poor K^(+)transport kinetics and the structural instability of the cathode materials,the key issues of limited energy density and poor cyclic stability are obstacles to the in-depth growth of PICs.Herein,a novel O-doped perovskite fluoride is demonstrated via an in-situ electrochemical oxidation strategy as the cathode for PICs,introducing additional defects that improve the capacitance and facilitate the reaction kinetics of the electrode.During the electrochemical oxidation process,it is discovered that the perovskite fluoride crystal tends to transform into disordered O-doped KMnF 3(K_(x)MnF_(y)O_(z)),realizing a structural reconstruction at the electrode material/electrolyte interface.The First-principles calculations based on density functional theory(DFT)are performed to confirm that the improved electrical conduc-tivity and low ionic adsorption energy may be ascribed to the substitution of oxygen for fluorine.The obtained K_(1.14)MnF_(1.17)O_(1.26) cathode achieves a high specific capacitance of 694 F g^(-1) at 1 A g^(-1),as well as high capacitance retention of 91.3%after 10,000 charge/discharge cycles in mild K_(2)SO_(4) electrolyte.This study provides an effective strategy to improve the capacitive performance of perovskite fluoride cathode materials in electrochemical energy storage.
基金National Natural Science Foundation of China,Grant/Award Number:51804173。
文摘Transition metal fluorides(TMFs)cathode materials have shown extraordinary promises for electrochemical energy storage,but the understanding of their electrochemical reaction mechanisms is still a matter of debate due to the complicated and continuous changing in the battery internal environment.Here,we design a novel iron fluoride(FeF_(2))aggregate assembled with cylindrical nanoparticles as cathode material to build FeF_(2) lithium-ion batteries(LIBs)and employ advanced in situ magnetometry to detect their intrinsic electronic structure during cycling in real time.The results show that FeF_(2) cannot be involved in complete conversion reactions when the FeF_(2) LIBs operate between the conventional voltage range of 1.0–4.0 V,and that the corresponding conversion ratio of FeF_(2) can be further estimated.Importantly,we first demonstrate that the spin-polarized surface capacitance exists in the FeF_(2) cathode by monitoring the magnetic responses over various voltage ranges.The research presents an original and insightful method to examine the conversion mechanism of TMFs and significantly provides an important reference for the future artificial design of energy systems based on spinpolarized surface capacitance.
基金the support from the National Key Research & Development Program (2022YFB3803700) of ChinaNational Natural Science Foundation (No.52171186)the support from the Center of Hydrogen Science,Shanghai Jiao Tong University。
文摘Rechargeable magnesium-ion batteries(MIBs) are favorable substitutes for conventional lithium-ion batteries(LIBs) because of abundant magnesium reserves, a high theoretical energy density, and great inherent safety. Organic electrode materials with excellent structural tunability,unique coordination reaction mechanisms, and environmental friendliness offer great potential to promote the electrochemical performance of MIBs. However, research on organic magnesium battery cathode materials is still preliminary with many significant challenges to be resolved including low electrical conductivity and unwanted but severe dissolution in useful electrolytes. Herein, we provide a detailed overview of reported organic cathode materials for MIBs. We begin with basic properties such as charge storage mechanisms(e.g., n-, p-, and bipolartype), moving to recent advances in various types of organic cathodes including carbonyl-, nitrogen-, and sulfur-based materials. To shed light on the diverse strategies targeting high-performance Mg-organic batteries, elaborate summaries of various approaches are presented.Generally, these strategies include molecular design, polymerization, mixing with carbon, nanosizing and electrolyte/separator optimization.This review provides insights on exploring high-performance organic cathodes in rechargeable MIBs.
基金supported by the National Key Research and Development Program of China(2022YFE0206300)the National Natural Science Foundation of China(22209047,U21A2081,22075074)+2 种基金Natural Science Foundation of Hunan Province(2020JJ5035)Hunan Provincial Department of Education Outstanding Youth Project(23B0037)Macao Science and Technology Development Fund(Macao SAR,FDCT-0096/2020/A2).
