CO_(2)hydrogenation is an attractive way to store and utilize carbon dioxide generated by industrial processes,as well as to produce valuable chemicals from renewable and abundant resources.Iron catalysts are commonly...CO_(2)hydrogenation is an attractive way to store and utilize carbon dioxide generated by industrial processes,as well as to produce valuable chemicals from renewable and abundant resources.Iron catalysts are commonly used for the hydrogenation of carbon oxides to hydrocarbons.Iron-molybdenum catalysts have found numerous applications in catalysis,but have been never evaluated in the CO_(2)hydrogenation.In this work,the structural properties of iron-molybdenum catalysts without and with a promoting alkali metal(Li,Na,K,Rb,or Cs)were characterized using X-ray diffraction,hydrogen temperatureprogrammed reduction,CO_(2)temperature-programmed desorption,in-situ^(57)Fe Mossbauer spectroscopy and operando X-ray adsorption spectroscopy.Their catalytic performance was evaluated in the CO_(2)hydrogenation.During the reaction conditions,the catalysts undergo the formation of an iron(Ⅱ)molybdate structure,accompanied by a partial reduction of molybdenum and carbidization of iron.The rate of CO_(2)conversion and product selectivity strongly depend on the promoting alkali metals,and electronegativity was identified as an important factor affecting the catalytic performance.Higher CO_(2)conversion rates were observed with the promoters having higher electronegativity,while low electronegativity of alkali metals favors higher light olefin selectivity.展开更多
The ever-growing pursuit of high energy density batteries has triggered extensive efforts toward developing alkali metal(Li,Na,and K)battery(AMB)technologies owing to high theoretical capacities and low redox potentia...The ever-growing pursuit of high energy density batteries has triggered extensive efforts toward developing alkali metal(Li,Na,and K)battery(AMB)technologies owing to high theoretical capacities and low redox potentials of metallic anodes.Typically,for new battery systems,the electrolyte design is critical for realizing the battery electrochemistry of AMBs.Conventional electrolytes in alkali ion batteries are generally unsuitable for sustaining the stability owing to the hyper-reactivity and dendritic growth of alkali metals.In this review,we begin with the fundamentals of AMB electrolytes.Recent advancements in concentrated and fluorinated electrolytes,as well as functional electrolyte additives for boosting the stability of Li metal batteries,are summarized and discussed with a special focus on structure-composition-performance relationships.We then delve into the electrolyte formulations for Na-and K metal batteries,including those in which Na/K do not adhere to the Li-inherited paradigms.Finally,the challenges and the future research needs in advanced electrolytes for AMB are highlighted.This comprehensive review sheds light on the principles for the rational design of promising electrolytes and offers new inspirations for developing stable AMBs with high performance.展开更多
Alkali metal-carbon dioxide(Li/Na/K-CO_(2))batteries are emerging electrochemical energy storage technologies in the context of the energy crisis and the urgent demand for carbon neutrality.Alkali metal-CO_(2) batteri...Alkali metal-carbon dioxide(Li/Na/K-CO_(2))batteries are emerging electrochemical energy storage technologies in the context of the energy crisis and the urgent demand for carbon neutrality.Alkali metal-CO_(2) batteries offer a new strategy for CO_(2) fixation and utilization,and thus has been receiving considerable attention in recent years.Considerable progress has been achieved since alkali metal-CO_(2) batteries were invented,especially in terms of development of new electrode materials,and yet,research is lacking on the underlying mechanisms of the systems.This is the first typical review focusing on the electrochemical mechanisms of metal-CO_(2) batteries that summarizes the current understanding of and provides insights into the thermodynamic reaction pathways,the kinetic characteristics,and the crucial factors determining the reaction mechanisms in alkali metal-CO_(2) batteries.The review starts with the fundamental concepts of alkali metal-CO_(2) batteries,followed by a comprehensive discussion of the working mechanisms on cathodes and anodes.Moreover,the operation mechanisms of state-of-the-art electrolytes,including liquid and(quasi-)solid-state electrolytes,are also described.Finally,we identify the unsolved problems in current alkali metal-CO_(2) batteries and propose potential topics for future research.展开更多
Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transpo...Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transport kinetics of Li^(+)/Na^(+)/K^(+)in the 2×2 channels of a-MnO_(2)with a growth direction of[001]is revealed.We show that ion radius plays a decisive role in determining the ion transport and electrochemistry.Regardless of the ion radii,Li^(+)/Na^(+)/K^(+)can all go through the 2×2 channels of a-MnO_(2),generating large stress and causing channel merging or opening.However,smaller ions such as Li^(+)and Na^(+)cannot only transport along the[001]direction but also migrate along the<110>direction to the nanowire surface;for large ion such as K^(+),diffusion along the<110>direction is prohibited.The different ion transport behavior has grand consequences in the electrochemistry of metal oxygen batteries(MOBs).For Li-O_(2)battery,Li^(+)transports uniformly to the nanowire surface,forming a uniform layer of oxide;Na^(+)also transports to the nanowire surface but may be clogged locally due to its larger radius,therefore sporadic pearl-like oxides form on the nanowire surface;K^(+)cannot transport to the nanowire surface due to its large radius,instead,it breaks the nanowire locally,causing local deposition of potassium oxides.The study provides atomic scale understanding of the alkali metal ion transport mechanism which may be harnessed to improve the performance of MOBs.展开更多
