The development of aqueous zinc ion battery cathode materials with high capacity and high magnification is still a challenge.Herein,porous vanadium oxide/carbon(p-VO_(x)@C,mainly VO_(2) with a small amount of V_(2)O_(...The development of aqueous zinc ion battery cathode materials with high capacity and high magnification is still a challenge.Herein,porous vanadium oxide/carbon(p-VO_(x)@C,mainly VO_(2) with a small amount of V_(2)O_(3)) core/shell microspheres with oxygen vacancies are facilely fabricated by using a vanadium-based metal-organic framework(MIL-100(V)) as a sacrificial template.This unique structure can improve the conductivity of the VO_(x),accelerate electrolyte diffusion,and suppress structural collapse during circulation.Subsequently,H_(2)O molecules are introduced into the interlayer of VO_(x) through a highly efficient in-situ electrochemical activation process,facilitating the intercalation and diffusion of zinc ions.After the activation,an optimal sample exhibits a high specific capacity of 464.3 mA h g^(-1) at0.2 A g^(-1) and 395.2 mA h g^(-1) at 10 A g^(-1),indicating excellent rate performance.Moreover,the optimal sample maintains a capacity retention of about 89.3% after 2500 cycles at 10 A g^(-1).Density functional theory calculation demonstrates that the presence of oxygen vacancies and intercalated water molecules can significantly reduce the diffusion barrier for zinc ions.In addition,it is proved that the storage of zinc ions in the cathode is achieved by reversible intercalation/extraction during the charge and discharge process through various ex-situ analysis technologies.This work demonstrates that the p-VO_(x)@C has great potential for applications in aqueous ZIBs after electrochemical activation.展开更多
Na-ion O3-type layered oxides are prospective cathodes for Na-ion batteries due to high energy density and low-cost.Nevertheless,such cathodes usually suffer from phase transitions,sluggish kinetics and air instabilit...Na-ion O3-type layered oxides are prospective cathodes for Na-ion batteries due to high energy density and low-cost.Nevertheless,such cathodes usually suffer from phase transitions,sluggish kinetics and air instability,making it difficult to achieve high performance solid-state sodium-ion batteries.Herein,the high-entropy design and Li doping strategy alleviate lattice stress and enhance ionic conductivity,achieving high-rate performance,air stability and electrochemically thermal stability for Na_(0.95)Li_(0.06)Ni_(0.25)Cu_(0.05)Fe_(0.15)Mn_(0.49)O_(2).This cathode delivers a high reversible capacity(141 mAh g^(−1)at 0.2C),excellent rate capability(111 mAh g^(−1)at 8C,85 mAh g^(−1)even at 20C),and long-term stability(over 85%capacity retention after 1000 cycles),which is attributed to a rapid and reversible O3–P3 phase transition in regions of low voltage and suppresses phase transition.Moreover,the compound remains unchanged over seven days and keeps thermal stability until 279℃.Remarkably,the polymer solid-state sodium battery assembled by this cathode provides a capacity of 92 mAh g^(−1)at 5C and keeps retention of 96%after 400 cycles.This strategy inspires more rational designs and could be applied to a series of O3 cathodes to improve the performance of solid-state Na-ion batteries.展开更多
As a promising cathode material,Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)has attracted wide attention for sodium-ion batteries(SIBs)because of its high operating voltage and high structural stability.However,the low intrinsi...As a promising cathode material,Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)has attracted wide attention for sodium-ion batteries(SIBs)because of its high operating voltage and high structural stability.However,the low intrinsic electronic conductivity and insufficient Na ion mobility of NVPF limit its development.Herein,K-doping NVPF is prepared through a facile ball-milling combined calcination method.The effects of K-doping on the crystal structure,kinetic properties and electrochemical performance are investigated.The results demonstrate that the Na_(2.90)K_(0.10)V_(2)(PO_(4))_(3)F_(3)(K0.10-NVPF)exhibits a high capacity(120.8 mAh g^(-1) at 0.1 C),high rate capability(66 mAh g^(-1) at 30 C)and excellent cycling performance(a capacity retention of 97.5%at 1 C over 500 cycles).Also,the occupation site of K ions in the lattice,electronic band structure and Na-ion transport kinetic property in K-doped NVPF are investigated by density functional theory(DFT)calculations,which reveals that the K-doped NVPF exhibits improved electronic and ionic conductivities,and located K^(+) ions in the lattice to contribute to high reversible capacity,rate capability and cycling stability.Therefore,the K-doped NVPF serves as a promising cathode material for high-energy and high-power SIBs.展开更多
The searching of highly efficient catalysts for oxygen reduction reaction(ORR) has attracted particular attention. In this work, we construct the graphene-based bilayers BG/X that consists by the CoN_(4) embedded grap...The searching of highly efficient catalysts for oxygen reduction reaction(ORR) has attracted particular attention. In this work, we construct the graphene-based bilayers BG/X that consists by the CoN_(4) embedded graphene as the upper layer and the X modified graphene as the bottom layer(X = Si, P, S). The interfacial bonding between CoN_(4) site and the X dopant is spontaneously formed due to the strong pd hybridization, which changes the Co ligand from the planar-four N_(4) coordination into spatial-five N_(4)+X one. The additive glue atom weakens too strong adsorptions of the ORR intermediates on CoN_(4) site and thereby improves the ORR activities in comparison with the monolayer counterpart. From the free energy profiles, the overpotentials η are 0.47, 0.49 and 0.45 V for BG/Si_(a), BG/P_(a) and BG/S_(a), respectively,being comparable to that of state-of-the-art Pt material. Besides, the kinetic barriers for the bilayers are less than 0.75 eV, an indicative of the room temperature activity. Furthermore, the combination of thermodynamic and kinetic analysis ensures the preference of 4e^(-)-OOH associative mechanism over 2e^(-)-H_(2)O_(2) mechanism, being beneficial for membrane stability against the H_(2)O_(2) corrosion. Therefore,the graphene-based bilayers deliver the high efficiencies for oxygen reduction electrocatalysis.Therefore, the interfacial bonding in the graphene-based bilayers provides an interesting strategy to suppress the poisoning phenomenon for the material design from atom scale.展开更多
Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M...Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M=Ti,Zr,Hf,Nb,Ta) was found to be distributed relatively uniform in the composite ceramic.The oxidation behavior of the ceramic was examined after exposure to 923 K and 1173 K.Morphology of the surface and cross sections of all oxidation samples were observed.The characteristics of the oxidation behavior of the high-entropy carbide and the secondary phase M_(x)C were compared and analyzed.The secondary phases(such as Ti-rich carbide or Hf-rich carbide) in the material were seriously oxidized at 923 K and 1173 K,which reflects the superior oxidation performance of the high-entropy carbide.The nano high-entropy oxides with Ti,Zr,Hf,Nb,Ta,and O elements were discovered by oxidation of the composite ceramic.This research will help deepen the understanding of the oxidation mechanism of high-entropy carbide and composite ceramic.展开更多
Ultrasonic Assisted SILAR method (UA-SILAR) was developed and highly oriented ZnO films were deposited on the glass substrate by this novel technique. The crystallinity and microstructure of as-deposited ZnO films wer...Ultrasonic Assisted SILAR method (UA-SILAR) was developed and highly oriented ZnO films were deposited on the glass substrate by this novel technique. The crystallinity and microstructure of as-deposited ZnO films were analyzed by means of XRD and SEM. Moreover, the underling deposition mechanism of ZnO films was discussed. Results show that obtained ZnO films exhibit an excellent crystallinity with the preferential orientation of (002) plane. The crystalline grain of films is about 40nm in size, which is supported by both the Sherrer equation and the SEM result. However, the ZnO film is composed of numerous clustered particulates in the size of 200 to 300nm, and each particulate is the compact aggregation of smaller ZnO crystalline grains. It is speculated that the excellent crystallinity of ZnO films may chiefly originate from the cavatition effect of the ultrasonic rinsing process.展开更多
With the wide using of transparent alumina ceramics and synthetic sapphire,the demand of the furnace for them is promoted steadily,and the furnace lining materials are upgrading. Having low thermal conductivity and th...With the wide using of transparent alumina ceramics and synthetic sapphire,the demand of the furnace for them is promoted steadily,and the furnace lining materials are upgrading. Having low thermal conductivity and the same composition with transparent alumina ceramics and sapphire,porous alumina ceramics with high purity are expected to lower the high energy consumption without contamination. In this paper,porous alumina ceramics with porosity of 75. 3%- 81. 9% and impurity less than 0. 1% were prepared by a foaming method combined with gelcasting,using high purity alumina powders as raw materials. By changing the amount of foaming agent and the solid content,the microstructure and properties of porous ceramics were tailored. The compressive strength of the porous ceramics ranged from( 22. 4 ± 2. 5) MPa to( 48. 1 ± 3. 1) MPa,the thermal conductivity of porous ceramics at 1 000 ℃ ranged between 0. 41- 0. 65 W·( m·K)^(-1).展开更多
In this work,Yb2O3 and Mg O were used as sintering aids in preparing silicon nitride ceramics by gas pressure sintering( 0. 6 MPa N2atmosphere) to investigate how the amounts of Yb2O3- Mg O influence the mechanical pr...In this work,Yb2O3 and Mg O were used as sintering aids in preparing silicon nitride ceramics by gas pressure sintering( 0. 6 MPa N2atmosphere) to investigate how the amounts of Yb2O3- Mg O influence the mechanical properties and thermal conductivity of silicon nitride ceramics. The total contents of Yb2O3- Mg O added were 1 mol%,2 mol%,4 mol%,6 mol%,8 mol%,10 mol%,12 mol%,14 mol%,keeping the Yb2O3-Mg O molar ratio of 1 ∶ 1 steadily. Curves of the relative density,thermal conductivity and bending strength plotted against the aids content present a ‘mountain'shape with a maximum at nearly 10 mol% aids. The fracture toughness increased with the amounts of additives up to10 mol% and decreased slightly thereafter. The mechanical properties and thermal conductivity were almost proportional to the amount of the additives before10 mol%. When the content of aids exceeded 10 mol%,it would weaken the mechanical properties and thermal conductivity of the ceramics. The optimum content of Yb2O3- Mg O was 10 mol% by gas pressure sintering( 0. 6MPa) at 1 850 ℃ for 4 h,which led to a relative density of 98. 9%,a flexural strength of( 966 ± 38)MPa as well as a fracture toughness of( 6. 29 ± 0. 29)MPa·m1 /2and thermal conductivity of 82 W /( m·K).展开更多
Solid-state batteries represent the future of energy storage technology,offering improved safety and energy density.Garnet-type Li7La3Zr2O12(LLZO)solidstate electrolytes-based solid-state lithium batteries(SSLBs)stand...Solid-state batteries represent the future of energy storage technology,offering improved safety and energy density.Garnet-type Li7La3Zr2O12(LLZO)solidstate electrolytes-based solid-state lithium batteries(SSLBs)stand out for their appealingmaterial properties and chemical stability.Yet,their successful deployment depends on conquering interfacial challenges.This review article primarily focuses on the advancement of interfacial engineering for LLZO-based SSLBs.We commence with a concise introduction to solid-state electrolytes and a discussion of the challenges tied to interfacial properties in LLZO-based SSLBs.We deeply explore the correlations between structure and properties and the design principles vital for achieving an ideal electrode/electrolyte interface.Subsequently,we delve into the latest advancements and strategies dedicated to overcoming these challenges,with designated sections on cathode and anode interface design.In the end,we share our insights into the advancements and opportunities for interface design in realizing the full potential of LLZO-based SSLBs,ultimately contributing to the development of safe and high-performance energy storage solutions.展开更多
