An electrolyte model for the solid oxide fuel cell (SOFC) with proton conducting perovskite electrolyte is developed in this study, in which four types of charge carriers including proton, oxygen vacancy (oxide ion), ...An electrolyte model for the solid oxide fuel cell (SOFC) with proton conducting perovskite electrolyte is developed in this study, in which four types of charge carriers including proton, oxygen vacancy (oxide ion), free electron and electron hole are taken into consideration. The electrochemical process within the SOFC with hydrogen as the fuel is theoretically analyzed. With the present model, the effects of some parameters, such as the thickness of electrolyte, operating temperature and gas composition, on the ionic transport (or gas permeation) through the electrolyte and the electrical performance, i.e., the electromotive force (EMF) and internal resistance of the cell, are investigated in detail. The theoretical results are tested partly by comparing with the experimental data obtained from SrCe0.95M0.05O3-α, (M=Yb, Y) cells.展开更多
In this paper, the effect of hydrogen reduction of silver ions on the performance and structure of new solid polymer electrolyte polyetherimide (PEI)/Pebax2533 (Polynylonl2/tetramethylene oxide block copolymer, PA1...In this paper, the effect of hydrogen reduction of silver ions on the performance and structure of new solid polymer electrolyte polyetherimide (PEI)/Pebax2533 (Polynylonl2/tetramethylene oxide block copolymer, PA12-PTMO)/AgBF4 composite membranes is investigated. For PEI/Pebax2533/AgBF4 composite membranesprepared with dillerent AgBF4 concentration, the permeances of propylene and ethylene increase with the increase of AgBF4 concentration due to the carrier-facilitated transport, resulting in a high selectivity. But for propyl- ene/propane mixture, the mixed-gas selectivity is lower than its ideal selectivity. The hydrogen reduction strongly influences the membrane performance, which causes the decrease of propylene permeance and the increase of pro-pane permeance. With the increase of hydrogen reduction time, the membranes show a clearly color change from white to brown, yielding a great selectivity loss. The data of X-ray diffraction and FT-IR prove that silver ions are reduced to Ago after hydrogen reduction, and aggregated on the surface of PEI/Pebax2533/AgBF4 composite mem- branes.展开更多
The electromotive force (e.m.f.) of solid oxide fuel cells using biomass produced gas (BPG) as the fuels is calculated at 700-1,200 K using an in-house computer program, based on thermodynamic equilibrium analysis...The electromotive force (e.m.f.) of solid oxide fuel cells using biomass produced gas (BPG) as the fuels is calculated at 700-1,200 K using an in-house computer program, based on thermodynamic equilibrium analysis. Tour program also predicts the concentration of oxygen in the fuel chamber as well as the concentration of equilibrium species such as H2, CO, CO2 and CH4. Compared with using hydrogen as a fuel, the e.m.f. for cells using BPG as the fuels is relative low and strongly influenced by carbon deposition. To remove carbon deposition, the optimum amount of H2O to add is determined at various operating temperatures. Further the e.m.f, for cells based on yttria stabilized zirconia and doped ceria as electrolytes are compared. The study reveals that when using BPG as fuel, the depression of e.m.f, for a SOFC using doped ceria as electrolyte is relatively small when compared with that using Yttria stabilized zirconia.展开更多
The (1-x)BaZr0.9Y0.1O3-δ(BZY)-xCe0.8Sm0.2O2-δ(SDC, x =0.1,0.3,0.5 and 0.7) composite electrolytes were prepared by combining a gel polymerization method with a ball milling. X-ray diffraction (XRD) patterns show the...The (1-x)BaZr0.9Y0.1O3-δ(BZY)-xCe0.8Sm0.2O2-δ(SDC, x =0.1,0.3,0.5 and 0.7) composite electrolytes were prepared by combining a gel polymerization method with a ball milling. X-ray diffraction (XRD) patterns show the mixture of BZY and SDC is only crystalline phase as the composite electrolyte. The relative density,grain size and total conductivity of composite electrolytes increase significantly with the increase of SDC content. The maximum conductivity of 0.1 BZY-0.9 SDC reaches 2×10^2 S·cm^-1 at 600 ℃ in wet air,which is close to the conductivity of SDC.展开更多
Lithium-ion conductor Liz.3Alo.3Ti1.7(P04)3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol (1,2-PG)-assisted sol-gel method and characterized by differential thermal analysis-therm...Lithium-ion conductor Liz.3Alo.3Ti1.7(P04)3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol (1,2-PG)-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning elec- tron microscopy, electrochemical impedance spectroscopy, and chronoamperornetry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solu- tion is obtained without the precipitation of Ti4+ and A13+ with PO43- Well crystallized Lil.3Alo.3Til.7(PO4)3 can be prepared at much lower temperatures from 850 ~C to 950 ~C within a shorter synthesis time compared with that prepared at a temperature above 1000 ~C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 ℃ with an activation energy as low as 36.6 k J/tool for the specimen pre-sintered at 700 ℃ and sintered at 850 ℃. The high conductivity, good chemi- cal stability and easy fabrication of the Li1.3Al0.3Ti1.7(PO4)a provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.展开更多
K2FeO4 powders were synthesized by the ex-situ and in-situ electrochemical methods, respectively, and characterized by infrared spectrum (IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) a...K2FeO4 powders were synthesized by the ex-situ and in-situ electrochemical methods, respectively, and characterized by infrared spectrum (IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and BET. Their electrochemical performances were investigated by means of galvanostatic discharge and electrochemi-cal impedance spectroscopy (EIS). The results of physical characterization showed that the two samples have simi-lar structural features, but their surface morphologies and oriented growth of the crystals are different, which results in smaller specific surface area and lower solubility of the ex-situ electrosynthesized K2FeO4 sample. The results of discharge experiments indicated that the ex-situ electrosythesized K2FeO4 electrode has much larger discharge ca-pacity and lower electrode polarization than the in-situ electrosynthesized K2FeO4 electrode. It was found from the results of EIS that lower electrochemical polarization might be responsible for the improvement on the discharge performance of the ex-situ electrosynthesized K2FeO4 electrode.展开更多