文摘Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into d-MnO_(2) nanosheets irreversibly,thus results in a change of the reaction mechanism with Kþion intercalation.However,the low capacity has greatly limited its practical application.Herein,we found that the tetrahedrally-coordinated Co_(2) þions were leached when MnCo_(2)_(4) was equilibrated in 1 mol L^(-1) HCl solution,leading to the formation of layered CoOOH on MnCo_(2)_(4) surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free Co_(6) octahedra.The as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion.In general,our work not only offers a feasible approach to deliberate modification of MnCo_(2)_(4)'s surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.
基金supported by Collaborative Innovation Center of Suzhou Nano Science & Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)+5 种基金the 111 roject, Joint International Research Laboratory of Carbon-Based Functional Materials and Devicesthe National Natural Science Foundation of China (11905154)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (19KJA550004)the Natural Science Foundation of Jiangsu Province (BK20190814)the National Key R&D Program of China (No. 2016YFA0202600)supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231。
文摘Fast charging and high-power delivering batteries are highly demanded in mobile electronics,electric vehicles and grid energy storage,but there are full of challenges.The star-material Li_(3)V_(2)(PO_(4))_(3) is demonstrated as a promising high-rate cathode material meeting the above requirements.Herein,we report the carbon decorated Li_(3)V_(2)(PO_(4))_(3) (LVP/C) cathode prepared via a facile method,which displays a remarkable high-rate capability and long-term cycling performance.Briefly,the prepared LVP/C delivers a high discharge capacity of 122 mAh g^(-1)(-93% of the theoretical capacity) at a high rate up to 20 C and a superior capacity retention of 87.1% after 1000 cycles.Importantly,by applying a combination of X-ray absorption spectroscopy and full-range mapping of resonant inelastic X-ray scattering,we clearly elucidate the structural and chemical evolutions of LVP upon various potentials and cycle numbers.We show unambiguous spectroscopic evidences that the evolution of the hybridization strength between V and O in LVP/C as a consequence of lithiation/delithiation is highly reversible both in the bulk and on the surface during the discharge-charge processes even over extended cycles,which should be responsible for the remarkable electrochemical performance of LVP/C.Our present study provides not only an effective synthesis strategy but also deeper insights into the surface and bulk electrochemical reaction mechanism of LVP,which should be beneficial for the further design of high-performance LVP electrode materials.
基金supported by the National Natural Science Foundation of China(No.51877029)。
文摘The widely accepted theory concerning the electrochemical energy storage mechanism of copper hexacyanoferrate(CuHCF)for supercapacitors is that CuHCF stores charge by the reversible redox processes of Fe^3+/Fe2+couple and Cu cations are electrochemically inactive.In this work,CuHCF nanocubes(CuHCF-NC)were synthesized in the presence of potassium citrate and its electrochemical properties were tentatively studied in 1 mol/L Na2 SO4 aqueous electrolyte.Good supercapacitive performance was exhibited.The combined analyses of cyclic voltammogram(CV)and X-ray photoelectron spectroscopy(XPS)disclosed that the CuHCF nanocubes underwent the redox reactions of Fe^3+/Fe2+and Cu^2+/Cu+couples to store charges.The Cu^2+/Cu+redox couple was activated due to the strong coordination interaction between the carboxylate groups of citrate ions and surface Cu cations.
基金X.Li thanks the National Natural Science Foundation of China(Nos.21975084 and 51672089)the Natural Science Foundation of Guangdong Province(No.2021A1515010075)for their support.X.Peng thanks the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF21028)for the support.