Cobalt nanoparticles(NPs)catalysts are extensively used in heterogeneous catalytic reactions,and the addition of alkali metal promoters is a common method to modulate the catalytic performance because the catalyst'...Cobalt nanoparticles(NPs)catalysts are extensively used in heterogeneous catalytic reactions,and the addition of alkali metal promoters is a common method to modulate the catalytic performance because the catalyst's surface structures and morphologies are sensitive to the addition of promoters.However,the underlying modulation trend remains unclear.Herein,the adsorption of alkali metal promoters(Na and K)on the surfaces of face-centered-cubic(FCC)and hexagonal-closest packed(HCP)polymorphous cobalt was systematically investigated using density functional theory.Furthermore,the effect of alkali promoters on surface energies and nanoparticle morphologies was revealed on the basis of Wulff theory.For FCC-Co,the exposed area of the(111)facet in the nanoparticle increases with the adsorption coverage of alkali metal oxide.Meanwhile,the(311),(110),and(100)facets would disappear under the higher adsorption coverage of alkali metals.For HCPCo,the Wulff morphology is dominated by the(0001)and(1011)facets and is independent of the alkali metal adsorption coverage.This work provides insights into morphology modulation by alkali metal promoters for the rational design and synthesis of cobalt-based nanomaterials with desired facets and morphologies.展开更多
Bis(15-crown-5)-stilbenes containing crown ether parts have been widely used in a variety of chemical applications,such as cation detectors,because of their ability to selectively bind to alkali metal cations,Bis(15-c...Bis(15-crown-5)-stilbenes containing crown ether parts have been widely used in a variety of chemical applications,such as cation detectors,because of their ability to selectively bind to alkali metal cations,Bis(15-crown-5)-stilbenes and its derivatives with complexation of one-or two-alkali metal cation(Li^(+),Na^(+)and K^(+))have been theoretically investigat-ed by quantum chemistry methods.The coordination of alkali cations results in partial shrinkage of crown ethers,which directly affected natural distribution analysis charges and molecular orbital energy levels.The number of alkali metal ions has significant effects on absorption spectra and mean second hyperpolarizability.When one alkali metal ion was added to the anticonformer of bis(15-crown-5)-stilbene,the absorption spectra were obvious-ly redshifted and the mean second hyperpolarizability values were slightly increased;while two alkali metal ions were added to bis(15-crown-5)-stilbene,the absorption spectra were ob-viously blue shifted and the mean second hyperpolarizability values decreased.On the other hand,as the radius of the alkali ions increased,the mean second hyperpolarizability values of the compounds increased gradually.It is indicated that the mean second hyperpolarizability value is sensitive to the number and radius of the alkali metal cations,thus the third order nonlinear optical response can be used as a signal to detect the number and type of alkali met-al ions.展开更多
Rechargeable alkali metal-air batteries are considered as the most promising candidate for the power source of electric vehicles(EVs) due to their high energy density. However, the practical application of metal-air b...Rechargeable alkali metal-air batteries are considered as the most promising candidate for the power source of electric vehicles(EVs) due to their high energy density. However, the practical application of metal-air batteries is still challenging. In the past decade, many strategies have been purposed and explored, which promoted the development of metal-air batteries. The reaction mechanisms have been gradually clarified and catalysts have been rationally designed for air cathodes. In this review, we summarize the recent development of alkali metal-air batteries from four parts: metal anodes, electrolytes, air cathodes and reactant gases, wherein we highlight the important achievement in this filed. Finally problems and prospective are discussed towards the future development of alkali metal-air batteries.展开更多
EAB zeolite was successfully prepared and applied to selective adsorption of Li^(+),Na^(+)and K^(+)ions.The physical and chemical properties of the adsorbent were characterized by X-ray diffraction(XRD),X-ray fluoresc...EAB zeolite was successfully prepared and applied to selective adsorption of Li^(+),Na^(+)and K^(+)ions.The physical and chemical properties of the adsorbent were characterized by X-ray diffraction(XRD),X-ray fluorescence(XRF),scanning electron microscope(SEM)and thermogravimetry(TG)methods.The ion exchange behaviours for Li^(+),Na^(+)and K^(+)ions in monomcomponent and multicomponent solutions were studied.In independent ion exchange,the ion exchange capacities ratiosα(/Na/Li)andα(K/Li)were 3.8 and 6.2,respectively.In competitive ion exchange,the selectivitiesβ(Na/Li)andβ(K/Li)increased with the initial concentrations and reached 409 and 992 when the initial concentrations was 100 mmol/L.The thermodynamic study results showed that Gibbs free energy change(ΔGΘ)of ion exchange reaction between Li-EAB and K^(+)was-34.96 kJ/mol,indicating that ion exchange of K^(+)ions was more energetically favourable than Li^(+)ions.The calculation results showed that the energy barriers of ion exchange increased in the order K^(+)Na^(+)<Li^(+).The study shows that EAB zeolite is potential to be used in the separation of alkali ions.展开更多
Alkali metal ion batteries(AMIBs)are playing an irreplaceable part in the energy revolution,due to their intrinsic advantages of large capacity/power density and abundance of alkali metal ions in the earth’s crust.De...Alkali metal ion batteries(AMIBs)are playing an irreplaceable part in the energy revolution,due to their intrinsic advantages of large capacity/power density and abundance of alkali metal ions in the earth’s crust.Despite their great promise,the inborn deficiencies of commercial graphite and other anodes being researched so far call for the quest of better alternatives that exhibit all-round performance with the balance of energy/power density and cycling stability.Gallium-based materials,with impressive capacity utilization and self-healing ability,provide an anticipated solution to this conundrum.In this review,an overview on the recent progress of gallium-based anodes and their storage mechanism is presented.The current strategies used as engineering solutions to meet the scientific challenges ahead are discussed,in addition to the insightful outlook for possible future study.展开更多