Principally the basis of ISE is selecting of a support solid matrix and a nonsoluble compound or complexes of insighted cation, mixed with this solid. For preparing the ISE membranes there are some materials such PVC,...Principally the basis of ISE is selecting of a support solid matrix and a nonsoluble compound or complexes of insighted cation, mixed with this solid. For preparing the ISE membranes there are some materials such PVC, PE, organic polyelectrolytes, conducting polymers and inorganic compounds. The black white microscope photos are included, too. Detailed schemes and pictures of the electrodes and correlations were shown in the following article. Results are seen compatible for construction of the versatile ISE electrodes.展开更多
X-ray emission from metal cathodes in glow discharge (current is up to 300 mA, voltage is 1,500-4,300 V) experiments in the spectral range from 700 eV to 6 keV has been observed. The effect has been seen with a vari...X-ray emission from metal cathodes in glow discharge (current is up to 300 mA, voltage is 1,500-4,300 V) experiments in the spectral range from 700 eV to 6 keV has been observed. The effect has been seen with a variety of different metal cathodes (including AI, Sc, Ti, V, Ni, Nb, Zr, Mo, Pd, Ta, W, and Pt), as well as with different gasses (including D2, H2, Kr, Ar, and Xe) at low pressure (3-10 Torr). We present results from a variety of diagnostics, including: pinhole camera imaging; thermo luminescent detector measurements; time-resolved scintillator measurements; and a curved mica spectrometer to register X-ray spectra. Both diffuse and collimated X-ray emission have been observed.. Diffuse emission occurs in bursts of X-rays; with up to 10^5 bursts per second, with up to 10^6 photons per burst during the discharge. Collimated X-ray emission appears in the form of beamlets directed normal to the cathodes surface with a very small angular divergence; with up to 104 bursts per second, and up to 1013 photons overall up to 20 h after discharge switch off. Based on these experimental results we propose a phenomenological model of processes.展开更多
For All-Solid-State battery applications, Mg2+-ion conducting polymer electrolytes and Mg-metal electrode are currently considered as alternate choices in place of Li+-ion conducting polymer electrolytes/Li-metal el...For All-Solid-State battery applications, Mg2+-ion conducting polymer electrolytes and Mg-metal electrode are currently considered as alternate choices in place of Li+-ion conducting polymer electrolytes/Li-metal electrode. Present paper reports fabrication of All-Solid-State battery based on the following Mg2+-ion conducting nano composite polymer electrolyte (NCPE) films: [85PEO: 15Mg(C104)2] + 5% TiO2 (〈 100 nm), [85PEO: 15Mg(CIO4)2] + 3% SiO2(-8 nm). [85PEO: 15Mg(CIO4)2] + 3% MgO (〈 100 nm), [85PEO:15Mg(C1O4)2] + 3% MgO (-44 μm). NCPE films were prepared by hot-press technique. Solid Polymer Electrolyte (SPE) composition: [85PEO: 15Mg(CIO4)2], identified as high conducting film at room temperature, has been used as ISt--phase host and nano/micro particles of active (MgO)/passive (SiO2, TiO2) fillers as IInd-phase dispersoid. Filler particle dependent conductivity studies identified above mentioned NCPE films as optimum conducting composition (OCC) at room temperature. Ion transport behavior of SPE/NCPE film materials was investigated previously. Present paper reports materials characterization and cell performance studies on All-Solid-State batteries: Mg (Anode) Ⅱ SPE or NCPE films tt C+MnO2+Electrolyte (Cathode). Open circuit voltage (OCV) obtained was in the range: 1.79-1.92 V. The batteries were discharged at room temperature under different load conditions and some important battery parameters have been evaluated from plateau region of cell-potential discharge profiles. All the batteries performed quite satisfactorily specially under low current drain states.展开更多
Solid oxide fuel cell–proton exchange membrane(SOFC–PEM) hybrid system is being foreseen as a valuable alternative for power generation. As this hybrid system is a conceptual design, many uncertainties involving inp...Solid oxide fuel cell–proton exchange membrane(SOFC–PEM) hybrid system is being foreseen as a valuable alternative for power generation. As this hybrid system is a conceptual design, many uncertainties involving input values should be considered at the early stage of process optimization. We present in this paper a generalized framework of multi-objective optimization under uncertainty for the synthesis/design optimization of the SOFC–PEM hybrid system. The framework is based on geometric, economic and electrochemical models and focuses on evaluating the effect of uncertainty in operating parameters on three conflicting objectives: electricity efficiency, SOFC current density and capital cost of system. The multi-objective optimization provides solutions in the form of a Pareto surface, with a range of possible synthesis/design solutions and a logical procedure for searching the global optimum solution for decision maker. Comparing the stochastic and deterministic Pareto surfaces of different objectives, we conclude that the objectives are considerably influenced by uncertainties because the two trade-off surfaces are different.展开更多