The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathod...The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathode catalysts with high activity and stability is crucial to overcome the terrible issues at high current density.Herein,we report a surface engineering strategy to adjust the surface electron structure of boron(B)‐doped PtNi nanoalloy on carbon nanotubes(PtNiB@CNTs)as an efficient bifunctional cathodic catalyst for high‐rate and long‐life Li‐O2 batteries.Notably,the Li‐O2 batteries assembled with as‐prepared PtNiB@CNT catalyst exhibit ultrahigh discharge capacity of 20510 mA·h/g and extremely low overpotential of 0.48 V at a high current density of 1000 mA/g,both of which outperform the most reported Pt‐based catalysts recently.Meanwhile,our Li‐O2 batteries offer excellent rate capability and ultra‐long cycling life of up to 210 cycles at 1000 mA/g under a fixed capacity of 1000 mA·h/g,which is two times longer than those of Pt@CNTs and PtNi@CNTs.Furthermore,it is revealed that surface engineering of PtNi nanoalloy via B doping can efficiently tailor the electron structure of nanoalloy and optimize the adsorption of oxygen species,consequently delivering excellent Li‐O2 battery performance.Therefore,this strategy of regulating the nanoalloy by doping nonmetallic elements will pave an avenue for the design of high‐performance catalysts for metal‐oxygen batteries.展开更多
The garnet-type Li7La3Zr2O12 ceramic is a promising solid electrolyte for all-solid-state secondary lithium batteries. However, it faces the problem of lithium volatilization during sintering, which may cause low dens...The garnet-type Li7La3Zr2O12 ceramic is a promising solid electrolyte for all-solid-state secondary lithium batteries. However, it faces the problem of lithium volatilization during sintering, which may cause low density and deterioration of ionic conductivity. In this work, the effects of sintering temperature and addition on the density as well as the lithium ion conductivity of Li7-xLa3Zr2-xTaxO12 (LLZTO, x=0.25) ceramics prepared by solid state reaction have been studied. It is found that optimization of the sintering temperature leads to a minor increase in the ceramic density, yielding an optimum ionic conductivity of 2.9×10-4 S·cm-1 at 25℃. Introduction of Li 3 PO 4 addition in an appropriate concentration can obviously increase the density, leading to an optimum ionic conductivity of 7.2×10-4 S·cm-1 at 25℃. This value is superior to the conductivity data in most recent reports on the LLZTO ceramics.展开更多
A series of N-doped carbon materials(NCs)were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile onestep pyrolysis method. The characterization of microstructural featur...A series of N-doped carbon materials(NCs)were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile onestep pyrolysis method. The characterization of microstructural features shows that the NCs samples are composed of few-layered graphene-like nanoflakes with controlled in situ N doping, which is attributed to the confined pyrolysis of citric acid within the interlayers of the dicyandiamide-derived g-C_3N_4 with high nitrogen contents. Evidently, the pore volumes of the NCs increased with the increasing content of dicyandiamide in the precursor. Among these samples, the NCs nanoflakes prepared with the citric acid/dicyandiamide mass ratio of 1:6, NC-6,show the highest N content of ~6.2 at%, in which pyridinic and graphitic N groups are predominant. Compared to the commercial Pt/C catalyst, the as-prepared NC-6 exhibits a small negative shift of ~66 mV at the half-wave potential, demonstrating excellent electrocatalytic activity in the oxygen reduction reaction. Moreover, NC-6 also shows better long-term stability and resistance to methanol crossover compared to Pt/C. The efficient and stable performance are attributed to the graphene-like microstructure and high content of pyridinic and graphitic doped nitrogen in the sample, which creates more active sites as well as facilitating charge transfer due to the close four-electron reaction pathway. The superior electrocatalytic activity coupled with the facile synthetic method presents a new pathway to cost-effective electrocatalysts for practical fuel cells or metal–air batteries.展开更多
Early surgical resection and chemotherapy of bone cancer are commonly used in the treatment of bone tumor,but it is still highly challenging to prevent recurrence and fill the bone defect caused by the resection site....Early surgical resection and chemotherapy of bone cancer are commonly used in the treatment of bone tumor,but it is still highly challenging to prevent recurrence and fill the bone defect caused by the resection site.In this work,we report a rational integration of photonic-responsive two-dimensional(2D)ultrathin niobium carbide(Nb2C)MXene nanosheets(NSs)into the 3D-printed bone-mimetic scaffolds(NBGS)for osteosarcoma treatment.The integrated 2D Nb2C-MXene NSs feature specific photonic response in the second near-infrared(NIR-II)biowindow with high tissue-penetrating depth,making it highly efficient in killing bone cancer cells.Importantly,Nb-based species released by the biodegradation of Nb2C MXene can obviously promote the neogenesis and migration of blood vessels in the defect site,which can transport more oxygen,vitamins and energy around the bone defect for the reparative process,and gather more immune cells around the defect site to accelerate the degradation of NBGS.The degradation of NBGS provides sufficient space for the bone remodeling.Besides,calcium and phosphate released during the degradation of the scaffold can promote the mineralization of new bone tissue.The intrinsic multifunctionality of killing bone tumor cell and promoting angiogenesis and bone regeneration makes the engineered Nb2C MXeneintegrated composite scaffolds a distinctive implanting biomaterial on the efficient treatment of bone tumor.展开更多
