Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stab...Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.展开更多
Four-dimensional(4D)printing technology is a revolutionary development that produces structures that can adapt in response to external stimuli.However,the responsiveness and printability of smart materials with shape ...Four-dimensional(4D)printing technology is a revolutionary development that produces structures that can adapt in response to external stimuli.However,the responsiveness and printability of smart materials with shape memory properties,which are necessary for 4D printing,remain limited.Biomass materials derived from nature have offered an effective solution due to their various excellent and unique properties.Biomass materials have been abundant in resources and low in carbon content,contributing to the then-current global green energy-saving goals,including carbon peaking and carbon neutrality.This review focused on different sources of biomass materials used in 4D printing,including plant-based,animal-based,and microbial-based biomass materials.It systematically outlined the responsive deformation mechanisms of printed objects that contained biomass materials and delved into the roles and unique advantages of biomass materials in those printed objects.Leveraging these advantages,the review discussed the potential applications of biomass materials in biomedicine,food printing,and other fields to support ongoing development and application efforts.Additionally,it emphasized the crucial role played by bio-fabrication technologies utilizing biomass materials in the integration of biomass materials with 4D printing.Finally,this paper discussed the then-current challenges and potential future directions of biomass materials in 4D printing,aiming to promote the effective development of biomass materials in 4D printing applications.展开更多
CrTaO_(4)has been found to play a pivotal role in the protection of refractory high-entropy alloys(RHEAs)from high-temperature oxidation and thermal attack due to its high melting point,low thermal conductivity,close ...CrTaO_(4)has been found to play a pivotal role in the protection of refractory high-entropy alloys(RHEAs)from high-temperature oxidation and thermal attack due to its high melting point,low thermal conductivity,close thermal expansion coefficient(TEC)to RHEAs.These appealing properties enable CrTaO_(4)as a new type of protective scale material for high-temperature applications such as in air breathing jet engines.For such engine applications,CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS)corrosion is a critical issue.However,the corrosion behavior of CrTaO_(4)under CMAS attack remains unknown so far.Here,the corrosion resistance of CrTaO_(4)to molten CMAS is comprehensively studied.It is demonstrated that the CMAS corrosion resistance is significantly superior over commercial yttria-stabilized zirconia and the commonly investigated thermal barrier coating materials.Element and phase compositional analyses indicate dense and CMAS corrosion-resistant layers are established between CMAS and the CrTaO_(4)substrate.The interface reaction between the CrTaO_(4)substrate and CMAS at 1250 and 1300℃gives rise to a dense layer composed of CaTa_(2)O_(6) and Mg(Cr,Al)_(2)O_(4)spinel just beneath the molten CMAS.At 1350℃,a phase composition gradient layer,composed of crystalline phases CaTa_(2)O_(6)/CaTa_(2)O_(6)+Mg(Cr,Al)_(2)O_(4)/CaTa_(2)O_(6)+Cr2O_(3),is formed.With increased calcium consumption due to more Ca-containing crystalline phase formation upon elevating temperature,the Ca/Si ratio in CMAS melt declines,thereby increasing the viscosity of the melt and mitigating the penetration of CMAS into the CrTaO_(4)substrate.展开更多
To explore high value-added utilization pathways of fly ash,the mesoporous structure of silicon dioxide extracted from fly ash(FA-SiO_(2))was utilized to restrict the dicyandiamide(DCDA)thermal degradation process.Thi...To explore high value-added utilization pathways of fly ash,the mesoporous structure of silicon dioxide extracted from fly ash(FA-SiO_(2))was utilized to restrict the dicyandiamide(DCDA)thermal degradation process.This produced chemically bonded interacting composite photocatalysts of FA-SiO,and graphitic-phase carbon nitride(g-C_(3)N_(4)).Compared with the spherical silicon dioxide prepared using tetraethyl orthosilicate(TEOS-SiO_(2)),the mesoporous structure of FA-SiO_(2),allowed DCDA to react in a smaller space,which facilitated the transformation of DCDA to melamine by the thermal degradation kinetics of FA-C_(3)N_(4)/DCDA.This ultimately boosted the formation of an N-atom-removed triazine ring structure and a multistage structure combining lumps and rods in the composite photocatalysts of g-C_(3)N_(4),and FA-SiO_(2),which led to a higher visible-light utilization efficiency,a suitable valence-band position,and the photocatalytic activity for methylene blue reaching 3.56 times that of g-C_(3)N_(4).The findings indicate that mesoporous FA-SiO,has the potential to improve the structural and photocatalytic properties of g-C_(3)N_(4),-based materials.展开更多
The LiMnPO4/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical performance tests were adopted to...The LiMnPO4/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical performance tests were adopted to characterize the properties of LiMnPO4/C. The XRD studies show that the pure olivine phase LiMnPO4 can be obtained at a low temperature of 500 °C. The SEM analyses illustrate that the citric acid used as the chelating reagent and carbon source can restrain the particle size of LiMnPO4/C well. The LiMnPO4/C sample synthesized at 500 °C for 10 h performs the highest initial discharge capacity of 122.6 mA-h/g, retaining 112.4 mA-h/g over 30 cycles at 0.05C rate. The citric acid based sol-gel method is favor to obtain the high electrochemical performance of LiMnPO4/C.展开更多