In this paper, the interaction parameters in the subregular solution model, λ1 and λ2, are regarded as a linear function of temperature, T. Therefore, the molar excess Gibbs energy of A-B binary system may be reexpr...In this paper, the interaction parameters in the subregular solution model, λ1 and λ2, are regarded as a linear function of temperature, T. Therefore, the molar excess Gibbs energy of A-B binary system may be reexpressed as follows: GmE= xAxB[(λ11 +λ 12T) + (λ21 + λ22T)xB] The calculation of the model parameters. λ11 ,λ12, λ21 and λ22, was carried out numerically from the phase diagrams for 11 alkali metal-alkali halide or alkali earth metal-halide systems. In addition, artificial neural network trained by known data has been used to predict the values of these model parameters. The predicted results are in good agreement with the calculated ones. The applicability of the subregular solution model to the alkali metal-alkali halide or alkali earth metal-halide systems were tested by comparing the available experimental composition along the boundary of miscibility gap with the calculated ones which were obtained by using genetic algorithm. The good agreement between the calculated and experimental results across the entire liquidus is valid evidence in support of the model.展开更多
The catalytic effects of alkali metal ions(Na^(+)and K^(+))on NO_(x)precursor formation during coal pyrolysis were investigated using the N-containing compound pyridine as a model compound.Density functional theory ca...The catalytic effects of alkali metal ions(Na^(+)and K^(+))on NO_(x)precursor formation during coal pyrolysis were investigated using the N-containing compound pyridine as a model compound.Density functional theory calculations at the B3LYP/6-31G(d,p)level of theory were conducted to elucidate the mechanism of pyridine pyrolysis and the pathways for HCN formation.The calculation results indicate that Na^(+)and K^(+)have distinct influences on different pyrolysis reactions;these alkali metal ions facilitate the initial hydrogen transfer from C_(1)to N and C_(2),whereas they hinder the other hydrogen migration reactions.Both Na^(+)and K^(+)significantly reduce the activation energies for C–C bond breakage and triple-bond formation,whereas they increase the activation energies for the isomerization reactions.The different effects essentially result from the distinct charge distributions induced by the two ions.Due to the distinct influences on the different reactions,the rate-determining steps are modulated,affecting the competitiveness of the different possible pathways of HCN formation.The formation of HCN from pyridine is promoted in the presence of Na^(+)and K^(+)because all the overall activation energies are decreased for different pathways.The calculation results agree well with previous experimental studies.Thus,the findings offer a new and promising approach to reveal the formation mechanism of NO_(x)and facilitate the control of NO_(x)for coal utilization.展开更多
Based on the density functional theory calculations,we have investigated the feasibility of two-dimensionalβ-GeS monolayer as high-performance anodes for alkali metal ion batteries.The results show that the electrica...Based on the density functional theory calculations,we have investigated the feasibility of two-dimensionalβ-GeS monolayer as high-performance anodes for alkali metal ion batteries.The results show that the electrical conductivity of β-GeS monolayer can be enhanced after adsorbing the alkali metal atoms owing to the semiconductor-to-metal transition.The low diffusion barriers of alkali metal atoms on the β-GeS surface indicate a rapid charge/discharge rate without metal clustering.Moreover,the low average open-circuit voltage(0.211 V)and a high theoretical capacity(1024 mAh·g^(-1))for Na suggest that theβ-GeS monolayer is a promising anode material for Na-ion batteries with high performance.展开更多
Alloyed based anode materials with high theoretical specific capacity and low reaction potential are considered to be highly potential high-energy density anode materials for alkali metal ion batteries(AMIBs).Thus,the...Alloyed based anode materials with high theoretical specific capacity and low reaction potential are considered to be highly potential high-energy density anode materials for alkali metal ion batteries(AMIBs).Thus,the design of alloyed based materials with high electrochemical performance has attracted great attention.Among the numerous characterization methods for guiding electrode materials design,in situ transmission electron microscopy(TEM)gradually plays an irreplaceable role due to its high temporal and spatial resolution in directly observing the change of morphology,crystal structure and element evolutions.Herein,we reviewed the two current research hotspots and mainly focused on the structure design of alloyed based electrode material under the guidance of in situ TEM.Specifically,various nanostructure designs of alloyed based electrode materials with guidance of in situ TEM were employed to solve the key scientific issues of the violent volume change during alloying/dealloying processes for enhanced electrochemical performances.Mainly through introducing buffer space in the electrode material to reduce volume change to improve structural stability,including porous structure(0 D),nanotube structure(1 D),simple hollow structure,yolk-shell structure and some hybrid hollow structures(3 D).Furthermore,the direct guidance of in situ TEM is expected for creating new opportunities to nextgeneration electrode material design for AMIBs.展开更多
Sulfur dioxide(SO_(2))emissions from diesel exhaust pose a serious threat to the environment and human health.Thus,desulfurization technology and the performance of desulfurization materials must be improved.In this s...Sulfur dioxide(SO_(2))emissions from diesel exhaust pose a serious threat to the environment and human health.Thus,desulfurization technology and the performance of desulfurization materials must be improved.In this study,MnO_(2) was modified with various alkali metal ions using the impregnation method to enhance its SO_(2) capture performance.The composites were characterized intensively by scanning electron microscopy,energydispersive X-ray spectroscopy,X-ray diffraction spectroscopy,and Brunauer-Emmett-Teller theory.The SO_(2) capture performance of these composites were measured via thermogravimetry,and the effect of doping with alkali metal ions on the SO_(2) capture performance of MnO_(2) was investigated.Results showed that the SO_(2) capture performance of MnO_(2) could be enhanced by doping with alkali metal ions,and the MnO_(2) composite doped with LiOH(2.0 mol/L)had the best SO_(2) capture capacity(124 mgSO_(2)/gMaterial),which was 18%higher than that of pure MnO_(2).Moreover,the type and concentration of alkali metal ions had varying effects on the SO_(2) capture performance of MnO_(2).In our experiment,the SO_(2) capture performance of the MnO_(2) doped with NaOH,LiCl,Na2CO3,K2CO3,and Li2CO3 composites were worse than that of pure MnO_(2).Therefore,the influences of the type and concentration of alkali metal ions to be doped into desulfurization materials must be considered comprehensively.展开更多