As for ceramic stereolithography technique,the preparation of suitable resin-based ceramic slurry is of primary importance.In this study,the effects of powder characteristics such as specific surface area,particle siz...As for ceramic stereolithography technique,the preparation of suitable resin-based ceramic slurry is of primary importance.In this study,the effects of powder characteristics such as specific surface area,particle size and distribution,particle morphology on the rheological behavior of zirconia resin-based suspensions were investigated intensively.Results show that the specific surface area of the powder is the most important factor affecting slurry viscosity.Choosing low specific surface area and quasi-spherical shaped powder is more likely to obtain low viscosity slurries.In addition,the influence of solid loading on the flow behavior were also studied using Krieger-Dougherty model.Zirconia samples with the relative density of(97.83±0.33)%were obtained after sintering at 1550℃.No obvious abnormal grain growth in the microstructure of the sintered body is observed.Results indicate that after the optimization of the processing parameters with the help of rheology characterization,complex-shaped high-quality zirconia parts can be obtained using the stereolithography technique.展开更多
Eu^2＋-doped Ba3Si6012N2 green phosphors were prepared by microwave assisted sintering method at 1275℃ for 4 h, while the counterparts using conventional solid-state reaction method were synthesized at temperature hi...Eu^2＋-doped Ba3Si6012N2 green phosphors were prepared by microwave assisted sintering method at 1275℃ for 4 h, while the counterparts using conventional solid-state reaction method were synthesized at temperature higher than 1300℃ and for to 10 h. Microwave assisted sintering could reduce the activation energy and enhance the diffu- sion rate, thus greatly improved the sintering. Moreover, the influence of Si3N4 content on phase formation, morphol- ogy, absorption, and quantum efficiency, and photoluminescence properties of phosphors were studied. As a result, the Ba3Si6OI2N2：Eu^2＋ samples sintered by microwave assisted sintering method have a higher phase purity and photo- luminescence intensity under ultraviolet excitation as compared with samples sintered in the conventional tube furnace The proposed method is a potential preparation method for the oxynitride phosphors with strong photoluminescence and high phase purity.展开更多
As essential electrochromic(EC) materials are related to energy savings in fenestration technology,tungsten oxide(WO3) films have been intensively studied recently.In order to achieve better understanding of the mecha...As essential electrochromic(EC) materials are related to energy savings in fenestration technology,tungsten oxide(WO3) films have been intensively studied recently.In order to achieve better understanding of the mechanism of EC properties,and thus facilitate optimization of device performance,clarification of the correlation between cation storage and transfer properties and the coloration performance is needed.In this study,transparent polycrystalline and amorphous WO3 thin films were deposited on SnO2:F-coated glass substrates by the pulsed laser deposition technique.Investigation into optical transmittance in a wavelength range of 400-800 nm measured at a current density of 130 μA·cm-2 with the applied potential ranging from 3.2 to 2.2 V indicates that polycrystalline films have a larger optical modulation of ～ 30% at 600 nm and a larger coloration switch time of 95 s in the whole wavelength range compared with amorphous films(～ 24% and 50 s).Meanwhile,under the same conditions,polycrystalline films show a larger lithium storage capacity corresponding to a Li/W ratio of 0.5,a smaller lithium diffusion coefficient(2×10-12cm2·s-1 for Li/W=0.24) compared with the amorphous ones,which have a Li/W ratio of 0.29 and a coefficient of ～2.5×10-11cm2·s-1 as Li/W=0.24.These results demonstrate that the large optical modulation relates to the large lithium storage capacity,and the fast coloration transition is associated with fast lithium diffusion.展开更多
The title new compounds with chemical formula RE CuBi2 were synthesized by arc melting method followed by annealing. The crystal structures refined using Rietveld method and X-ray powder diffraction data show to be is...The title new compounds with chemical formula RE CuBi2 were synthesized by arc melting method followed by annealing. The crystal structures refined using Rietveld method and X-ray powder diffraction data show to be isotypic to CaMnBi2 structure type with space group P4/nmm（No.129）. The unit cell parameters are a=（0.457946（4）nm）,c=0.98858（2）nm, V=0.207319（8）nm3 for LaCuBi2, a=0.449279（9）nm, c= 0.95958（4）nm, V= 0.19369（2）nm3 for GdCuBi2 and a=0.447680（7）nm, c=0.95124（3）nm,V=0.190644（5）nm3 for DyCuBi2 respectively, showing lanthanide contraction. The structure is characterized by layers of edge-shearing CuBi4 tetrahedron and covalently bonded Bi square net separated by rare earth atoms.展开更多
基金supported by the National Natural Science Foundation of China(Nos.92163118,51972234)。
文摘The development of aqueous zinc ion battery cathode materials with high capacity and high magnification is still a challenge.Herein,porous vanadium oxide/carbon(p-VO_(x)@C,mainly VO_(2) with a small amount of V_(2)O_(3)) core/shell microspheres with oxygen vacancies are facilely fabricated by using a vanadium-based metal-organic framework(MIL-100(V)) as a sacrificial template.This unique structure can improve the conductivity of the VO_(x),accelerate electrolyte diffusion,and suppress structural collapse during circulation.Subsequently,H_(2)O molecules are introduced into the interlayer of VO_(x) through a highly efficient in-situ electrochemical activation process,facilitating the intercalation and diffusion of zinc ions.After the activation,an optimal sample exhibits a high specific capacity of 464.3 mA h g^(-1) at0.2 A g^(-1) and 395.2 mA h g^(-1) at 10 A g^(-1),indicating excellent rate performance.Moreover,the optimal sample maintains a capacity retention of about 89.3% after 2500 cycles at 10 A g^(-1).Density functional theory calculation demonstrates that the presence of oxygen vacancies and intercalated water molecules can significantly reduce the diffusion barrier for zinc ions.In addition,it is proved that the storage of zinc ions in the cathode is achieved by reversible intercalation/extraction during the charge and discharge process through various ex-situ analysis technologies.This work demonstrates that the p-VO_(x)@C has great potential for applications in aqueous ZIBs after electrochemical activation.