The Li3V2（PO4）3/C composite cathode material was synthesized via sol-gel method using three different chelating agents （citric acid, salicylic acid and polyacrylic acid） at pH value of 3 or 7. The crystal structur...The Li3V2（PO4）3/C composite cathode material was synthesized via sol-gel method using three different chelating agents （citric acid, salicylic acid and polyacrylic acid） at pH value of 3 or 7. The crystal structure, morphology, specific surface area and electrochemical performance of the prepared samples were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS） and galvanostatic charge/discharge test. The results show that the effects of pH value on the performance of the prepared materials are greatly related to the chelating agents. With salicylic acid or polyacrylic acid as the chelating reagent, the structure, morphology and electrochemical performance of the samples are greatly influenced by the pH values. However, the structure of the materials with citric acid as the chelating agent does not change as pH value changes, and the materials own uniform particle size distribution and good electrochemical performance. It delivers an initial discharge capacity of 113.58 mA·h/g at 10C, remaining as high as 108.48 mA·h/g after 900 cycles, with a capacity retention of 95.51%.展开更多
LiFePO4-Li3V2（PO4）3 composites were synthesized by solid-hydrothermal method and by ball milling,respectively.The electrochemical performance of the solid-hydrothermally obtained materials（C-LFVP） was significantl...LiFePO4-Li3V2（PO4）3 composites were synthesized by solid-hydrothermal method and by ball milling,respectively.The electrochemical performance of the solid-hydrothermally obtained materials（C-LFVP） was significantly improved compared with LiFePO4（LFP） and Li3V2（PO4）3（LVP）,and it was also much better than that of the ball-milled LiFePO4-Li3V2（PO4）3（P-LFVP）.C-LFVP and P-LFVP both had four REDOX peaks（voltage plateaus）,which coincided with that of LFP and LVP.Some new trace substances were found in C-LFVP which had more perfect morphology,this was responsible for the better electrochemical performance of C-LFVP than P-LFVP.展开更多
Li3V2（PO4）3 precursor was obtained with V2Os.nH2O , LiOH＇H2O, NH4H2PO4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li3Vz（PO4）3 cathode material was prepared by sint...Li3V2（PO4）3 precursor was obtained with V2Os.nH2O , LiOH＇H2O, NH4H2PO4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li3Vz（PO4）3 cathode material was prepared by sintering the amorphous Li3V2（PO4）3. The as-sintered samples were investigated by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, N2 adsorption-desorption and electrochemical measurement. It is found that Li3Vz（PO4）3 sintered at 700 ℃ possesses good wormhole-like mesoporous structure with the largest specific surface area of 188 cmZ/g, and the smallest pore size of 9.3 nm. Electrochemical test reveals that the initial discharge capacity of the 700 ℃ sintered sample is 155.9 mA.h/g at the rate of 0.2C, and the capacity retains 154 mA.h/g after 50 cycles, exhibiting a stable discharge capacity at room temperature.展开更多
Li3V2-2/3xMnx（PO4）3（0≤x≤0.12） powders were synthesized by sol-gel method. The effect of Mn2＋-doping on the structure and electrochemical performances of Li3V2（PO4）3/C was characterized by XRD, SEM, XPS, galva...Li3V2-2/3xMnx（PO4）3（0≤x≤0.12） powders were synthesized by sol-gel method. The effect of Mn2＋-doping on the structure and electrochemical performances of Li3V2（PO4）3/C was characterized by XRD, SEM, XPS, galvanostatic charge /discharge and electrochemical impedance spectroscopy（EIS）. The XRD study shows that a small amount of Mn2＋-doped does not alter the structure of Li3V2（PO4）3/C materials, and all Mn2＋-doped samples are of pure single phase with a monoclinic structure （space group P21/n）. The XPS analysis indicates that valences state of V and Mn are ＋3 and ＋2 in Li3V1.94Mn0.09（PO4）3/C, respectively, and the citric acid in raw materials was decomposed into carbon during calcination, and residual carbon exists in Li3V1.94Mn0.09（PO4）/C. The results of electrochemical measurements show that Mn2＋-doping can improve the cyclic stability and rate performance of these cathode materials. The Li3V1.94Mn0.09（PO4）3/C cathode material shows the best cyclic stability and rate performance. For example, at the discharge current density of 40 mA/g, after 100 cycles, the discharge capacity of Li3V1.94Mn0.09（PO4）3/C declines from initial 158.8 mA·h/g to 120.5 mA·h/g with a capacity retention of 75.9%; however, that of the Mn-undoed sample declines from 164.2 mA·h/g to 72.6 mA·h/g with a capacity retention of 44.2%. When the discharge current is increased up to 1C, the intial discharge capacity of Li3V1.94Mn0.09（PO4）3/C still reaches 146.4 mA·h/g, and the discharge capacity maintains at 107.5 mA·h/g after 100 cycles. The EIS measurement indicates that Mn2＋-doping with a appropriate amount of Mn2＋ decreases the charge transfer resistance, which is favorable for the insertion/extraction of Li＋.展开更多
In order to enhance electrochemical properties of LiFePO4 （LFP） cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The result...In order to enhance electrochemical properties of LiFePO4 （LFP） cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The results show that the spherical precursors with the sizes of 0.5-5 μm can be completely converted to LFP/C when the calcination temperature is higher than 500 ℃. The LFP/C microspheres obtained at calcination temperature of 700 ℃ are composed of numerous particles with sizes of -20 nm, and have well-developed interconnected pore structure and large specific surface area of 28.77 mE/g. The specific discharge capacities of the LFP/C obtained at 700 ℃ are 162.43, 154.35 and 144.03 mA.h/g at 0.5C, 1C and 2C, respectively. Meanwhile, the capacity retentions can reach up to 100% after 50 cycles. The improved electrochemical properties of the materials are ascribed to a small Li＋ diffusion resistance and special structure of LFP/C microspheres.展开更多