In order to employ the waste heat effectively,a novel three-stage integrated system based upon a solid oxide fuel cell(SOFC),an alkali metal thermoelectric converter(AMTEC)and thermally regenerative electrochemical cy...In order to employ the waste heat effectively,a novel three-stage integrated system based upon a solid oxide fuel cell(SOFC),an alkali metal thermoelectric converter(AMTEC)and thermally regenerative electrochemical cycles(TRECs)is put forward.Considering the main electrochemically and thermodynamically irreversible losses,the power output and the efficiency of the subsystems and the integrated system are compared,and optimally operating regions for the current density,the power output,and the efficiency of the integrated system are explored.Calculations demonstrate that the maximum power density of the considered system is up to 7466 W/m2,which allows 18%and 74%higher than that of the conventional SOFC-AMTEC device and the stand-alone fuel cell model,respectively.It is proved that the considered system is an efficient approach to boost energy efficiency.Moreover,the influence of several significant parameters on the comprehensive performance of the integrated system is expounded in detail,including the electrolyte thickness of the SOFC,the leakage resistance of the SOFC,and the area ratio between the SOFC electrode and the AMTEC subsystem.展开更多
Metal-organic frameworks(MOFs) have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here,a typical metal-organic framework HKUST-1(also named Cu-BTC or MOF-199) was chemi...Metal-organic frameworks(MOFs) have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here,a typical metal-organic framework HKUST-1(also named Cu-BTC or MOF-199) was chemically reduced by doping it with alkali metals(Li, Na and K) and they were further used to investigate their CO2 adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction(XRD), thermo-gravimetric analysis(TGA)and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO2 storage capacity of HKUST-1 doped with moderate quantities of Li+, Na+and K+, individually, was greater than that of unmodified HKUST-1. The highest CO2 adsorption uptake of 8.64mmol/g was obtained with 1K-HKUST-1, and it was ca. 11% increase in adsorption capacity at 298 K and 18 bar as compared with HKUST-1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO2 than those of N2. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO2 after 10 cycles.展开更多
The electronic structures and field emission properties of capped CNT55 systems with or without alkali metal atom adsorption were systematically investigated by density functional theory calculation.The results indica...The electronic structures and field emission properties of capped CNT55 systems with or without alkali metal atom adsorption were systematically investigated by density functional theory calculation.The results indicate that the adsorption of alkali metal on the center site of a CNT tip is energetically favorable.In addition,the adsorption energies increase with the introduction of the electric field.The excessive negative charges on CNT tips make electron emittance much easier and result in a decrease in work function.Furthermore,the inducing effect by positively charged alkali metal atoms can be reasonably considered as the dominant reason for the improvement in field emission properties.展开更多
A semi-empirical atomic structure model method is developed in the framework of a relativistic case. This method starts from Dirac–Fock calculations using B-spline basis set. The core-valence electron correction is t...A semi-empirical atomic structure model method is developed in the framework of a relativistic case. This method starts from Dirac–Fock calculations using B-spline basis set. The core-valence electron correction is then treated in a semiempirical core polarization potential. As an application, the polarization properties of alkali metal atoms, including the static polarizabilities and long-range two-body dispersion coefficients, have been calculated. Our results are in good agreement with the results obtained from ab initio relativistic many-body perturbation method and the available experimental measurements.展开更多
基金financial support from European Union(Interreg FWVL V project PSYCHE)from the French National Research Agency(Multiprobe project,ANR-20-CE42-0007)。
文摘CO_(2)hydrogenation is an attractive way to store and utilize carbon dioxide generated by industrial processes,as well as to produce valuable chemicals from renewable and abundant resources.Iron catalysts are commonly used for the hydrogenation of carbon oxides to hydrocarbons.Iron-molybdenum catalysts have found numerous applications in catalysis,but have been never evaluated in the CO_(2)hydrogenation.In this work,the structural properties of iron-molybdenum catalysts without and with a promoting alkali metal(Li,Na,K,Rb,or Cs)were characterized using X-ray diffraction,hydrogen temperatureprogrammed reduction,CO_(2)temperature-programmed desorption,in-situ^(57)Fe Mossbauer spectroscopy and operando X-ray adsorption spectroscopy.Their catalytic performance was evaluated in the CO_(2)hydrogenation.During the reaction conditions,the catalysts undergo the formation of an iron(Ⅱ)molybdate structure,accompanied by a partial reduction of molybdenum and carbidization of iron.The rate of CO_(2)conversion and product selectivity strongly depend on the promoting alkali metals,and electronegativity was identified as an important factor affecting the catalytic performance.Higher CO_(2)conversion rates were observed with the promoters having higher electronegativity,while low electronegativity of alkali metals favors higher light olefin selectivity.