Solid electrolyte based-resistive memories have been considered to be a potential candidate for future information technology with applications in non-volatile memory, logic circuits and neuromorphic computing. A cond...Solid electrolyte based-resistive memories have been considered to be a potential candidate for future information technology with applications in non-volatile memory, logic circuits and neuromorphic computing. A conductive filament model has been generally accepted to be the underlying mechanism for the resistive switching. However, the growth dynamics of such conductive filaments is still not fully understood. Here, we explore the controllability of filament growth by correlating observations of the filament growth with the electric field distribution and several other factors. The filament growth behavior has been recorded using in situ transmission electron microscopy. By studying the real- time recorded filament growth behavior and morphologies, we have been able to simulate the electric field distribution in accordance with our observations. Other factors have also been shown to affect the filament growth, such as Joule heating and electrolyte infrastructure. This work provides insight into the controllable growth of conductive filaments and will help guide research into further functionalities of nanoionic resistive memories.展开更多
Solid-state lithium-metal-batteries(SSLMBs)using garnet Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)as the solid electrolyte are expected to conquer the safety concerns of high energy Li batteries with organic liquid e...Solid-state lithium-metal-batteries(SSLMBs)using garnet Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)as the solid electrolyte are expected to conquer the safety concerns of high energy Li batteries with organic liquid electrolytes owing to its nonflammable nature and good mechanical strength.However,the poor interfacial contact between the Li anode and LLZTO greatly restrains the practical applications of the electrolyte,because large polarization,dendritic Li formation and penetration can occur at the interfaces.Here,an effective method is proposed to improve the wettability of the LLZTO toward lithium and reduce the interfacial resistance by engineering universal lithiophilic interfacial layers.Thanks to the in-situ formed lithiophilic and ionic conductive Co/Li_(2)O interlayers,the symmetric Li/CoO-LLZTO/Li batteries present much smaller overpotential,ultra-low areal specific resistance(ASR,12.3 X cm^(2)),high critical current density(CCD,1.1 mA cm^(-2)),and outstanding cycling performance(1696 h at a current density of 0.3 mA cm^(-2))at 25℃.Besides,the solid-state Li/CoO-LLZTO/LFP cells deliver an excellent electrochemical performance with a high coulombic efficiency of~100%and a long cycling time over 185 times.Surprisingly,the high-voltage(4.6 V)solid state Li/CoO-LLZTO/Li_(1.4)Mn_(0.6)Ni_(0.2)Co_(0.2)O_(2.4)(LMNC622)batteries can also realize an ultra-high specific capacity(232.5 mAh g-1)under 0.1 C at 25℃.This work paves an effective way for practical applications of the dendrite-free SSLMBs.展开更多
Inorganic solid electrolytes have distinguished advantages in terms of safety and stability, and are promising to substitute for conventional organic liquid electrolytes. However, low ionic conductivity of typical can...Inorganic solid electrolytes have distinguished advantages in terms of safety and stability, and are promising to substitute for conventional organic liquid electrolytes. However, low ionic conductivity of typical candidates is the key problem. As connective diffusion path is the prerequisite for high performance, we screen for possible solid electrolytes from the 2004 International Centre for Diffraction Data (ICDD) database by calculating conduction pathways using Bond Valence (BV) method. There are 109846 inorganic crystals in the 2004 ICDD database, and 5295 of them contain lithium. Except for those with toxic, radioactive, rare, or variable valence elements, 1380 materials are candidates for solid electrolytes. The rationality of the BV method is approved by comparing the existing solid electrolytes' conduction pathways we had calculated with those from ex- periments or first principle calculations. The implication for doping and substitution, two important ways to improve the conductivity, is also discussed. Among them LizCO3 is selected for a detailed comparison, and the pathway is reproduced well with that based on the density functional studies. To reveal the correlation between connectivity of pathways and conductivity, a/γ-LiAlO2 and Li2CO3 are investigated by the impedance spectrum as an example, and many experimental and theoretical studies are in process to indicate the relationship between property and structure. The BV method can calculate one material within a few minutes, providing an efficient way to lock onto targets from abundant data, and to investigate the struc- ture-property relationship systematically.展开更多
The growth of lithium(Li)whiskers is detrimental to Li batteries.However,it remains a challenge to directly track Li whisker growth.Here we report in situ observations of electrochemically induced Li deposition under ...The growth of lithium(Li)whiskers is detrimental to Li batteries.However,it remains a challenge to directly track Li whisker growth.Here we report in situ observations of electrochemically induced Li deposition under a CO_(2) atmosphere inside an environmental transmission electron microscope.We find that the morphology of individual Li deposits is strongly influenced by the competing processes of cracking and self-healing of the solid electrolyte interphase(SEI).When cracking overwhelms self-healing,the directional growth of Li whiskers predominates.In contrast,when self-healing dominates over cracking,the isotropic growth of round Li particles prevails.The Li deposition rate and SEI constituent can be tuned to control the Li morphologies.We reveal a new“weak-spot”mode of Li dendrite growth,which is attributed to the operation of the Bardeen-Herring growth mechanism in the whisker’s cross section.This work has implications for the control of Li dendrite growth in Li batteries.展开更多