LiMnPO_4 /C composites were synthesized via solid-state reaction with different carbon sources: sucrose, citric acid and oxalic acid. The sam- ples were characterized by X-ray diffraction (XRD), scanning electron micr...LiMnPO_4 /C composites were synthesized via solid-state reaction with different carbon sources: sucrose, citric acid and oxalic acid. The sam- ples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical performance test. The results of XRD reveal that carbon coating has no effect on the phase of LiMnPO_4 . The LiMnPO_4 /C synthesized at 600 °C with citric acid as carbon source shows an initial discharge capacity of 117.8 mA·hg^-1 at 0.05 C rate. After 30 cycles, the capacity remains 98.2 mAh·g^-1 . The improved electrochemical properties of LiMnPO_4 /C is attributed to the decomposition of organic acid during the sintering process.展开更多
LiNiCoAlO（NCA） with Zr（OH）coating is demonstrated as high performance cathode material for lithium ion batteries（LIBs）. The coated materials are synthesized via a simple dry coating method of NCA with Zr（OH）po...LiNiCoAlO（NCA） with Zr（OH）coating is demonstrated as high performance cathode material for lithium ion batteries（LIBs）. The coated materials are synthesized via a simple dry coating method of NCA with Zr（OH）powders, and then characterized with scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and X-ray photoelectron spectroscopy（XPS）. Experimental results show that amorphous Zr（OH）powders have been successfully coated on the surface of spherical NCA particles, exhibiting improved electrochemical performance. 0.50 wt% Zr（OH）coated NCA delivers a capacity of 197.6 mAh/g at the first cycle and 154.3 mAh/g after 100 cycles with a capacity retention of 78.1% at 1 C rate. In comparison, the pure NCA shows a capacity of 194.6 mAh/g at the first cycle and 142.5 mAh/g after 100 cycles with a capacity retention of 73.2% at 1 C rate. Electrochemical impedance spectroscopy（EIS） results show that the coated material exhibits a lower resistance, indicating that the coating layer can efficiently suppress transition metals dissolution and decrease the side reactions at the surface between the electrode and electrolyte. Therefore, surface coating with amorphous Zr（OH）is a simple and useful method to enhance the electrochemical performance of NCA-based materials for the cathode of LIBs.展开更多
The rapid development of additive manufacturing and advances in shape memory materials have fueled the progress of four-dimensional （4D） printing. With the right external stimulus, the need for human interaction, se...The rapid development of additive manufacturing and advances in shape memory materials have fueled the progress of four-dimensional （4D） printing. With the right external stimulus, the need for human interaction, sensors, and batteries will be eliminated, and by using additive manufacturing, more complex devices and parts can be produced. With the current understanding of shape memory mechanisms and with improved design for additive manufacturing, reversibility in 4D printing has recently been proven to be feasible. Conventional one-way 4D printing requires human interaction in the programming （or shapesetting） phase, but reversible 4D printing, or two-way 4D printing, will fully eliminate the need for human interference, as the programming stage is replaced with another stimulus. This allows reversible 4D printed parts to be fully dependent on external stimuli; parts can also be potentially reused after every recovery, or even used in continuous cycles-an aspect that carries industrial appeal. This paper presents a review on the mechanisms of shape memory materials that have led to 4D printing, current findings regarding 4D printing in alloys and polymers, and their respective limitations. The reversibility of shape memory materials and their feasibility to be fabricated using three-dimensional （3D） printing are summarized and critically analyzed. For reversible 4D printing, the methods of 3D printing, mechanisms used for actuation, and strategies to achieve reversibility are also highlighted. Finally, prospective future research directions in reversible 4D printing are suggested.展开更多
A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-typ...A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-type Li2FeSiO4 sample with uniform and fine particle sizes is successfully and fast synthesized by microwave heating at 700 ℃ in 12 rain. And the obtained Li2FeSiO4 materials show better electrochemical performance and microstructure than those of Li2FeSiO4 sample by the conventional solidstate reaction. ？2009 Yan Bing Cao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
La-EDTA-Fe3O4 was prepared by a chemical co-precipitation method. The magnetic composite was characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD） and Fourier transform infrared spectros...La-EDTA-Fe3O4 was prepared by a chemical co-precipitation method. The magnetic composite was characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT-IR）. Furthermore, the adsorption properties of La-EDTA-Fe3O4 toward phosphate in water were investigated. The uptake rate of phosphate in water by La-EDTA-Fe3O4 was 3-1000 times than that of EDTA-Fe3O4, and reached 97.8% at 7 hr. The adsorption process agreed well with the Freundlich model and kinetics studies showed that the adsorption of phosphate proceeds according to pseudo second-order adsorption kinetics. The maximum removal rate was achieved at pH 6.0-7.0. The La-EDTA-Fe3O4 had good adsorption properties and could be separated well from aqueous solution by a permanent magnet. Therefore, this nanomaterial has potential application for the removal of phosphate from large water bodies.展开更多