文摘Photocatalytic hydrogen evolution from water splitting is an appealing method for producing clean chemical fuels.Cu_(2)O,with a suitable bandgap,holds promise as a semiconductor for this process.However,the strong photo-corrosion and rapid charge recombination of Cu_(2)O strongly limit its application in the photocatalytic fields.Herein,an S-scheme heterojunction photocatalyst composed of TiO_(2)and Cu_(2)O was rationally designed to effectively avoid the photo-corrosion of Cu_(2)O.The introduction of an interfacial nitrogen-doped carbon(NC)layer switches the heterojunction interfacial charge transfer pathway from the p-n to S-scheme heterojunction,which avoids excessive accumulation of photogenerated holes on the surface of Cu_(2)O.Meanwhile,the hybrid structure shows a broad spectral response(300-800 nm)and efficient charge separation and transfer efficiency.Interestingly,the highest photocatalytic hydrogen evolution rate of TiO_(2)-NC-3%Cu_(2)O-3%Ni is 13521.9μmol g^(-1)h^(-1),which is approximately 664.1 times higher than that of pure Cu_(2)O.In-situ X-ray photoelectron spectroscopy and Kelvin probe confirm the charge transfer mechanism of S-scheme heterojunction.The formation of S-scheme heterojunctions effectively accelerates the separation of photogenerated electron-hole pairs and enhances redox capacity,thereby improving the photocatalytic performance and stability of Cu_(2)O.This study provides valuable insights into the rational design of highly efficient Cu_(2)O-based heterojunction photocatalysts for hydrogen production.
基金funding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation program(grant agreement no.714581)supported by the Fundamental Research Funds for the Central Universities(No.YJ201886)+1 种基金the National Natural Science Foundation of China(No.501902215)Sichuan Science and Technology Program(No.2020ZDZX0005)
文摘Computational modeling methods,including molecular dynamics(MD)and Monte Carlo(MC)simulations,and density functional theory(DFT),are receiving booming interests for exploring charge storage mechanisms of electrochemical energy storage devices.These methods can effectively be used to obtain molecular scale local information or provide clear explanations for novel experimental findings that cannot be directly interpreted through experimental investigations.This short review is dedicated to emphasizing recent advances in computational simulation methods for exploring the charge storage mechanisms in typical nanoscale materials,such as nanoporous carbon materials,2 D MXene materials,and metal-organic framework electrodes.Beyond a better understanding of charge storage mechanisms and experimental observations,fast and accurate enough models would be helpful to provide theoretical guidance and experimental basis for the design of new high-performance electrochemical energy storage devices.
基金supported by a grant from the National Natural Science Foundation of China(Nos.11490551)
文摘In recent years,haze has posed a serious threat to the global climate change,ecological balance and human health.In this study,the laboratory experiments and field observations were performed and a possible charging mechanism was proposed to investigate the space charge properties in haze events.The laboratory experiments showed that the charge polarity of primary aerosol is determined by species of combustion fuels while the magnitude is dependent on the combustion completeness.The field observations revealed that the space charge of atmosphere aerosol in haze events differs from that of fair weather and is closely related to PM2.5 concentration when Relative Humidity(RH)<60%,with 1 to 2 orders of magnitude less than the case when RH≥60%.The analysis of equivalent chargeto-mass ratio(ECTM)suggested that in haze events the space charge is governed by primary aerosol emitted by combustion of fossil fuel in a low relative humidity,whereas it is manipulated by the secondary chemical reaction of atmosphere aerosol in a high relative humidity.And we can identify the main pollutants in haze events according to the polarity of atmosphere aerosol and quickly take measures when RH<60%.Accordingly,the dusthaze of RH<80% can be divided into dry-dust-haze when RH<60%and wet-dust-haze when 60%≤RH<80%.Our study firstly elucidated the space charge properties of atmosphere aerosol in haze events and can provide a new perspective for the prevention and control of air pollution.
基金the financial support from the National Natural Science Foundation of China(51876072)the Hubei Provincial Natural Science Foundation of China(2019CFA002,2020CFA093)+1 种基金Sichuan Science and Technology Program(2019YFG0457)the support from the National Energy Research Scientific Computing Center,a DOE Office of Science User Facility supported by the Office of Science of the U.S.Department of Energy under Contract No.DE-AC0205CH11231
文摘Owing to high electrical conductivity and ability to reversibly host a variety of inserted ions,2D metallic molybdenum disulfide(1 T-MoS_(2))has demonstrated promising energy storage performance when used as a supercapacitor electrode.However,its charge storage mechanism is still not fully understood,in particular,how the interlayer spacing of 1 T-MoS_(2)would affect its capacitive performance.In this work,molecular dynamics simulations of 1 T-MoS_(2)with interlayer spacing ranging from 0.615 to 1.615 nm have been performed to investigate the resulting charge storage capacity in ionic liquids.Simulations reveal a camel-like capacitance-potential relation,and MoS_(2)with an interlayer spacing of 1.115 nm has the highest volumetric and gravimetric capacitance of118 F cm^(-3)and 42 F g^(-1),respectively.Although ions in MoS_(2)with an interlayer spacing of 1.115 nm diffuse much faster than with interlayer spacings of 1.365 and 1.615 nm,the MoS_(2)with larger interlayer spacing has a much faster-charging process.Our analyses reveal that the ion number density and its charging speed,as well as ion motion paths,have significant impacts on the charging response.This work helps to understand how the interlayer spacing affects the interlayer ion structures and the capacitive performance of MoS_(2),which is important for revealing the charge storage mechanism and designing MoS_(2)supercapacitor.