Although graphite anodes operated with representative de/intercalation patterns at low potentials are considered highly desirable for K-ion batteries,the severe capacity fading caused by consecutive reduction reaction...Although graphite anodes operated with representative de/intercalation patterns at low potentials are considered highly desirable for K-ion batteries,the severe capacity fading caused by consecutive reduction reactions on the aggressively reactive surface is inevitable given the scarcity of effective protecting layers.Herein,by introducing a flame-retardant localized high-concentration electrolyte with retentive solvation configuration and relatively weakened anion-coordination and non-solvating fluorinated ether,the rational solid electrolyte interphase characterized by well-balanced inorganic/organic components is tailored in situ.This effectively prevented solvents from excessively decomposing and simultaneously improved the resistance against K-ion transport.Consequently,the graphite anode retained a prolonged cycling capability of up to 1400 cycles(245 mA h g,remaining above 12 mon)with an excellent capacity retention of as high as 92.4%.This is superior to those of conventional and high-concentration electrolytes.Thus,the optimized electrolyte with moderate salt concentration is perfectly compatible with graphite,providing a potential application prospect for K-storage evolution.展开更多
Graphite thin film anodes with a high IR reflectivity have been prepared by a spin coating method. Both ex situ and in situ mi- croscope FTIR spectroscopy (MFFIRS) in a reflection configuration were employed to inve...Graphite thin film anodes with a high IR reflectivity have been prepared by a spin coating method. Both ex situ and in situ mi- croscope FTIR spectroscopy (MFFIRS) in a reflection configuration were employed to investigate interfacial processes of the graphite thin film anodes in lithium-ion batteries. A solid electrolyte interphase layer (SEI layer) was formed on the cycled graphite thin film anode. Ex situ MFTIRS revealed that the main components of the SEI layer on cycled graphite film anodes in 1 tool L 1 LiPF6/ethylene carbonate + dimethyl carbonate (1:1) are alkyl lithium carbonates (ROCOzLi). The desolvation process on graphite anodes during the initial intercalation of lithium ion with graphite was also observed and analyzed by in situ MFTIRS.展开更多
Iron difluoride(FeF_(2))is considered a highcapacity cathode material for lithium-ion batteries.However,its specific capacity and stability are limited by the poor electrochemical kinetics of conversion reactions.Here...Iron difluoride(FeF_(2))is considered a highcapacity cathode material for lithium-ion batteries.However,its specific capacity and stability are limited by the poor electrochemical kinetics of conversion reactions.Herein,the conversion reaction is confined in a localized nanosized space by encapsulating FeF_(2) nanoparticles in polymer gelatin.The FeF_(2) nanocrystal-coated polyvinylidene fluoride-based layer(defined as Fe F_(2) @100%G-40%P)was synthesized by glucoseassisted in-situ gelatinization to construct an artificial cathode solid electrolyte interphase via a solvothermal process.Thanks to the improved kinetics of the localized conversion reaction,the obtained FeF_(2) @100%G-40%P electrodes show good cyclic stability(313mAhg^(-1) after 150 cycles at 100 mAg^(-1) ,corresponding to a retention of 80%)and a high rate performance(186.6 mAhg^(-1) at 500 mAg^(-1)).展开更多
electrolyte. The properties of lithium-ion (Li-ion) battery, such as cycle life, irreversible capacity loss, self-discharge rate, electrode corrosion and safety are usually ascribed to the quality of the SEI, which ar...electrolyte. The properties of lithium-ion (Li-ion) battery, such as cycle life, irreversible capacity loss, self-discharge rate, electrode corrosion and safety are usually ascribed to the quality of the SEI, which are highly dependent on the thickness. Thus, understanding the formation mechanism and the SEI thickness is of prime interest. First, we apply dimensional analysis to obtain an explicit relation between the thickness and the number density in this study. Then the SEI thickness in the initial charge-discharge cycle is analyzed and estimated for the first time using the Cahn-Hilliard phase-field model. In addition, the SEI thickness by molecular dynamics simulation validates the theoretical results. It has been shown that the established model and the simulation in this paper estimate the SEI thickness concisely within order-of-magnitude of nanometers. Our results may help in evaluating the performance of SEI and assist the future design of Li-ion battery.展开更多
With the proliferation of energy storage and power applications, electric vehicles particularly, solid-state batteries are considered as one of the most promising strategies to address the ever-increasing safety conce...With the proliferation of energy storage and power applications, electric vehicles particularly, solid-state batteries are considered as one of the most promising strategies to address the ever-increasing safety concern and high energy demand of power devices. Here, we demonstrate the Al4B2O9 nanorods-modified poly(ethylene oxide) (PEO)-based solid polymer electrolyte (ASPE) with high ionic conductivity, wide electrochemical window, decent mechanical property and nonflammable performance. Specifically, because of the longer-range ordered Li+ transfer channels conducted by the interaction between Al4B2O9 nanorods and PEO, the optimal ASPE (ASPE-1) shows excellent ionic conductivity of 4.35×10^−1 and 3.1×10^−1 S cm^−1 at 30 and 60℃, respectively. It also has good electrochemical stability at 60℃ with a decomposition voltage of 5.1 V. Besides, the assembled LiFePO4//Li cells show good cycling performance, delivering 155 mA h g−1 after 300 cycles at 1 C under 60℃, and present excellent low temperature adaptability, retaining over 125 mA h g^−1 after 90 cycles at 0.2 C under 30℃. These results verify that the addition of Al4B2O9 nanorods can effectively promote the integrated performance of solid polymer electrolyte.展开更多
文摘An electrolyte model for the solid oxide fuel cell (SOFC) with proton conducting perovskite electrolyte is developed in this study, in which four types of charge carriers including proton, oxygen vacancy (oxide ion), free electron and electron hole are taken into consideration. The electrochemical process within the SOFC with hydrogen as the fuel is theoretically analyzed. With the present model, the effects of some parameters, such as the thickness of electrolyte, operating temperature and gas composition, on the ionic transport (or gas permeation) through the electrolyte and the electrical performance, i.e., the electromotive force (EMF) and internal resistance of the cell, are investigated in detail. The theoretical results are tested partly by comparing with the experimental data obtained from SrCe0.95M0.05O3-α, (M=Yb, Y) cells.