Monocrystal LiMn_(0. 6)Fe_(0. 4)PO_4 cathode material was obtained via hydrothermal method at 180℃ for 10 h without any surfactant. The effects of hydrothermal time on the phase and morphology of the material were di...Monocrystal LiMn_(0. 6)Fe_(0. 4)PO_4 cathode material was obtained via hydrothermal method at 180℃ for 10 h without any surfactant. The effects of hydrothermal time on the phase and morphology of the material were discussed.By controlling the reaction solutions, the rodlike, flowerlike,and strawlike LiMn_(0.6)Fe_(0.4)PO_4 cathode materials were synthesized. Electrochemical performances show that the rodlike LiMn_(0. 6)Fe_(0. 4)PO_4 has the best electrochemical properties. The initial discharge capacity of the rodlike structure is 106.4 mAh·g^(-1), which is higher than those of flowerlike and strawlike materials.展开更多
Spherical LiFePO4 and LiFePO4/C composite powders for lithium ion batteries were synthesized by a novel processing route of co-precipitation and subsequent calcinations in a nitrogen and hydrogen atmosphere. The precu...Spherical LiFePO4 and LiFePO4/C composite powders for lithium ion batteries were synthesized by a novel processing route of co-precipitation and subsequent calcinations in a nitrogen and hydrogen atmosphere. The precursors of LiFePO4, LiFePO4/C composite and the resultant products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and the electrochemical performances were investigated by galvanostatic charge and discharge tests. The precursors composed of amorphous Fe3(PO4)2·xH2O and crystalline Li3PO4 obtained in the co-precipitation processing have a sphere-like morphology. The spherical LiFePO4 derived from the calcinations of the precursor at 700 ℃ for 10 h in a reduction atmosphere shows a discharge capacity of 119 mAh·g-1 at the C/10 rate, while the LiFePO4/C composite with 10wt.% carbon addition exhibits a discharge capacity of 140 mAh·g-1. The electrochemical performances indicate that the LiFePO4/C composite has a higher specific capacity and a more stable cycling performance than the bare olivine LiFePO4 due to the carbon addition enhancing the electronic conductivity.展开更多
Micro-sized（1030.3±178.4 nm） and nano-sized（50.4±8.0 nm） Fe3O4 particles have been fabricated through hydrogen thermal reduction of α-Fe2O3 particles synthesized by means of a hydrothermal process.The m...Micro-sized（1030.3±178.4 nm） and nano-sized（50.4±8.0 nm） Fe3O4 particles have been fabricated through hydrogen thermal reduction of α-Fe2O3 particles synthesized by means of a hydrothermal process.The morphology and microstructure of the micro-sized and the nano-sized Fe3O4 particles were characterized by X-ray diffraction,field-emission gun scanning electron microscopy,transmission electron microscopy and highresolution electron microscopy.The micro-sized Fe3O4 particles exhibit porous structure,while the nano-sized Fe3O4 particles are solid structure.Their electrochemical performance was also evaluated.The nano-sized solid Fe3O4 particles exhibit gradual capacity fading with initial discharge capacity of 1083.1 mAhg-1 and reversible capacity retention of 32.6% over 50 cycles.Interestingly,the micro-sized porous Fe3O4 particles display very stable capacity-cycling behavior,with initial discharge capacity of 887.5 mAhg-1 and charge capacity of 684.4 mAhg-1 at the 50th cycle.Therefore,77.1% of the reversible capacity can be maintained over 50 cycles.The micro-sized porous Fe3O4 particles with facile synthesis,good cycling performance and high capacity retention are promising candidate as anode materials for high energy-density lithium-ion batteries.展开更多
Four-dimensional printing allows for the transformation capabilities of 3D-printed architectures over time,altering their shape,properties,or function when exposed to external stimuli.This interdisciplinary technology...Four-dimensional printing allows for the transformation capabilities of 3D-printed architectures over time,altering their shape,properties,or function when exposed to external stimuli.This interdisciplinary technology endows the 3D architectures with unique functionalities,which has generated excitement in diverse research fields,such as soft robotics,biomimetics,biomedical devices,and sensors.Understanding the selection of the material,architectural designs,and employed stimuli is crucial to unlocking the potential of smart customization with 4D printing.This review summarizes recent significant developments in 4D printing and establishes links between smart materials,3D printing techniques,programmable structures,diversiform stimulus,and new functionalities for multidisciplinary applications.We start by introducing the advanced features of 4D printing and the key technological roadmap for its implementation.We then place considerable emphasis on printable smart materials and structural designs,as well as general approaches to designing programmable structures.We also review stimulus designs in smart materials and their associated stimulus-responsive mechanisms.Finally,we discuss new functionalities of 4D printing for potential applications and further development directions.展开更多
LiFePO4/Carbon composite cathode material was prepared using starch as carbon source by spray-pelleting and subsequent pyrolysis in N2. The samples were characterized by XRD, SEM, Raman, and their electrochemical perf...LiFePO4/Carbon composite cathode material was prepared using starch as carbon source by spray-pelleting and subsequent pyrolysis in N2. The samples were characterized by XRD, SEM, Raman, and their electrochemical performance was investigated in terms of cycling behavior. There has a special micro-morphology via the process, which is favorable to electrochemical properties. The discharge capacity of the LiFePO4.C composite was 170 mAh g-1, equal to the theoretical specific capacity at 0.1 C rate. At 4 C current density, the specific capacity was about 80 mAh g-1, which can satisfy for transportation applications if having a more flat discharge flat.展开更多
基金partly supported by the National Natural Science Foundation of China(Grant No.52272225).
文摘Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.