基金financial support from Natural Science Foundation of Inner Mongolia(No.2019MS05068)Inner Mongolia scientific and technological achievements transformation project(CGZH2018132)+3 种基金Inner Mongolia major science and technology project(2020ZD0024)the research project of Inner Mongolia Electric Power(Group)Co.,Ltd for post-doctoral studies,the Hong Kong Polytechnic University start-up funding,National Nature Science Foundation of China(No.51872157)Shenzhen Key Laboratory on Power Battery Safety Research(No.ZDSYS201707271615073)financial support from the Australian Research Council(DE190100445).
文摘The ever-growing pursuit of high energy density batteries has triggered extensive efforts toward developing alkali metal(Li,Na,and K)battery(AMB)technologies owing to high theoretical capacities and low redox potentials of metallic anodes.Typically,for new battery systems,the electrolyte design is critical for realizing the battery electrochemistry of AMBs.Conventional electrolytes in alkali ion batteries are generally unsuitable for sustaining the stability owing to the hyper-reactivity and dendritic growth of alkali metals.In this review,we begin with the fundamentals of AMB electrolytes.Recent advancements in concentrated and fluorinated electrolytes,as well as functional electrolyte additives for boosting the stability of Li metal batteries,are summarized and discussed with a special focus on structure-composition-performance relationships.We then delve into the electrolyte formulations for Na-and K metal batteries,including those in which Na/K do not adhere to the Li-inherited paradigms.Finally,the challenges and the future research needs in advanced electrolytes for AMB are highlighted.This comprehensive review sheds light on the principles for the rational design of promising electrolytes and offers new inspirations for developing stable AMBs with high performance.
基金support from the National Natural Science Foundation of China (52072257)the National Key Research and Development Program of China (2019YFE0118800).
文摘Alkali metal-carbon dioxide(Li/Na/K-CO_(2))batteries are emerging electrochemical energy storage technologies in the context of the energy crisis and the urgent demand for carbon neutrality.Alkali metal-CO_(2) batteries offer a new strategy for CO_(2) fixation and utilization,and thus has been receiving considerable attention in recent years.Considerable progress has been achieved since alkali metal-CO_(2) batteries were invented,especially in terms of development of new electrode materials,and yet,research is lacking on the underlying mechanisms of the systems.This is the first typical review focusing on the electrochemical mechanisms of metal-CO_(2) batteries that summarizes the current understanding of and provides insights into the thermodynamic reaction pathways,the kinetic characteristics,and the crucial factors determining the reaction mechanisms in alkali metal-CO_(2) batteries.The review starts with the fundamental concepts of alkali metal-CO_(2) batteries,followed by a comprehensive discussion of the working mechanisms on cathodes and anodes.Moreover,the operation mechanisms of state-of-the-art electrolytes,including liquid and(quasi-)solid-state electrolytes,are also described.Finally,we identify the unsolved problems in current alkali metal-CO_(2) batteries and propose potential topics for future research.
基金financially supported by the National Natural Science Foundation of China(22279112,52022088,51971245,51772262,21406191,U20A20336,21935009)the Natural Science Foundation of Hebei Province,China(B2022203018,F2021203097,B2020203037,B2018203297)+2 种基金the Hunan Innovation Team,China(2018RS3091)the Beijing Natural Science Foundation,China(2202046)the Fok Ying-Tong Education Foundation of China(171064)。
文摘Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transport kinetics of Li^(+)/Na^(+)/K^(+)in the 2×2 channels of a-MnO_(2)with a growth direction of[001]is revealed.We show that ion radius plays a decisive role in determining the ion transport and electrochemistry.Regardless of the ion radii,Li^(+)/Na^(+)/K^(+)can all go through the 2×2 channels of a-MnO_(2),generating large stress and causing channel merging or opening.However,smaller ions such as Li^(+)and Na^(+)cannot only transport along the[001]direction but also migrate along the<110>direction to the nanowire surface;for large ion such as K^(+),diffusion along the<110>direction is prohibited.The different ion transport behavior has grand consequences in the electrochemistry of metal oxygen batteries(MOBs).For Li-O_(2)battery,Li^(+)transports uniformly to the nanowire surface,forming a uniform layer of oxide;Na^(+)also transports to the nanowire surface but may be clogged locally due to its larger radius,therefore sporadic pearl-like oxides form on the nanowire surface;K^(+)cannot transport to the nanowire surface due to its large radius,instead,it breaks the nanowire locally,causing local deposition of potassium oxides.The study provides atomic scale understanding of the alkali metal ion transport mechanism which may be harnessed to improve the performance of MOBs.