基金Supported by the National Natural Science Foundation of China (20776137) and the National High Technology Research and Develooment Prozram of China (2008AA06Z325).
文摘In this paper, the effect of hydrogen reduction of silver ions on the performance and structure of new solid polymer electrolyte polyetherimide (PEI)/Pebax2533 (Polynylonl2/tetramethylene oxide block copolymer, PA12-PTMO)/AgBF4 composite membranes is investigated. For PEI/Pebax2533/AgBF4 composite membranesprepared with dillerent AgBF4 concentration, the permeances of propylene and ethylene increase with the increase of AgBF4 concentration due to the carrier-facilitated transport, resulting in a high selectivity. But for propyl- ene/propane mixture, the mixed-gas selectivity is lower than its ideal selectivity. The hydrogen reduction strongly influences the membrane performance, which causes the decrease of propylene permeance and the increase of pro-pane permeance. With the increase of hydrogen reduction time, the membranes show a clearly color change from white to brown, yielding a great selectivity loss. The data of X-ray diffraction and FT-IR prove that silver ions are reduced to Ago after hydrogen reduction, and aggregated on the surface of PEI/Pebax2533/AgBF4 composite mem- branes.
基金V. ACKN0WLEDGMENT This work was supported by the National Natural Science Foundation of China (No.50372066 and No.50332040).
文摘The electromotive force (e.m.f.) of solid oxide fuel cells using biomass produced gas (BPG) as the fuels is calculated at 700-1,200 K using an in-house computer program, based on thermodynamic equilibrium analysis. Tour program also predicts the concentration of oxygen in the fuel chamber as well as the concentration of equilibrium species such as H2, CO, CO2 and CH4. Compared with using hydrogen as a fuel, the e.m.f. for cells using BPG as the fuels is relative low and strongly influenced by carbon deposition. To remove carbon deposition, the optimum amount of H2O to add is determined at various operating temperatures. Further the e.m.f, for cells based on yttria stabilized zirconia and doped ceria as electrolytes are compared. The study reveals that when using BPG as fuel, the depression of e.m.f, for a SOFC using doped ceria as electrolyte is relatively small when compared with that using Yttria stabilized zirconia.
基金National Natural Science Foundation of China(No.51102216)Program for the Innovative Talents of Higher Learning Institutions of Shanxi Province+1 种基金Natural Science Foundation for Young Scientists of Shanxi Province(No.2012021021-1)Shanxi Scholarship Council of China(No.2012-071)
文摘The (1-x)BaZr0.9Y0.1O3-δ(BZY)-xCe0.8Sm0.2O2-δ(SDC, x =0.1,0.3,0.5 and 0.7) composite electrolytes were prepared by combining a gel polymerization method with a ball milling. X-ray diffraction (XRD) patterns show the mixture of BZY and SDC is only crystalline phase as the composite electrolyte. The relative density,grain size and total conductivity of composite electrolytes increase significantly with the increase of SDC content. The maximum conductivity of 0.1 BZY-0.9 SDC reaches 2×10^2 S·cm^-1 at 600 ℃ in wet air,which is close to the conductivity of SDC.
文摘Lithium-ion conductor Liz.3Alo.3Ti1.7(P04)3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol (1,2-PG)-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning elec- tron microscopy, electrochemical impedance spectroscopy, and chronoamperornetry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solu- tion is obtained without the precipitation of Ti4+ and A13+ with PO43- Well crystallized Lil.3Alo.3Til.7(PO4)3 can be prepared at much lower temperatures from 850 ~C to 950 ~C within a shorter synthesis time compared with that prepared at a temperature above 1000 ~C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 ℃ with an activation energy as low as 36.6 k J/tool for the specimen pre-sintered at 700 ℃ and sintered at 850 ℃. The high conductivity, good chemi- cal stability and easy fabrication of the Li1.3Al0.3Ti1.7(PO4)a provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.
基金Supported by the National Natural Science Foundation of China (No.50172041)partly by the Chinese State Key Labora-tory for Corrosion and Protection.