基金the support by National Natural Science Foundation of China(No.52375314,12472147,U23A20412)the National Key R&D Program of China(No.2024YFB4710205,2024YFD2200700)Heilongjiang Provincial Natural Science Foundation of China(No.2022ZX02C25).
文摘Four-dimensional(4D)printing technology is a revolutionary development that produces structures that can adapt in response to external stimuli.However,the responsiveness and printability of smart materials with shape memory properties,which are necessary for 4D printing,remain limited.Biomass materials derived from nature have offered an effective solution due to their various excellent and unique properties.Biomass materials have been abundant in resources and low in carbon content,contributing to the then-current global green energy-saving goals,including carbon peaking and carbon neutrality.This review focused on different sources of biomass materials used in 4D printing,including plant-based,animal-based,and microbial-based biomass materials.It systematically outlined the responsive deformation mechanisms of printed objects that contained biomass materials and delved into the roles and unique advantages of biomass materials in those printed objects.Leveraging these advantages,the review discussed the potential applications of biomass materials in biomedicine,food printing,and other fields to support ongoing development and application efforts.Additionally,it emphasized the crucial role played by bio-fabrication technologies utilizing biomass materials in the integration of biomass materials with 4D printing.Finally,this paper discussed the then-current challenges and potential future directions of biomass materials in 4D printing,aiming to promote the effective development of biomass materials in 4D printing applications.
基金supported by the National Natural Science Foundation of China(Nos.U23A20562 and 52302074).
文摘CrTaO_(4)has been found to play a pivotal role in the protection of refractory high-entropy alloys(RHEAs)from high-temperature oxidation and thermal attack due to its high melting point,low thermal conductivity,close thermal expansion coefficient(TEC)to RHEAs.These appealing properties enable CrTaO_(4)as a new type of protective scale material for high-temperature applications such as in air breathing jet engines.For such engine applications,CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS)corrosion is a critical issue.However,the corrosion behavior of CrTaO_(4)under CMAS attack remains unknown so far.Here,the corrosion resistance of CrTaO_(4)to molten CMAS is comprehensively studied.It is demonstrated that the CMAS corrosion resistance is significantly superior over commercial yttria-stabilized zirconia and the commonly investigated thermal barrier coating materials.Element and phase compositional analyses indicate dense and CMAS corrosion-resistant layers are established between CMAS and the CrTaO_(4)substrate.The interface reaction between the CrTaO_(4)substrate and CMAS at 1250 and 1300℃gives rise to a dense layer composed of CaTa_(2)O_(6) and Mg(Cr,Al)_(2)O_(4)spinel just beneath the molten CMAS.At 1350℃,a phase composition gradient layer,composed of crystalline phases CaTa_(2)O_(6)/CaTa_(2)O_(6)+Mg(Cr,Al)_(2)O_(4)/CaTa_(2)O_(6)+Cr2O_(3),is formed.With increased calcium consumption due to more Ca-containing crystalline phase formation upon elevating temperature,the Ca/Si ratio in CMAS melt declines,thereby increasing the viscosity of the melt and mitigating the penetration of CMAS into the CrTaO_(4)substrate.
基金supported by the Medical Special Cultivation Project of Anhui University of Science and Technology(Nos.YZ2023H2B013 and YZ2023H2B012),China.
文摘To explore high value-added utilization pathways of fly ash,the mesoporous structure of silicon dioxide extracted from fly ash(FA-SiO_(2))was utilized to restrict the dicyandiamide(DCDA)thermal degradation process.This produced chemically bonded interacting composite photocatalysts of FA-SiO,and graphitic-phase carbon nitride(g-C_(3)N_(4)).Compared with the spherical silicon dioxide prepared using tetraethyl orthosilicate(TEOS-SiO_(2)),the mesoporous structure of FA-SiO_(2),allowed DCDA to react in a smaller space,which facilitated the transformation of DCDA to melamine by the thermal degradation kinetics of FA-C_(3)N_(4)/DCDA.This ultimately boosted the formation of an N-atom-removed triazine ring structure and a multistage structure combining lumps and rods in the composite photocatalysts of g-C_(3)N_(4),and FA-SiO_(2),which led to a higher visible-light utilization efficiency,a suitable valence-band position,and the photocatalytic activity for methylene blue reaching 3.56 times that of g-C_(3)N_(4).The findings indicate that mesoporous FA-SiO,has the potential to improve the structural and photocatalytic properties of g-C_(3)N_(4),-based materials.
基金Project (0991025) supported by Natural Science Foundation of Guangxi, ChinaProject (51164007) supported by the National Natural Science Foundation of ChinaProject (201101ZD008) supported by Educational Commission of Guangxi, China
文摘The LiMnPO4/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical performance tests were adopted to characterize the properties of LiMnPO4/C. The XRD studies show that the pure olivine phase LiMnPO4 can be obtained at a low temperature of 500 °C. The SEM analyses illustrate that the citric acid used as the chelating reagent and carbon source can restrain the particle size of LiMnPO4/C well. The LiMnPO4/C sample synthesized at 500 °C for 10 h performs the highest initial discharge capacity of 122.6 mA-h/g, retaining 112.4 mA-h/g over 30 cycles at 0.05C rate. The citric acid based sol-gel method is favor to obtain the high electrochemical performance of LiMnPO4/C.