基金financialy supported by the National Natural Science Foundation of China(52173163,22279038,and 22205069)the National 1000-Talents Program,the Innovation Fund of WNLO,the Open Fund of the State Key Laboratory of Integrated Optoelectronics(IOSKL2020KF02)+1 种基金Wenzhou Science&Technology Bureau(ZG2022020,G20220022,and G20220026)the China Postdoctoral Science Foundation(2021TQ0115,2021 M701302,and 2020 M672323)
文摘The pursuit of high-performance electrode materials is highly desired to meet the demand of batteries with high energy and power density.However,a deep understanding of the charge storage mechanism is always challenging,which limits the development of advanced electrode materials.Herein,high-resolution mass spectroscopy(HR-MS)is employed to detect the evolution of organic electrode materials during the redox process and reveal the charge storage mechanism,by using small molecular oxamides as an example,which have ortho-carbonyls and are therefore potential electrochemical active materials for batteries.The HR-MS results adequately proved that the oxamides could reversibly store lithium ions in the voltage window of 1.5–3.8 V.Upon deeper reduction,the oxamides would decompose due to the cleavage of the C–N bonds in oxamide structures,which could be proved by the fragments detected by HR-MS,^(1)H NMR,and the generation of NH_(3)after the reduction of oxamide by Li.This work provides a strategy to deeply understand the charge storage mechanism of organic electrode materials and will stimulate the further development of characterization techniques to reveal the charge storage mechanism for developing high-performance electrode materials.
基金the National Natural Science Foundation of China(No.U2037601)。
文摘The linear shaped charge cutting technology is an effective technology for aircraft separation.It can separate invalid components from aircrafts timely to achieve light-weight.Magnesium alloy is the lightest metal material,and can be used to cast effective light-weight components of an aircraft construction.However,the application study of the linear shaped charge cutting technology on magnesium alloy components is basically blank.In response to the demand for the linear separation of magnesium alloys,the Mg-12Gd-0.5Y-0.4Zn alloy is selected to carry out the target shaped charge cutting test.The effects of the shaped charge line density,cutting thickness,and mechanical properties on the cutting performance of the alloy are studied.The shaped charge cutting mechanism is analyzed through the notch structure.The results show that the linear shaped charge cutting performance is significantly affected by the penetration and the collapse.The higher the linear density is,the stronger the ability of the linear shaped charge cutter is,and the greater the penetration depth is,which is advantageous.However,the target structure will be damaged when it is too large(e.g.,4.5 g·m^(-1)).Within 12 mm,when the cutting thickness of the target increases,the penetration depth increases.The lower the tensile strength is,the greater the penetration depth is,and the more conducive the penetration depth to the shaped charge cutting is.When the elongation(EL)increases to 12%,the collapse of the target is incomplete and the target cannot be separated.When the tensile strength of the Mg-Gd-Y-Zn alloy is less than 350 MPa,the EL is less than 6.5%,the cutting thickness is less than 12 mm,and the linear shaped charge cutting of the magnesium alloy can be achieved stably.
基金supported by National Natural Science Foundation of China(Grant Nos.52302293 and 22272110)Innovation Project of Education Department of Guangdong Province(Grant No.2023KTSCX124)+2 种基金Shenzhen Science and Technology Program(Grant No.KJZD2023092311460401)Guangdong Higher Education Letter(Grant No.[2024]No.30)Shenzhen Key Laboratory of Applied Technologies of Super-Diamond and Functional Crystals(Grant No.ZDSYS20230626091303007).