基金financial support from the National Natural Science Foundation of China (Nos.21972157,21972160,and 22202224)the CAS Project for Young Scientists in Basic Research (No.YSBR-005)+2 种基金the Key Research Program of Frontier Sciences CAS (No.ZDBS-LY-7007)the CAS Project for Internet Security and Information Technology (No.CAS-WX2021SF0110)the funding support from Beijing Advanced Innovation Center for Materials Genome Engineering,Synfuels China,Co.Ltd.and Inner Mongolia University of Technology。
文摘Cobalt nanoparticles(NPs)catalysts are extensively used in heterogeneous catalytic reactions,and the addition of alkali metal promoters is a common method to modulate the catalytic performance because the catalyst's surface structures and morphologies are sensitive to the addition of promoters.However,the underlying modulation trend remains unclear.Herein,the adsorption of alkali metal promoters(Na and K)on the surfaces of face-centered-cubic(FCC)and hexagonal-closest packed(HCP)polymorphous cobalt was systematically investigated using density functional theory.Furthermore,the effect of alkali promoters on surface energies and nanoparticle morphologies was revealed on the basis of Wulff theory.For FCC-Co,the exposed area of the(111)facet in the nanoparticle increases with the adsorption coverage of alkali metal oxide.Meanwhile,the(311),(110),and(100)facets would disappear under the higher adsorption coverage of alkali metals.For HCPCo,the Wulff morphology is dominated by the(0001)and(1011)facets and is independent of the alkali metal adsorption coverage.This work provides insights into morphology modulation by alkali metal promoters for the rational design and synthesis of cobalt-based nanomaterials with desired facets and morphologies.
基金surported by the Jilin Province Science and Technology Development Project(No.20220203017SF)Industrialization Project of the 13th Five-Year"Education Department of Jilin Province(No.JJKH20200334KJ)the National Natural Sci-ence Foundation of China(No.11704143).
文摘Bis(15-crown-5)-stilbenes containing crown ether parts have been widely used in a variety of chemical applications,such as cation detectors,because of their ability to selectively bind to alkali metal cations,Bis(15-crown-5)-stilbenes and its derivatives with complexation of one-or two-alkali metal cation(Li^(+),Na^(+)and K^(+))have been theoretically investigat-ed by quantum chemistry methods.The coordination of alkali cations results in partial shrinkage of crown ethers,which directly affected natural distribution analysis charges and molecular orbital energy levels.The number of alkali metal ions has significant effects on absorption spectra and mean second hyperpolarizability.When one alkali metal ion was added to the anticonformer of bis(15-crown-5)-stilbene,the absorption spectra were obvious-ly redshifted and the mean second hyperpolarizability values were slightly increased;while two alkali metal ions were added to bis(15-crown-5)-stilbene,the absorption spectra were ob-viously blue shifted and the mean second hyperpolarizability values decreased.On the other hand,as the radius of the alkali ions increased,the mean second hyperpolarizability values of the compounds increased gradually.It is indicated that the mean second hyperpolarizability value is sensitive to the number and radius of the alkali metal cations,thus the third order nonlinear optical response can be used as a signal to detect the number and type of alkali met-al ions.
基金supported by NSFC(21473094 and21421001)MOE Innovation Team(IRT13022) in China
文摘Rechargeable alkali metal-air batteries are considered as the most promising candidate for the power source of electric vehicles(EVs) due to their high energy density. However, the practical application of metal-air batteries is still challenging. In the past decade, many strategies have been purposed and explored, which promoted the development of metal-air batteries. The reaction mechanisms have been gradually clarified and catalysts have been rationally designed for air cathodes. In this review, we summarize the recent development of alkali metal-air batteries from four parts: metal anodes, electrolytes, air cathodes and reactant gases, wherein we highlight the important achievement in this filed. Finally problems and prospective are discussed towards the future development of alkali metal-air batteries.
文摘EAB zeolite was successfully prepared and applied to selective adsorption of Li^(+),Na^(+)and K^(+)ions.The physical and chemical properties of the adsorbent were characterized by X-ray diffraction(XRD),X-ray fluorescence(XRF),scanning electron microscope(SEM)and thermogravimetry(TG)methods.The ion exchange behaviours for Li^(+),Na^(+)and K^(+)ions in monomcomponent and multicomponent solutions were studied.In independent ion exchange,the ion exchange capacities ratiosα(/Na/Li)andα(K/Li)were 3.8 and 6.2,respectively.In competitive ion exchange,the selectivitiesβ(Na/Li)andβ(K/Li)increased with the initial concentrations and reached 409 and 992 when the initial concentrations was 100 mmol/L.The thermodynamic study results showed that Gibbs free energy change(ΔGΘ)of ion exchange reaction between Li-EAB and K^(+)was-34.96 kJ/mol,indicating that ion exchange of K^(+)ions was more energetically favourable than Li^(+)ions.The calculation results showed that the energy barriers of ion exchange increased in the order K^(+)Na^(+)<Li^(+).The study shows that EAB zeolite is potential to be used in the separation of alkali ions.