基金Project(2007BAQ01055)supported by the National Key Technology R&D Program of ChinaProject(2011SCU11081)supported by the Sichuan University Funds for Young Scientists,ChinaProject(20120181120103)supported by Ph.D.Programs Foundation of the Ministry of Education of China
文摘The Li3V2（PO4）3/C composite cathode material was synthesized via sol-gel method using three different chelating agents （citric acid, salicylic acid and polyacrylic acid） at pH value of 3 or 7. The crystal structure, morphology, specific surface area and electrochemical performance of the prepared samples were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS） and galvanostatic charge/discharge test. The results show that the effects of pH value on the performance of the prepared materials are greatly related to the chelating agents. With salicylic acid or polyacrylic acid as the chelating reagent, the structure, morphology and electrochemical performance of the samples are greatly influenced by the pH values. However, the structure of the materials with citric acid as the chelating agent does not change as pH value changes, and the materials own uniform particle size distribution and good electrochemical performance. It delivers an initial discharge capacity of 113.58 mA·h/g at 10C, remaining as high as 108.48 mA·h/g after 900 cycles, with a capacity retention of 95.51%.
基金Project (2007BAQ01055) supported by the National Key Technology R&D Programs of ChinaProject (50574063) supported by theNational Natural Science Foundation of China
文摘LiFePO4-Li3V2（PO4）3 composites were synthesized by solid-hydrothermal method and by ball milling,respectively.The electrochemical performance of the solid-hydrothermally obtained materials（C-LFVP） was significantly improved compared with LiFePO4（LFP） and Li3V2（PO4）3（LVP）,and it was also much better than that of the ball-milled LiFePO4-Li3V2（PO4）3（P-LFVP）.C-LFVP and P-LFVP both had four REDOX peaks（voltage plateaus）,which coincided with that of LFP and LVP.Some new trace substances were found in C-LFVP which had more perfect morphology,this was responsible for the better electrochemical performance of C-LFVP than P-LFVP.
基金Project (51162026) supported by the National Natural Science Foundation of ChinaProjects (20100480949, 201104509) supported by China Postdoctoral Science FoundationProject (133274341015501) supported by Postdoctoral Science Foundation of Central South University, China
文摘Li3V2（PO4）3 precursor was obtained with V2Os.nH2O , LiOH＇H2O, NH4H2PO4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li3Vz（PO4）3 cathode material was prepared by sintering the amorphous Li3V2（PO4）3. The as-sintered samples were investigated by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, N2 adsorption-desorption and electrochemical measurement. It is found that Li3Vz（PO4）3 sintered at 700 ℃ possesses good wormhole-like mesoporous structure with the largest specific surface area of 188 cmZ/g, and the smallest pore size of 9.3 nm. Electrochemical test reveals that the initial discharge capacity of the 700 ℃ sintered sample is 155.9 mA.h/g at the rate of 0.2C, and the capacity retains 154 mA.h/g after 50 cycles, exhibiting a stable discharge capacity at room temperature.
基金Project (20771100) supported by the National Natural Science Foundation of China
文摘Li3V2-2/3xMnx（PO4）3（0≤x≤0.12） powders were synthesized by sol-gel method. The effect of Mn2＋-doping on the structure and electrochemical performances of Li3V2（PO4）3/C was characterized by XRD, SEM, XPS, galvanostatic charge /discharge and electrochemical impedance spectroscopy（EIS）. The XRD study shows that a small amount of Mn2＋-doped does not alter the structure of Li3V2（PO4）3/C materials, and all Mn2＋-doped samples are of pure single phase with a monoclinic structure （space group P21/n）. The XPS analysis indicates that valences state of V and Mn are ＋3 and ＋2 in Li3V1.94Mn0.09（PO4）3/C, respectively, and the citric acid in raw materials was decomposed into carbon during calcination, and residual carbon exists in Li3V1.94Mn0.09（PO4）/C. The results of electrochemical measurements show that Mn2＋-doping can improve the cyclic stability and rate performance of these cathode materials. The Li3V1.94Mn0.09（PO4）3/C cathode material shows the best cyclic stability and rate performance. For example, at the discharge current density of 40 mA/g, after 100 cycles, the discharge capacity of Li3V1.94Mn0.09（PO4）3/C declines from initial 158.8 mA·h/g to 120.5 mA·h/g with a capacity retention of 75.9%; however, that of the Mn-undoed sample declines from 164.2 mA·h/g to 72.6 mA·h/g with a capacity retention of 44.2%. When the discharge current is increased up to 1C, the intial discharge capacity of Li3V1.94Mn0.09（PO4）3/C still reaches 146.4 mA·h/g, and the discharge capacity maintains at 107.5 mA·h/g after 100 cycles. The EIS measurement indicates that Mn2＋-doping with a appropriate amount of Mn2＋ decreases the charge transfer resistance, which is favorable for the insertion/extraction of Li＋.
基金Project(2013AA050901)supported by the National High-tech Research and Development Program of China
文摘In order to enhance electrochemical properties of LiFePO4 （LFP） cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The results show that the spherical precursors with the sizes of 0.5-5 μm can be completely converted to LFP/C when the calcination temperature is higher than 500 ℃. The LFP/C microspheres obtained at calcination temperature of 700 ℃ are composed of numerous particles with sizes of -20 nm, and have well-developed interconnected pore structure and large specific surface area of 28.77 mE/g. The specific discharge capacities of the LFP/C obtained at 700 ℃ are 162.43, 154.35 and 144.03 mA.h/g at 0.5C, 1C and 2C, respectively. Meanwhile, the capacity retentions can reach up to 100% after 50 cycles. The improved electrochemical properties of the materials are ascribed to a small Li＋ diffusion resistance and special structure of LFP/C microspheres.