文摘K2FeO4 powders were synthesized by the ex-situ and in-situ electrochemical methods, respectively, and characterized by infrared spectrum (IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and BET. Their electrochemical performances were investigated by means of galvanostatic discharge and electrochemi-cal impedance spectroscopy (EIS). The results of physical characterization showed that the two samples have simi-lar structural features, but their surface morphologies and oriented growth of the crystals are different, which results in smaller specific surface area and lower solubility of the ex-situ electrosynthesized K2FeO4 sample. The results of discharge experiments indicated that the ex-situ electrosythesized K2FeO4 electrode has much larger discharge ca-pacity and lower electrode polarization than the in-situ electrosynthesized K2FeO4 electrode. It was found from the results of EIS that lower electrochemical polarization might be responsible for the improvement on the discharge performance of the ex-situ electrosynthesized K2FeO4 electrode.
文摘Principally the basis of ISE is selecting of a support solid matrix and a nonsoluble compound or complexes of insighted cation, mixed with this solid. For preparing the ISE membranes there are some materials such PVC, PE, organic polyelectrolytes, conducting polymers and inorganic compounds. The black white microscope photos are included, too. Detailed schemes and pictures of the electrodes and correlations were shown in the following article. Results are seen compatible for construction of the versatile ISE electrodes.
文摘X-ray emission from metal cathodes in glow discharge (current is up to 300 mA, voltage is 1,500-4,300 V) experiments in the spectral range from 700 eV to 6 keV has been observed. The effect has been seen with a variety of different metal cathodes (including AI, Sc, Ti, V, Ni, Nb, Zr, Mo, Pd, Ta, W, and Pt), as well as with different gasses (including D2, H2, Kr, Ar, and Xe) at low pressure (3-10 Torr). We present results from a variety of diagnostics, including: pinhole camera imaging; thermo luminescent detector measurements; time-resolved scintillator measurements; and a curved mica spectrometer to register X-ray spectra. Both diffuse and collimated X-ray emission have been observed.. Diffuse emission occurs in bursts of X-rays; with up to 10^5 bursts per second, with up to 10^6 photons per burst during the discharge. Collimated X-ray emission appears in the form of beamlets directed normal to the cathodes surface with a very small angular divergence; with up to 104 bursts per second, and up to 1013 photons overall up to 20 h after discharge switch off. Based on these experimental results we propose a phenomenological model of processes.
文摘For All-Solid-State battery applications, Mg2+-ion conducting polymer electrolytes and Mg-metal electrode are currently considered as alternate choices in place of Li+-ion conducting polymer electrolytes/Li-metal electrode. Present paper reports fabrication of All-Solid-State battery based on the following Mg2+-ion conducting nano composite polymer electrolyte (NCPE) films: [85PEO: 15Mg(C104)2] + 5% TiO2 (〈 100 nm), [85PEO: 15Mg(CIO4)2] + 3% SiO2(-8 nm). [85PEO: 15Mg(CIO4)2] + 3% MgO (〈 100 nm), [85PEO:15Mg(C1O4)2] + 3% MgO (-44 μm). NCPE films were prepared by hot-press technique. Solid Polymer Electrolyte (SPE) composition: [85PEO: 15Mg(CIO4)2], identified as high conducting film at room temperature, has been used as ISt--phase host and nano/micro particles of active (MgO)/passive (SiO2, TiO2) fillers as IInd-phase dispersoid. Filler particle dependent conductivity studies identified above mentioned NCPE films as optimum conducting composition (OCC) at room temperature. Ion transport behavior of SPE/NCPE film materials was investigated previously. Present paper reports materials characterization and cell performance studies on All-Solid-State batteries: Mg (Anode) Ⅱ SPE or NCPE films tt C+MnO2+Electrolyte (Cathode). Open circuit voltage (OCV) obtained was in the range: 1.79-1.92 V. The batteries were discharged at room temperature under different load conditions and some important battery parameters have been evaluated from plateau region of cell-potential discharge profiles. All the batteries performed quite satisfactorily specially under low current drain states.
基金Supported by the National Natural Science Foundation of China(50876117)the Fundamental Research Funds for the Central Universities(CDJXS11141149)
文摘Solid oxide fuel cell–proton exchange membrane(SOFC–PEM) hybrid system is being foreseen as a valuable alternative for power generation. As this hybrid system is a conceptual design, many uncertainties involving input values should be considered at the early stage of process optimization. We present in this paper a generalized framework of multi-objective optimization under uncertainty for the synthesis/design optimization of the SOFC–PEM hybrid system. The framework is based on geometric, economic and electrochemical models and focuses on evaluating the effect of uncertainty in operating parameters on three conflicting objectives: electricity efficiency, SOFC current density and capital cost of system. The multi-objective optimization provides solutions in the form of a Pareto surface, with a range of possible synthesis/design solutions and a logical procedure for searching the global optimum solution for decision maker. Comparing the stochastic and deterministic Pareto surfaces of different objectives, we conclude that the objectives are considerably influenced by uncertainties because the two trade-off surfaces are different.
文摘Solid electrolyte based-resistive memories have been considered to be a potential candidate for future information technology with applications in non-volatile memory, logic circuits and neuromorphic computing. A conductive filament model has been generally accepted to be the underlying mechanism for the resistive switching. However, the growth dynamics of such conductive filaments is still not fully understood. Here, we explore the controllability of filament growth by correlating observations of the filament growth with the electric field distribution and several other factors. The filament growth behavior has been recorded using in situ transmission electron microscopy. By studying the real- time recorded filament growth behavior and morphologies, we have been able to simulate the electric field distribution in accordance with our observations. Other factors have also been shown to affect the filament growth, such as Joule heating and electrolyte infrastructure. This work provides insight into the controllable growth of conductive filaments and will help guide research into further functionalities of nanoionic resistive memories.