基金National Natural Science Foundation of China(52202327)Science and Technology Commission of Shanghai Municipality(22ZR1471300)+2 种基金National Science Foundation of China(Grant 51972326)Youth Innovation Promotion Association CAS,Foundation Strengthening ProjectProgram of Shanghai Academic Research Leader(Grant 22XD1424300).
文摘Na-ion O3-type layered oxides are prospective cathodes for Na-ion batteries due to high energy density and low-cost.Nevertheless,such cathodes usually suffer from phase transitions,sluggish kinetics and air instability,making it difficult to achieve high performance solid-state sodium-ion batteries.Herein,the high-entropy design and Li doping strategy alleviate lattice stress and enhance ionic conductivity,achieving high-rate performance,air stability and electrochemically thermal stability for Na_(0.95)Li_(0.06)Ni_(0.25)Cu_(0.05)Fe_(0.15)Mn_(0.49)O_(2).This cathode delivers a high reversible capacity(141 mAh g^(−1)at 0.2C),excellent rate capability(111 mAh g^(−1)at 8C,85 mAh g^(−1)even at 20C),and long-term stability(over 85%capacity retention after 1000 cycles),which is attributed to a rapid and reversible O3–P3 phase transition in regions of low voltage and suppresses phase transition.Moreover,the compound remains unchanged over seven days and keeps thermal stability until 279℃.Remarkably,the polymer solid-state sodium battery assembled by this cathode provides a capacity of 92 mAh g^(−1)at 5C and keeps retention of 96%after 400 cycles.This strategy inspires more rational designs and could be applied to a series of O3 cathodes to improve the performance of solid-state Na-ion batteries.
基金financially funded by the Regional Innovation and Development Joint Fund,National Natural Science Foundation of China(No.U20A20249)National Key Research Program of China(No.2016YFB0901500)。
文摘As a promising cathode material,Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)has attracted wide attention for sodium-ion batteries(SIBs)because of its high operating voltage and high structural stability.However,the low intrinsic electronic conductivity and insufficient Na ion mobility of NVPF limit its development.Herein,K-doping NVPF is prepared through a facile ball-milling combined calcination method.The effects of K-doping on the crystal structure,kinetic properties and electrochemical performance are investigated.The results demonstrate that the Na_(2.90)K_(0.10)V_(2)(PO_(4))_(3)F_(3)(K0.10-NVPF)exhibits a high capacity(120.8 mAh g^(-1) at 0.1 C),high rate capability(66 mAh g^(-1) at 30 C)and excellent cycling performance(a capacity retention of 97.5%at 1 C over 500 cycles).Also,the occupation site of K ions in the lattice,electronic band structure and Na-ion transport kinetic property in K-doped NVPF are investigated by density functional theory(DFT)calculations,which reveals that the K-doped NVPF exhibits improved electronic and ionic conductivities,and located K^(+) ions in the lattice to contribute to high reversible capacity,rate capability and cycling stability.Therefore,the K-doped NVPF serves as a promising cathode material for high-energy and high-power SIBs.
基金the supports from the National Natural Science Foundation of China (51701152, 21503097, 51631004, 21806023, 51702345)Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX20_3160)。
文摘The searching of highly efficient catalysts for oxygen reduction reaction(ORR) has attracted particular attention. In this work, we construct the graphene-based bilayers BG/X that consists by the CoN_(4) embedded graphene as the upper layer and the X modified graphene as the bottom layer(X = Si, P, S). The interfacial bonding between CoN_(4) site and the X dopant is spontaneously formed due to the strong pd hybridization, which changes the Co ligand from the planar-four N_(4) coordination into spatial-five N_(4)+X one. The additive glue atom weakens too strong adsorptions of the ORR intermediates on CoN_(4) site and thereby improves the ORR activities in comparison with the monolayer counterpart. From the free energy profiles, the overpotentials η are 0.47, 0.49 and 0.45 V for BG/Si_(a), BG/P_(a) and BG/S_(a), respectively,being comparable to that of state-of-the-art Pt material. Besides, the kinetic barriers for the bilayers are less than 0.75 eV, an indicative of the room temperature activity. Furthermore, the combination of thermodynamic and kinetic analysis ensures the preference of 4e^(-)-OOH associative mechanism over 2e^(-)-H_(2)O_(2) mechanism, being beneficial for membrane stability against the H_(2)O_(2) corrosion. Therefore,the graphene-based bilayers deliver the high efficiencies for oxygen reduction electrocatalysis.Therefore, the interfacial bonding in the graphene-based bilayers provides an interesting strategy to suppress the poisoning phenomenon for the material design from atom scale.