基金supported by Natural Science of Guangxi(No.0991025)Program for Excellent Talents in Guangxi Higher Education Institutions(GuiJiaoRen[No.2010]65)+5 种基金National Natural Science Foundation of China(No.51164007)Innovation Project of Guangxi Graduate EducationEducational Commission of Guangxi(No.201101ZD008)the Important National Science&Technology Specific(No.2008ZX07317-02-03E)the Key Science Research of Ministry of Education of the Pepople's Republic of China(GuiKeGong0092008)the Provincial Natural Science Foundation of Guangxi
文摘LiMnPO_4 /C composites were synthesized via solid-state reaction with different carbon sources: sucrose, citric acid and oxalic acid. The sam- ples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical performance test. The results of XRD reveal that carbon coating has no effect on the phase of LiMnPO_4 . The LiMnPO_4 /C synthesized at 600 °C with citric acid as carbon source shows an initial discharge capacity of 117.8 mA·hg^-1 at 0.05 C rate. After 30 cycles, the capacity remains 98.2 mAh·g^-1 . The improved electrochemical properties of LiMnPO_4 /C is attributed to the decomposition of organic acid during the sintering process.
基金supported by the National Projects of NSFC(21322101 and 21231005)MOE(B12015 and IRT13R30)
文摘LiNiCoAlO（NCA） with Zr（OH）coating is demonstrated as high performance cathode material for lithium ion batteries（LIBs）. The coated materials are synthesized via a simple dry coating method of NCA with Zr（OH）powders, and then characterized with scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and X-ray photoelectron spectroscopy（XPS）. Experimental results show that amorphous Zr（OH）powders have been successfully coated on the surface of spherical NCA particles, exhibiting improved electrochemical performance. 0.50 wt% Zr（OH）coated NCA delivers a capacity of 197.6 mAh/g at the first cycle and 154.3 mAh/g after 100 cycles with a capacity retention of 78.1% at 1 C rate. In comparison, the pure NCA shows a capacity of 194.6 mAh/g at the first cycle and 142.5 mAh/g after 100 cycles with a capacity retention of 73.2% at 1 C rate. Electrochemical impedance spectroscopy（EIS） results show that the coated material exhibits a lower resistance, indicating that the coating layer can efficiently suppress transition metals dissolution and decrease the side reactions at the surface between the electrode and electrolyte. Therefore, surface coating with amorphous Zr（OH）is a simple and useful method to enhance the electrochemical performance of NCA-based materials for the cathode of LIBs.
基金supported by the Singapore Centre for 3D Printing which is funded by the Singapore National Research Foundation.
文摘The rapid development of additive manufacturing and advances in shape memory materials have fueled the progress of four-dimensional （4D） printing. With the right external stimulus, the need for human interaction, sensors, and batteries will be eliminated, and by using additive manufacturing, more complex devices and parts can be produced. With the current understanding of shape memory mechanisms and with improved design for additive manufacturing, reversibility in 4D printing has recently been proven to be feasible. Conventional one-way 4D printing requires human interaction in the programming （or shapesetting） phase, but reversible 4D printing, or two-way 4D printing, will fully eliminate the need for human interference, as the programming stage is replaced with another stimulus. This allows reversible 4D printed parts to be fully dependent on external stimuli; parts can also be potentially reused after every recovery, or even used in continuous cycles-an aspect that carries industrial appeal. This paper presents a review on the mechanisms of shape memory materials that have led to 4D printing, current findings regarding 4D printing in alloys and polymers, and their respective limitations. The reversibility of shape memory materials and their feasibility to be fabricated using three-dimensional （3D） printing are summarized and critically analyzed. For reversible 4D printing, the methods of 3D printing, mechanisms used for actuation, and strategies to achieve reversibility are also highlighted. Finally, prospective future research directions in reversible 4D printing are suggested.
基金supported by National Key Technology R&D Program of China(No.2007BAE12B01-1)Science and Technology Planning Program of Hunan Province,China(No.2008GK3015)
文摘A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-type Li2FeSiO4 sample with uniform and fine particle sizes is successfully and fast synthesized by microwave heating at 700 ℃ in 12 rain. And the obtained Li2FeSiO4 materials show better electrochemical performance and microstructure than those of Li2FeSiO4 sample by the conventional solidstate reaction. ？2009 Yan Bing Cao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金supported by the National Natural Science Foundation of China (No.21007014, 21107024)the Start Foundation of Hunan Agricultural University (No.10YJ01)+2 种基金the National Science and Technology Major Projects (No.2009ZX07212-001-05)the National Environmental Protection Public Welfare Program (No.201009047)the Scientific Research Fund of Hunan Provincial Education Department (No.11C0650)
文摘La-EDTA-Fe3O4 was prepared by a chemical co-precipitation method. The magnetic composite was characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT-IR）. Furthermore, the adsorption properties of La-EDTA-Fe3O4 toward phosphate in water were investigated. The uptake rate of phosphate in water by La-EDTA-Fe3O4 was 3-1000 times than that of EDTA-Fe3O4, and reached 97.8% at 7 hr. The adsorption process agreed well with the Freundlich model and kinetics studies showed that the adsorption of phosphate proceeds according to pseudo second-order adsorption kinetics. The maximum removal rate was achieved at pH 6.0-7.0. The La-EDTA-Fe3O4 had good adsorption properties and could be separated well from aqueous solution by a permanent magnet. Therefore, this nanomaterial has potential application for the removal of phosphate from large water bodies.