基金supported by the National Natural Science Foundation of China (21603019 and 201503025)Program for the Hundred Talents Program of Chongqing University。
文摘Solid-state lithium-metal-batteries(SSLMBs)using garnet Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)as the solid electrolyte are expected to conquer the safety concerns of high energy Li batteries with organic liquid electrolytes owing to its nonflammable nature and good mechanical strength.However,the poor interfacial contact between the Li anode and LLZTO greatly restrains the practical applications of the electrolyte,because large polarization,dendritic Li formation and penetration can occur at the interfaces.Here,an effective method is proposed to improve the wettability of the LLZTO toward lithium and reduce the interfacial resistance by engineering universal lithiophilic interfacial layers.Thanks to the in-situ formed lithiophilic and ionic conductive Co/Li_(2)O interlayers,the symmetric Li/CoO-LLZTO/Li batteries present much smaller overpotential,ultra-low areal specific resistance(ASR,12.3 X cm^(2)),high critical current density(CCD,1.1 mA cm^(-2)),and outstanding cycling performance(1696 h at a current density of 0.3 mA cm^(-2))at 25℃.Besides,the solid-state Li/CoO-LLZTO/LFP cells deliver an excellent electrochemical performance with a high coulombic efficiency of~100%and a long cycling time over 185 times.Surprisingly,the high-voltage(4.6 V)solid state Li/CoO-LLZTO/Li_(1.4)Mn_(0.6)Ni_(0.2)Co_(0.2)O_(2.4)(LMNC622)batteries can also realize an ultra-high specific capacity(232.5 mAh g-1)under 0.1 C at 25℃.This work paves an effective way for practical applications of the dendrite-free SSLMBs.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11234013 and 51172274)the "Strategic Priority Research Program" of the Chinese Academy of Sciences (Grant No. XDA01010202)+1 种基金the National Basic Research Program of China (Grant No. 2012CB932900)the Project of Beijing Municipal Science & Technology Commission
文摘Inorganic solid electrolytes have distinguished advantages in terms of safety and stability, and are promising to substitute for conventional organic liquid electrolytes. However, low ionic conductivity of typical candidates is the key problem. As connective diffusion path is the prerequisite for high performance, we screen for possible solid electrolytes from the 2004 International Centre for Diffraction Data (ICDD) database by calculating conduction pathways using Bond Valence (BV) method. There are 109846 inorganic crystals in the 2004 ICDD database, and 5295 of them contain lithium. Except for those with toxic, radioactive, rare, or variable valence elements, 1380 materials are candidates for solid electrolytes. The rationality of the BV method is approved by comparing the existing solid electrolytes' conduction pathways we had calculated with those from ex- periments or first principle calculations. The implication for doping and substitution, two important ways to improve the conductivity, is also discussed. Among them LizCO3 is selected for a detailed comparison, and the pathway is reproduced well with that based on the density functional studies. To reveal the correlation between connectivity of pathways and conductivity, a/γ-LiAlO2 and Li2CO3 are investigated by the impedance spectrum as an example, and many experimental and theoretical studies are in process to indicate the relationship between property and structure. The BV method can calculate one material within a few minutes, providing an efficient way to lock onto targets from abundant data, and to investigate the struc- ture-property relationship systematically.
基金financial support by the National Key Research and Development Program of China (2018YFB0104300)National Natural Science Foundation of China (51772262, U20A20336, and 21935009)+6 种基金Natural Science Foundation of Hebei Province (B2020203037)Hunan Innovation Team (2018RS3091)financial support by Fok YingTong Education Foundation of China (171064)Natural Science Foundation of Hebei Province (B2018203297)financial support by the National Natural Science Foundation of China (52022088 and 51971245)Beijing Natural Science Foundation (2202046)financial support by the National Natural Science Foundation of China (51971195)。
文摘The growth of lithium(Li)whiskers is detrimental to Li batteries.However,it remains a challenge to directly track Li whisker growth.Here we report in situ observations of electrochemically induced Li deposition under a CO_(2) atmosphere inside an environmental transmission electron microscope.We find that the morphology of individual Li deposits is strongly influenced by the competing processes of cracking and self-healing of the solid electrolyte interphase(SEI).When cracking overwhelms self-healing,the directional growth of Li whiskers predominates.In contrast,when self-healing dominates over cracking,the isotropic growth of round Li particles prevails.The Li deposition rate and SEI constituent can be tuned to control the Li morphologies.We reveal a new“weak-spot”mode of Li dendrite growth,which is attributed to the operation of the Bardeen-Herring growth mechanism in the whisker’s cross section.This work has implications for the control of Li dendrite growth in Li batteries.
基金supported by the National Natural Science Foundation of China(91963118 and 52173246)Science Technology Program of Jilin Province(20200201066JC)the 111 Project(B13013)。
文摘Although graphite anodes operated with representative de/intercalation patterns at low potentials are considered highly desirable for K-ion batteries,the severe capacity fading caused by consecutive reduction reactions on the aggressively reactive surface is inevitable given the scarcity of effective protecting layers.Herein,by introducing a flame-retardant localized high-concentration electrolyte with retentive solvation configuration and relatively weakened anion-coordination and non-solvating fluorinated ether,the rational solid electrolyte interphase characterized by well-balanced inorganic/organic components is tailored in situ.This effectively prevented solvents from excessively decomposing and simultaneously improved the resistance against K-ion transport.Consequently,the graphite anode retained a prolonged cycling capability of up to 1400 cycles(245 mA h g,remaining above 12 mon)with an excellent capacity retention of as high as 92.4%.This is superior to those of conventional and high-concentration electrolytes.Thus,the optimized electrolyte with moderate salt concentration is perfectly compatible with graphite,providing a potential application prospect for K-storage evolution.