文摘With the boom in electric vehicles(EVs),there is an increasing demand for high-performance lithium-ion batteries.Lithium manganese iron phosphate(LMFP)has emerged as an enhanced variation of LiFePO4(LFP),offering an energy density 10%–20%greater than that of LFP.Structural distortion caused by the Jahn–Teller effect decreases the capacity and voltage platform,thus restricting the commercialization of this material.Herein,ideas to overcome these challenges,including the crystal structure of LMFP and strategies to mitigate the Jahn–Teller distortion,are first explored.Then,the migration pathways of Li+during charging and discharging and the phase transition mechanisms that affect the material’s performance are discussed.Next,the optimal Mn:Fe ratio for achieving the desired performance is described.The influences of various synthesis and modification methods on the morphology and structure of LMFP are reviewed.Additionally,different modification techniques,such as doping and coating,to enhance the performance of LMFP are highlighted.Finally,an overview of the current state of research on the recycling and reuse of LMFP is provided.By addressing these key topics,this paper offers a theoretical foundation for the further development of LMFP,thus contributing to its eventual commercialization.
文摘Hydrogen peroxide(H_(2)O_(2)),as an essential and green chemical,is extensively used in energy and environmental applications.However,the production of H_(2)O_(2)primarily relies on the anthraquinone method,which is an energy-intensive method involving multi-step reactions,producing harmful by-product wastes.Solar-driven H_(2)O_(2)production,an alternative route for H_(2)O_(2)generation,is a green and sustainable technology since it only utilizes water and oxygen as feedstock.However,the rapid recombination of charge carriers as well as insufficient redox capability limit the photocatalytic H_(2)O_(2)production performance.Constructing step-scheme(S-scheme)heterojunction photocatalysts has been regarded as an effective strategy to address these drawbacks because it not only achieves spatially separated charge carriers,but also preserves redox capability of the photocatalytic system.This paper covers the recent advances of S-scheme heterojunction photocatalysts for H_(2)O_(2)production in terms of basic principles,characterization techniques,and preparation strategies.Moreover,the mechanism and advantages of S-scheme heterojunction for photocatalytic H_(2)O_(2)generation are systematically discussed.The recent S-scheme heterojunction designs,including inorganic-organic heterojunction,inorganic-inorganic heterojunction,and organic-organic heterojunction,are summarized.Lastly,the challenges and research directions of S-scheme photocatalysts for H_(2)O_(2)generation are presented.
基金National Natural Science Foundation of China(Grant No.62004143)Key R&D Program of Hubei Province(Grant No.2022BAA084).
文摘Photocatalysis is a green and environmentally-friendly process that utilizes the ubiquitous intermittent sunlight.To date,an emerging S-scheme heterojunction across the intimately coupled heterojunction materials is proposed to surpass the efficiency of conventional Ⅱ-type and Z-type photocatalysis.Further-more,S-scheme heterojunction photocatalysts with greatly improved photocatalytic performance have gained significant attention due to their fast charge carriers separation along with strong redox ability and stability,since its proposal in 2019.Herein,a timely and comprehensive review is highly desired to cover the state-of-the-art advances.Driven by this idea,the review conveys the recent progress and provides new insights into further developments.Unlike the conventional method,in this review,we im-plement a quantification model to outline current trends in S-scheme heterojunctions research as well as their correlations.The overview begins with the fundamentals of four basic photocatalytic mechanisms,followed by its design principles.Afterward,diverse characterization techniques used in the S-scheme heterojunctions are systematically summarized along with the modification strategies to boost photocat-alytic performances.Additionally,the internal reaction mechanism and emerging applications have been reviewed,including water conversion,CO_(2) remediation,wastewater treatment,H_(2)0_(2) production,N_(2) fix-ation,etc.To sum up the review,we present several current challenges and future prospects of the S-scheme heterojunctions photocatalysts,aiming to provide indispensable platforms for the future smart design of photocatalysts.