基金financially supported by the National Natural Science Foundation of China (Nos. 21231005 and 51071087)the Major State Basic Research Development Program of China(Nos. 2011CB935900 and 2010CB631303)+2 种基金the Discipline Innovative Engineering Plan (B12015)the Research Fund for the Doctoral Program of Higher Education of China (No.20120031110001)the Tianjin Science & Technology Project (No. 10SYSYJC27600)
文摘Monocrystal LiMn_(0. 6)Fe_(0. 4)PO_4 cathode material was obtained via hydrothermal method at 180℃ for 10 h without any surfactant. The effects of hydrothermal time on the phase and morphology of the material were discussed.By controlling the reaction solutions, the rodlike, flowerlike,and strawlike LiMn_(0.6)Fe_(0.4)PO_4 cathode materials were synthesized. Electrochemical performances show that the rodlike LiMn_(0. 6)Fe_(0. 4)PO_4 has the best electrochemical properties. The initial discharge capacity of the rodlike structure is 106.4 mAh·g^(-1), which is higher than those of flowerlike and strawlike materials.
基金This work was financially supported by the National Natural Science Foundation of China (No.50134020)
文摘Spherical LiFePO4 and LiFePO4/C composite powders for lithium ion batteries were synthesized by a novel processing route of co-precipitation and subsequent calcinations in a nitrogen and hydrogen atmosphere. The precursors of LiFePO4, LiFePO4/C composite and the resultant products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and the electrochemical performances were investigated by galvanostatic charge and discharge tests. The precursors composed of amorphous Fe3(PO4)2·xH2O and crystalline Li3PO4 obtained in the co-precipitation processing have a sphere-like morphology. The spherical LiFePO4 derived from the calcinations of the precursor at 700 ℃ for 10 h in a reduction atmosphere shows a discharge capacity of 119 mAh·g-1 at the C/10 rate, while the LiFePO4/C composite with 10wt.% carbon addition exhibits a discharge capacity of 140 mAh·g-1. The electrochemical performances indicate that the LiFePO4/C composite has a higher specific capacity and a more stable cycling performance than the bare olivine LiFePO4 due to the carbon addition enhancing the electronic conductivity.
基金supported by the National Natural Science Foundation of China (Grand No. 50872032)the financial support from the Hundred Talents Program of the Chinese Academy of Sciencesthe National Basic Research Program of China(Grant No. 2010CB631006)
文摘Micro-sized（1030.3±178.4 nm） and nano-sized（50.4±8.0 nm） Fe3O4 particles have been fabricated through hydrogen thermal reduction of α-Fe2O3 particles synthesized by means of a hydrothermal process.The morphology and microstructure of the micro-sized and the nano-sized Fe3O4 particles were characterized by X-ray diffraction,field-emission gun scanning electron microscopy,transmission electron microscopy and highresolution electron microscopy.The micro-sized Fe3O4 particles exhibit porous structure,while the nano-sized Fe3O4 particles are solid structure.Their electrochemical performance was also evaluated.The nano-sized solid Fe3O4 particles exhibit gradual capacity fading with initial discharge capacity of 1083.1 mAhg-1 and reversible capacity retention of 32.6% over 50 cycles.Interestingly,the micro-sized porous Fe3O4 particles display very stable capacity-cycling behavior,with initial discharge capacity of 887.5 mAhg-1 and charge capacity of 684.4 mAhg-1 at the 50th cycle.Therefore,77.1% of the reversible capacity can be maintained over 50 cycles.The micro-sized porous Fe3O4 particles with facile synthesis,good cycling performance and high capacity retention are promising candidate as anode materials for high energy-density lithium-ion batteries.
基金the financial support from the National Natural Science Foundation of China(22109021)Natural Science Foundation of Jiangsu Province(BK20200375)Jiangsu Shuangchuang Talent Program(JSSCBS20210100)。
文摘Four-dimensional printing allows for the transformation capabilities of 3D-printed architectures over time,altering their shape,properties,or function when exposed to external stimuli.This interdisciplinary technology endows the 3D architectures with unique functionalities,which has generated excitement in diverse research fields,such as soft robotics,biomimetics,biomedical devices,and sensors.Understanding the selection of the material,architectural designs,and employed stimuli is crucial to unlocking the potential of smart customization with 4D printing.This review summarizes recent significant developments in 4D printing and establishes links between smart materials,3D printing techniques,programmable structures,diversiform stimulus,and new functionalities for multidisciplinary applications.We start by introducing the advanced features of 4D printing and the key technological roadmap for its implementation.We then place considerable emphasis on printable smart materials and structural designs,as well as general approaches to designing programmable structures.We also review stimulus designs in smart materials and their associated stimulus-responsive mechanisms.Finally,we discuss new functionalities of 4D printing for potential applications and further development directions.
文摘LiFePO4/Carbon composite cathode material was prepared using starch as carbon source by spray-pelleting and subsequent pyrolysis in N2. The samples were characterized by XRD, SEM, Raman, and their electrochemical performance was investigated in terms of cycling behavior. There has a special micro-morphology via the process, which is favorable to electrochemical properties. The discharge capacity of the LiFePO4.C composite was 170 mAh g-1, equal to the theoretical specific capacity at 0.1 C rate. At 4 C current density, the specific capacity was about 80 mAh g-1, which can satisfy for transportation applications if having a more flat discharge flat.