基金supported by the National Natural Science Foundation of China (21003102, 21021002)the Fundamental Research Funds for the Central Universities (2012121035)the National Basic Research Program of China (2009CB220102)
文摘Graphite thin film anodes with a high IR reflectivity have been prepared by a spin coating method. Both ex situ and in situ mi- croscope FTIR spectroscopy (MFFIRS) in a reflection configuration were employed to investigate interfacial processes of the graphite thin film anodes in lithium-ion batteries. A solid electrolyte interphase layer (SEI layer) was formed on the cycled graphite thin film anode. Ex situ MFTIRS revealed that the main components of the SEI layer on cycled graphite film anodes in 1 tool L 1 LiPF6/ethylene carbonate + dimethyl carbonate (1:1) are alkyl lithium carbonates (ROCOzLi). The desolvation process on graphite anodes during the initial intercalation of lithium ion with graphite was also observed and analyzed by in situ MFTIRS.
基金supported by the Science and Technology Commission of Shanghai Municipality(20520710400,19JC1412600 and 18230743400)the National Natural Science Foundation of China(21771124 and 21901156)+1 种基金the Oceanic Interdisciplinary Program(SL2020MS020)the SJTU-Warwick Joint Seed Fund(2019/20)of Shanghai Jiao Tong University。
文摘Iron difluoride(FeF_(2))is considered a highcapacity cathode material for lithium-ion batteries.However,its specific capacity and stability are limited by the poor electrochemical kinetics of conversion reactions.Herein,the conversion reaction is confined in a localized nanosized space by encapsulating FeF_(2) nanoparticles in polymer gelatin.The FeF_(2) nanocrystal-coated polyvinylidene fluoride-based layer(defined as Fe F_(2) @100%G-40%P)was synthesized by glucoseassisted in-situ gelatinization to construct an artificial cathode solid electrolyte interphase via a solvothermal process.Thanks to the improved kinetics of the localized conversion reaction,the obtained FeF_(2) @100%G-40%P electrodes show good cyclic stability(313mAhg^(-1) after 150 cycles at 100 mAg^(-1) ,corresponding to a retention of 80%)and a high rate performance(186.6 mAhg^(-1) at 500 mAg^(-1)).
基金supported by the National Natural Science Foundation of China (Grant Nos. 11372313, U1562105, and 11611130019)the Chinese Academy of Sciences (CAS) through CAS Interdisciplinary Innovation Team Project, the CAS Key Research Program of Frontier Sciences (Grant No. QYZDJ-SSW-JSC019)the CAS Strategic Priority Research Program (Grant No. XDB22040401)
文摘electrolyte. The properties of lithium-ion (Li-ion) battery, such as cycle life, irreversible capacity loss, self-discharge rate, electrode corrosion and safety are usually ascribed to the quality of the SEI, which are highly dependent on the thickness. Thus, understanding the formation mechanism and the SEI thickness is of prime interest. First, we apply dimensional analysis to obtain an explicit relation between the thickness and the number density in this study. Then the SEI thickness in the initial charge-discharge cycle is analyzed and estimated for the first time using the Cahn-Hilliard phase-field model. In addition, the SEI thickness by molecular dynamics simulation validates the theoretical results. It has been shown that the established model and the simulation in this paper estimate the SEI thickness concisely within order-of-magnitude of nanometers. Our results may help in evaluating the performance of SEI and assist the future design of Li-ion battery.
基金financially supported by the National Natural Science Foundation of China (51804344)the Huxiang Youth Talent Support Program (2019RS2002)+2 种基金the Innovation and Entrepreneurship Project of Hunan Province,China (2018GK5026)the Innovation-Driven Project of Central South University (2020CX027)Guangdong Yang Fan Plan for Postdoctor Program
文摘With the proliferation of energy storage and power applications, electric vehicles particularly, solid-state batteries are considered as one of the most promising strategies to address the ever-increasing safety concern and high energy demand of power devices. Here, we demonstrate the Al4B2O9 nanorods-modified poly(ethylene oxide) (PEO)-based solid polymer electrolyte (ASPE) with high ionic conductivity, wide electrochemical window, decent mechanical property and nonflammable performance. Specifically, because of the longer-range ordered Li+ transfer channels conducted by the interaction between Al4B2O9 nanorods and PEO, the optimal ASPE (ASPE-1) shows excellent ionic conductivity of 4.35×10^−1 and 3.1×10^−1 S cm^−1 at 30 and 60℃, respectively. It also has good electrochemical stability at 60℃ with a decomposition voltage of 5.1 V. Besides, the assembled LiFePO4//Li cells show good cycling performance, delivering 155 mA h g−1 after 300 cycles at 1 C under 60℃, and present excellent low temperature adaptability, retaining over 125 mA h g^−1 after 90 cycles at 0.2 C under 30℃. These results verify that the addition of Al4B2O9 nanorods can effectively promote the integrated performance of solid polymer electrolyte.