基金Project supported by the Doctoral Research Fund of Southwest University of Science and Technology(Grant No.20zx7104)the Sichuan Science and Technology Program(Grant No.2020ZYD055)the National Natural Science Foundation of China(Grant Nos.11905206 and 12075194)。
文摘Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M=Ti,Zr,Hf,Nb,Ta) was found to be distributed relatively uniform in the composite ceramic.The oxidation behavior of the ceramic was examined after exposure to 923 K and 1173 K.Morphology of the surface and cross sections of all oxidation samples were observed.The characteristics of the oxidation behavior of the high-entropy carbide and the secondary phase M_(x)C were compared and analyzed.The secondary phases(such as Ti-rich carbide or Hf-rich carbide) in the material were seriously oxidized at 923 K and 1173 K,which reflects the superior oxidation performance of the high-entropy carbide.The nano high-entropy oxides with Ti,Zr,Hf,Nb,Ta,and O elements were discovered by oxidation of the composite ceramic.This research will help deepen the understanding of the oxidation mechanism of high-entropy carbide and composite ceramic.
文摘Ultrasonic Assisted SILAR method (UA-SILAR) was developed and highly oriented ZnO films were deposited on the glass substrate by this novel technique. The crystallinity and microstructure of as-deposited ZnO films were analyzed by means of XRD and SEM. Moreover, the underling deposition mechanism of ZnO films was discussed. Results show that obtained ZnO films exhibit an excellent crystallinity with the preferential orientation of (002) plane. The crystalline grain of films is about 40nm in size, which is supported by both the Sherrer equation and the SEM result. However, the ZnO film is composed of numerous clustered particulates in the size of 200 to 300nm, and each particulate is the compact aggregation of smaller ZnO crystalline grains. It is speculated that the excellent crystallinity of ZnO films may chiefly originate from the cavatition effect of the ultrasonic rinsing process.
基金Financial supports from the National Natural Science Foundation of China(NSFC-No.51272240,51202225,51402265)International S&T Cooperation Program of China(ISTCP-No.2014DFA50240)
文摘With the wide using of transparent alumina ceramics and synthetic sapphire,the demand of the furnace for them is promoted steadily,and the furnace lining materials are upgrading. Having low thermal conductivity and the same composition with transparent alumina ceramics and sapphire,porous alumina ceramics with high purity are expected to lower the high energy consumption without contamination. In this paper,porous alumina ceramics with porosity of 75. 3%- 81. 9% and impurity less than 0. 1% were prepared by a foaming method combined with gelcasting,using high purity alumina powders as raw materials. By changing the amount of foaming agent and the solid content,the microstructure and properties of porous ceramics were tailored. The compressive strength of the porous ceramics ranged from( 22. 4 ± 2. 5) MPa to( 48. 1 ± 3. 1) MPa,the thermal conductivity of porous ceramics at 1 000 ℃ ranged between 0. 41- 0. 65 W·( m·K)^(-1).
文摘In this work,Yb2O3 and Mg O were used as sintering aids in preparing silicon nitride ceramics by gas pressure sintering( 0. 6 MPa N2atmosphere) to investigate how the amounts of Yb2O3- Mg O influence the mechanical properties and thermal conductivity of silicon nitride ceramics. The total contents of Yb2O3- Mg O added were 1 mol%,2 mol%,4 mol%,6 mol%,8 mol%,10 mol%,12 mol%,14 mol%,keeping the Yb2O3-Mg O molar ratio of 1 ∶ 1 steadily. Curves of the relative density,thermal conductivity and bending strength plotted against the aids content present a ‘mountain'shape with a maximum at nearly 10 mol% aids. The fracture toughness increased with the amounts of additives up to10 mol% and decreased slightly thereafter. The mechanical properties and thermal conductivity were almost proportional to the amount of the additives before10 mol%. When the content of aids exceeded 10 mol%,it would weaken the mechanical properties and thermal conductivity of the ceramics. The optimum content of Yb2O3- Mg O was 10 mol% by gas pressure sintering( 0. 6MPa) at 1 850 ℃ for 4 h,which led to a relative density of 98. 9%,a flexural strength of( 966 ± 38)MPa as well as a fracture toughness of( 6. 29 ± 0. 29)MPa·m1 /2and thermal conductivity of 82 W /( m·K).
基金Supported by the Ministry of Science and Technology and Ministry of Education of China, the Key Project of Chinese Ministry of Education （No 306020）, the National Natural Science Foundation of China under Grant Nos i0734040, 10734140 and 10674021, the National High-Tech ICF Committee in China and the Yin-He Super-Computer Center, Institute of Applied Physics and Mathematics, Beijing, China, and the National Basic Research Programme of China under Graut Nos 2006CB921408 and 2005CB724500.
基金National Key R&D Program of China,Grant/Award Number:2022YFB3807700National Natural Science Foundation of China,Grant/Award Numbers:U20A20248,52372247+4 种基金Key-Area Research and Development Program of Guangdong Province,Grant/Award Number:2020B090919001Shanghai Pujiang Programme,Grant/Award Number:23PJD110China Academy of Engineering Physics,Grant/Award Number:U1930208Natural Science Foundation of Shandong Province,Grant/Award Number:ZR2021QB007Science and Technology Commission of Shanghai Municipality,Grant/Award Number:18DZ2280800。
文摘Solid-state batteries represent the future of energy storage technology,offering improved safety and energy density.Garnet-type Li7La3Zr2O12(LLZO)solidstate electrolytes-based solid-state lithium batteries(SSLBs)stand out for their appealingmaterial properties and chemical stability.Yet,their successful deployment depends on conquering interfacial challenges.This review article primarily focuses on the advancement of interfacial engineering for LLZO-based SSLBs.We commence with a concise introduction to solid-state electrolytes and a discussion of the challenges tied to interfacial properties in LLZO-based SSLBs.We deeply explore the correlations between structure and properties and the design principles vital for achieving an ideal electrode/electrolyte interface.Subsequently,we delve into the latest advancements and strategies dedicated to overcoming these challenges,with designated sections on cathode and anode interface design.In the end,we share our insights into the advancements and opportunities for interface design in realizing the full potential of LLZO-based SSLBs,ultimately contributing to the development of safe and high-performance energy storage solutions.