基金the National Key R&D Research Program of China(Grant No.2018YFB0905400)the National Natural Science Foundation of China(Grant Nos.51872277,21606003,51902062,51972067,51802044,51925207 and U1910210)+2 种基金the Fundamental Research Funds for the Central Universities(WK2060140026)the DNL cooperation Fund,CAS(DNL180310)the Guangdong Natural Science Funds for Distinguished Young Scholar(Grant No.2019B151502039)。
文摘Alkali metal ion batteries(AMIBs)are playing an irreplaceable part in the energy revolution,due to their intrinsic advantages of large capacity/power density and abundance of alkali metal ions in the earth’s crust.Despite their great promise,the inborn deficiencies of commercial graphite and other anodes being researched so far call for the quest of better alternatives that exhibit all-round performance with the balance of energy/power density and cycling stability.Gallium-based materials,with impressive capacity utilization and self-healing ability,provide an anticipated solution to this conundrum.In this review,an overview on the recent progress of gallium-based anodes and their storage mechanism is presented.The current strategies used as engineering solutions to meet the scientific challenges ahead are discussed,in addition to the insightful outlook for possible future study.
文摘In this paper, the interaction parameters in the subregular solution model, λ1 and λ2, are regarded as a linear function of temperature, T. Therefore, the molar excess Gibbs energy of A-B binary system may be reexpressed as follows: GmE= xAxB[(λ11 +λ 12T) + (λ21 + λ22T)xB] The calculation of the model parameters. λ11 ,λ12, λ21 and λ22, was carried out numerically from the phase diagrams for 11 alkali metal-alkali halide or alkali earth metal-halide systems. In addition, artificial neural network trained by known data has been used to predict the values of these model parameters. The predicted results are in good agreement with the calculated ones. The applicability of the subregular solution model to the alkali metal-alkali halide or alkali earth metal-halide systems were tested by comparing the available experimental composition along the boundary of miscibility gap with the calculated ones which were obtained by using genetic algorithm. The good agreement between the calculated and experimental results across the entire liquidus is valid evidence in support of the model.
基金This work was supported by the National Key Research Development Program of China(2017YFB0601900)National Nature Science Foundation of China(51806220,51922040),China Postdoctoral Science Foundation(2019TQ0091)+1 种基金Grants from Fok Ying Tung Education Foundation(161051)Fundamental Research Funds for the Central Universities(2020MS020,2020DF01).
文摘The catalytic effects of alkali metal ions(Na^(+)and K^(+))on NO_(x)precursor formation during coal pyrolysis were investigated using the N-containing compound pyridine as a model compound.Density functional theory calculations at the B3LYP/6-31G(d,p)level of theory were conducted to elucidate the mechanism of pyridine pyrolysis and the pathways for HCN formation.The calculation results indicate that Na^(+)and K^(+)have distinct influences on different pyrolysis reactions;these alkali metal ions facilitate the initial hydrogen transfer from C_(1)to N and C_(2),whereas they hinder the other hydrogen migration reactions.Both Na^(+)and K^(+)significantly reduce the activation energies for C–C bond breakage and triple-bond formation,whereas they increase the activation energies for the isomerization reactions.The different effects essentially result from the distinct charge distributions induced by the two ions.Due to the distinct influences on the different reactions,the rate-determining steps are modulated,affecting the competitiveness of the different possible pathways of HCN formation.The formation of HCN from pyridine is promoted in the presence of Na^(+)and K^(+)because all the overall activation energies are decreased for different pathways.The calculation results agree well with previous experimental studies.Thus,the findings offer a new and promising approach to reveal the formation mechanism of NO_(x)and facilitate the control of NO_(x)for coal utilization.
基金Project supported by the the National Natural Science Foundation of China(Grant Nos.52062035 and 51861023)the Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province,China(Grant No.20213BCJ22056).
文摘Based on the density functional theory calculations,we have investigated the feasibility of two-dimensionalβ-GeS monolayer as high-performance anodes for alkali metal ion batteries.The results show that the electrical conductivity of β-GeS monolayer can be enhanced after adsorbing the alkali metal atoms owing to the semiconductor-to-metal transition.The low diffusion barriers of alkali metal atoms on the β-GeS surface indicate a rapid charge/discharge rate without metal clustering.Moreover,the low average open-circuit voltage(0.211 V)and a high theoretical capacity(1024 mAh·g^(-1))for Na suggest that theβ-GeS monolayer is a promising anode material for Na-ion batteries with high performance.
基金supported by the National Natural Science Foundation of China(No.51621001)the National Key Research and Development Program of China(No.2016YFA0202604)Key Laboratory of Resource Chemistry,Ministry of Education Joint International Research Laboratory of Resource Chemistry and the open fund from Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion(No.2018TP1037-202005)。
文摘Alloyed based anode materials with high theoretical specific capacity and low reaction potential are considered to be highly potential high-energy density anode materials for alkali metal ion batteries(AMIBs).Thus,the design of alloyed based materials with high electrochemical performance has attracted great attention.Among the numerous characterization methods for guiding electrode materials design,in situ transmission electron microscopy(TEM)gradually plays an irreplaceable role due to its high temporal and spatial resolution in directly observing the change of morphology,crystal structure and element evolutions.Herein,we reviewed the two current research hotspots and mainly focused on the structure design of alloyed based electrode material under the guidance of in situ TEM.Specifically,various nanostructure designs of alloyed based electrode materials with guidance of in situ TEM were employed to solve the key scientific issues of the violent volume change during alloying/dealloying processes for enhanced electrochemical performances.Mainly through introducing buffer space in the electrode material to reduce volume change to improve structural stability,including porous structure(0 D),nanotube structure(1 D),simple hollow structure,yolk-shell structure and some hybrid hollow structures(3 D).Furthermore,the direct guidance of in situ TEM is expected for creating new opportunities to nextgeneration electrode material design for AMIBs.