基金supported by the National Natural Science Foundation of China(Nos.22125903 and 51872283)Dalian Innovation Support Plan for High Level Talents(No.2019RT09)+2 种基金Dalian National Laboratory for Clean Energy(DNL),CAS,DNL Cooperation Fund,CAS(Nos.DNL201912,DNL201915,DNL202016,and DNL202019)DICP(No.DICP I2020032)the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(Nos.YLU‐DNL Fund 2021002 and YLU‐DNL 2021009).
文摘The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathode catalysts with high activity and stability is crucial to overcome the terrible issues at high current density.Herein,we report a surface engineering strategy to adjust the surface electron structure of boron(B)‐doped PtNi nanoalloy on carbon nanotubes(PtNiB@CNTs)as an efficient bifunctional cathodic catalyst for high‐rate and long‐life Li‐O2 batteries.Notably,the Li‐O2 batteries assembled with as‐prepared PtNiB@CNT catalyst exhibit ultrahigh discharge capacity of 20510 mA·h/g and extremely low overpotential of 0.48 V at a high current density of 1000 mA/g,both of which outperform the most reported Pt‐based catalysts recently.Meanwhile,our Li‐O2 batteries offer excellent rate capability and ultra‐long cycling life of up to 210 cycles at 1000 mA/g under a fixed capacity of 1000 mA·h/g,which is two times longer than those of Pt@CNTs and PtNi@CNTs.Furthermore,it is revealed that surface engineering of PtNi nanoalloy via B doping can efficiently tailor the electron structure of nanoalloy and optimize the adsorption of oxygen species,consequently delivering excellent Li‐O2 battery performance.Therefore,this strategy of regulating the nanoalloy by doping nonmetallic elements will pave an avenue for the design of high‐performance catalysts for metal‐oxygen batteries.
基金the National Natural Science Foundation of China(Grant No.U1232111)the Hundred Talent Program of Chinese Academy of Sciences
文摘The garnet-type Li7La3Zr2O12 ceramic is a promising solid electrolyte for all-solid-state secondary lithium batteries. However, it faces the problem of lithium volatilization during sintering, which may cause low density and deterioration of ionic conductivity. In this work, the effects of sintering temperature and addition on the density as well as the lithium ion conductivity of Li7-xLa3Zr2-xTaxO12 (LLZTO, x=0.25) ceramics prepared by solid state reaction have been studied. It is found that optimization of the sintering temperature leads to a minor increase in the ceramic density, yielding an optimum ionic conductivity of 2.9×10-4 S·cm-1 at 25℃. Introduction of Li 3 PO 4 addition in an appropriate concentration can obviously increase the density, leading to an optimum ionic conductivity of 7.2×10-4 S·cm-1 at 25℃. This value is superior to the conductivity data in most recent reports on the LLZTO ceramics.
基金the financial support from the National Key Research and Development Program of China (2016YFB0700204)Natural Science Foundation of Jiangsu Province (No. BK20140472)+2 种基金NSFC (51602332, 51502327)Science and Technology Commission of Shanghai Municipality (15520720400, 15YF1413800, 14DZ2261203, 16DZ2260603)One Hundred Talent Plan of Chinese Academy of Sciences
文摘A series of N-doped carbon materials(NCs)were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile onestep pyrolysis method. The characterization of microstructural features shows that the NCs samples are composed of few-layered graphene-like nanoflakes with controlled in situ N doping, which is attributed to the confined pyrolysis of citric acid within the interlayers of the dicyandiamide-derived g-C_3N_4 with high nitrogen contents. Evidently, the pore volumes of the NCs increased with the increasing content of dicyandiamide in the precursor. Among these samples, the NCs nanoflakes prepared with the citric acid/dicyandiamide mass ratio of 1:6, NC-6,show the highest N content of ~6.2 at%, in which pyridinic and graphitic N groups are predominant. Compared to the commercial Pt/C catalyst, the as-prepared NC-6 exhibits a small negative shift of ~66 mV at the half-wave potential, demonstrating excellent electrocatalytic activity in the oxygen reduction reaction. Moreover, NC-6 also shows better long-term stability and resistance to methanol crossover compared to Pt/C. The efficient and stable performance are attributed to the graphene-like microstructure and high content of pyridinic and graphitic doped nitrogen in the sample, which creates more active sites as well as facilitating charge transfer due to the close four-electron reaction pathway. The superior electrocatalytic activity coupled with the facile synthetic method presents a new pathway to cost-effective electrocatalysts for practical fuel cells or metal–air batteries.
基金the financial support from the National Key R&D Program of China(Grant No.2016YFA0203700)the National Natural Science Foundation of China(Grant Nos.51872185,51722211,51672303,81672131,81672143,82072417 and 81802247)+2 种基金the Program of Shanghai Academic Research Leader(Grant No.18XD1404300)the National Key Research and Development Project of China(Grant No.2018YFC1106303)the Science and Technology Commission of Shanghai Municipality(Grant No.17060502400).
文摘Early surgical resection and chemotherapy of bone cancer are commonly used in the treatment of bone tumor,but it is still highly challenging to prevent recurrence and fill the bone defect caused by the resection site.In this work,we report a rational integration of photonic-responsive two-dimensional(2D)ultrathin niobium carbide(Nb2C)MXene nanosheets(NSs)into the 3D-printed bone-mimetic scaffolds(NBGS)for osteosarcoma treatment.The integrated 2D Nb2C-MXene NSs feature specific photonic response in the second near-infrared(NIR-II)biowindow with high tissue-penetrating depth,making it highly efficient in killing bone cancer cells.Importantly,Nb-based species released by the biodegradation of Nb2C MXene can obviously promote the neogenesis and migration of blood vessels in the defect site,which can transport more oxygen,vitamins and energy around the bone defect for the reparative process,and gather more immune cells around the defect site to accelerate the degradation of NBGS.The degradation of NBGS provides sufficient space for the bone remodeling.Besides,calcium and phosphate released during the degradation of the scaffold can promote the mineralization of new bone tissue.The intrinsic multifunctionality of killing bone tumor cell and promoting angiogenesis and bone regeneration makes the engineered Nb2C MXeneintegrated composite scaffolds a distinctive implanting biomaterial on the efficient treatment of bone tumor.
基金National Key Research and Development Program of China(2017YFB0310400)National Natural Science Foundation of China(51572277,51702340)+1 种基金Shanghai Sailing Program(17YF1428800)Natural Science Foundation of Shanghai(17ZR1434800)。
文摘As for ceramic stereolithography technique,the preparation of suitable resin-based ceramic slurry is of primary importance.In this study,the effects of powder characteristics such as specific surface area,particle size and distribution,particle morphology on the rheological behavior of zirconia resin-based suspensions were investigated intensively.Results show that the specific surface area of the powder is the most important factor affecting slurry viscosity.Choosing low specific surface area and quasi-spherical shaped powder is more likely to obtain low viscosity slurries.In addition,the influence of solid loading on the flow behavior were also studied using Krieger-Dougherty model.Zirconia samples with the relative density of(97.83±0.33)%were obtained after sintering at 1550℃.No obvious abnormal grain growth in the microstructure of the sintered body is observed.Results indicate that after the optimization of the processing parameters with the help of rheology characterization,complex-shaped high-quality zirconia parts can be obtained using the stereolithography technique.
文摘Eu^2＋-doped Ba3Si6012N2 green phosphors were prepared by microwave assisted sintering method at 1275℃ for 4 h, while the counterparts using conventional solid-state reaction method were synthesized at temperature higher than 1300℃ and for to 10 h. Microwave assisted sintering could reduce the activation energy and enhance the diffu- sion rate, thus greatly improved the sintering. Moreover, the influence of Si3N4 content on phase formation, morphol- ogy, absorption, and quantum efficiency, and photoluminescence properties of phosphors were studied. As a result, the Ba3Si6OI2N2：Eu^2＋ samples sintered by microwave assisted sintering method have a higher phase purity and photo- luminescence intensity under ultraviolet excitation as compared with samples sintered in the conventional tube furnace The proposed method is a potential preparation method for the oxynitride phosphors with strong photoluminescence and high phase purity.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10979069)the "Hundred Talent Program" of Chinese Academy of Sciences
文摘As essential electrochromic(EC) materials are related to energy savings in fenestration technology,tungsten oxide(WO3) films have been intensively studied recently.In order to achieve better understanding of the mechanism of EC properties,and thus facilitate optimization of device performance,clarification of the correlation between cation storage and transfer properties and the coloration performance is needed.In this study,transparent polycrystalline and amorphous WO3 thin films were deposited on SnO2:F-coated glass substrates by the pulsed laser deposition technique.Investigation into optical transmittance in a wavelength range of 400-800 nm measured at a current density of 130 μA·cm-2 with the applied potential ranging from 3.2 to 2.2 V indicates that polycrystalline films have a larger optical modulation of ～ 30% at 600 nm and a larger coloration switch time of 95 s in the whole wavelength range compared with amorphous films(～ 24% and 50 s).Meanwhile,under the same conditions,polycrystalline films show a larger lithium storage capacity corresponding to a Li/W ratio of 0.5,a smaller lithium diffusion coefficient(2×10-12cm2·s-1 for Li/W=0.24) compared with the amorphous ones,which have a Li/W ratio of 0.29 and a coefficient of ～2.5×10-11cm2·s-1 as Li/W=0.24.These results demonstrate that the large optical modulation relates to the large lithium storage capacity,and the fast coloration transition is associated with fast lithium diffusion.
文摘The title new compounds with chemical formula RE CuBi2 were synthesized by arc melting method followed by annealing. The crystal structures refined using Rietveld method and X-ray powder diffraction data show to be isotypic to CaMnBi2 structure type with space group P4/nmm（No.129）. The unit cell parameters are a=（0.457946（4）nm）,c=0.98858（2）nm, V=0.207319（8）nm3 for LaCuBi2, a=0.449279（9）nm, c= 0.95958（4）nm, V= 0.19369（2）nm3 for GdCuBi2 and a=0.447680（7）nm, c=0.95124（3）nm,V=0.190644（5）nm3 for DyCuBi2 respectively, showing lanthanide contraction. The structure is characterized by layers of edge-shearing CuBi4 tetrahedron and covalently bonded Bi square net separated by rare earth atoms.
基金Supported by the National High-Tech Research and Development Program of China under Grant Nos 2008AA03Z410 and 2006AA03Z107, the National Natural Science Foundation of China under Grant Nos 60837003, 50777065 and 50602047, the Innovation Funds from Shanghai Institute of Ceramics of Chinese Academy of Sciences under Grant No SCX0608, and the Fund of National Engineering Research Center for Optoelectronic Crystalline Materials （2005DC105003） under Grant No 2007K05.