基金This work was financially supported by the Key Program of Frontier Science of Chinese Academy of Sciences(QYZDY-SSW-JSC038)the Natural Science Foundation of Guangdong Province(2017A030310185)the Science and Technology Planning Project of Guangzhou,China(201704030040).
文摘Sulfur dioxide(SO_(2))emissions from diesel exhaust pose a serious threat to the environment and human health.Thus,desulfurization technology and the performance of desulfurization materials must be improved.In this study,MnO_(2) was modified with various alkali metal ions using the impregnation method to enhance its SO_(2) capture performance.The composites were characterized intensively by scanning electron microscopy,energydispersive X-ray spectroscopy,X-ray diffraction spectroscopy,and Brunauer-Emmett-Teller theory.The SO_(2) capture performance of these composites were measured via thermogravimetry,and the effect of doping with alkali metal ions on the SO_(2) capture performance of MnO_(2) was investigated.Results showed that the SO_(2) capture performance of MnO_(2) could be enhanced by doping with alkali metal ions,and the MnO_(2) composite doped with LiOH(2.0 mol/L)had the best SO_(2) capture capacity(124 mgSO_(2)/gMaterial),which was 18%higher than that of pure MnO_(2).Moreover,the type and concentration of alkali metal ions had varying effects on the SO_(2) capture performance of MnO_(2).In our experiment,the SO_(2) capture performance of the MnO_(2) doped with NaOH,LiCl,Na2CO3,K2CO3,and Li2CO3 composites were worse than that of pure MnO_(2).Therefore,the influences of the type and concentration of alkali metal ions to be doped into desulfurization materials must be considered comprehensively.
文摘In order to employ the waste heat effectively,a novel three-stage integrated system based upon a solid oxide fuel cell(SOFC),an alkali metal thermoelectric converter(AMTEC)and thermally regenerative electrochemical cycles(TRECs)is put forward.Considering the main electrochemically and thermodynamically irreversible losses,the power output and the efficiency of the subsystems and the integrated system are compared,and optimally operating regions for the current density,the power output,and the efficiency of the integrated system are explored.Calculations demonstrate that the maximum power density of the considered system is up to 7466 W/m2,which allows 18%and 74%higher than that of the conventional SOFC-AMTEC device and the stand-alone fuel cell model,respectively.It is proved that the considered system is an efficient approach to boost energy efficiency.Moreover,the influence of several significant parameters on the comprehensive performance of the integrated system is expounded in detail,including the electrolyte thickness of the SOFC,the leakage resistance of the SOFC,and the area ratio between the SOFC electrode and the AMTEC subsystem.
文摘Metal-organic frameworks(MOFs) have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here,a typical metal-organic framework HKUST-1(also named Cu-BTC or MOF-199) was chemically reduced by doping it with alkali metals(Li, Na and K) and they were further used to investigate their CO2 adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction(XRD), thermo-gravimetric analysis(TGA)and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO2 storage capacity of HKUST-1 doped with moderate quantities of Li+, Na+and K+, individually, was greater than that of unmodified HKUST-1. The highest CO2 adsorption uptake of 8.64mmol/g was obtained with 1K-HKUST-1, and it was ca. 11% increase in adsorption capacity at 298 K and 18 bar as compared with HKUST-1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO2 than those of N2. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO2 after 10 cycles.
基金Project supported by the Key Program of the National Natural Science Foundation of China(Grant Nos.21031001 and U1034003)the National Natural Science Foundation of China(Grant Nos.20971040 and 21173072)the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China(Grant No.708029)
文摘The electronic structures and field emission properties of capped CNT55 systems with or without alkali metal atom adsorption were systematically investigated by density functional theory calculation.The results indicate that the adsorption of alkali metal on the center site of a CNT tip is energetically favorable.In addition,the adsorption energies increase with the introduction of the electric field.The excessive negative charges on CNT tips make electron emittance much easier and result in a decrease in work function.Furthermore,the inducing effect by positively charged alkali metal atoms can be reasonably considered as the dominant reason for the improvement in field emission properties.
基金supported by the National Basic Research Program of China(Grant No.2012CB821305)the National Natural Science Foundation of China(Grant Nos.11034009 and 11274246)
文摘A semi-empirical atomic structure model method is developed in the framework of a relativistic case. This method starts from Dirac–Fock calculations using B-spline basis set. The core-valence electron correction is then treated in a semiempirical core polarization potential. As an application, the polarization properties of alkali metal atoms, including the static polarizabilities and long-range two-body dispersion coefficients, have been calculated. Our results are in good agreement with the results obtained from ab initio relativistic many-body perturbation method and the available experimental measurements.
