A new one-dimensional aluminum fluorophosphate, AlP2O5（OH）3F·0.5[H2dien] （dien=diethylenetriamine）, was solvothermally synthesized by using organic amine as the structure directing agent, and its structure wa...A new one-dimensional aluminum fluorophosphate, AlP2O5（OH）3F·0.5[H2dien] （dien=diethylenetriamine）, was solvothermally synthesized by using organic amine as the structure directing agent, and its structure was determined by single-crystal X-ray diffraction. The complex inorganic architecture consists of trans-corner-sharing AlO4F2 octahedra chain decorated by phosphate tetrahedra along both sides of the -F-Al-F-Al-F- backbone displaying a series of Al2P three-membered rings, which will represent a new fundamental structural type in metal phosphates. The results of CHN elemental analysis, EDS, and TGA are also presented. Crystal data： C4H18Al2F2N3O16P4, monoclinic, space group P21/c with a=6.9107（14）, b=15.749（3）, c=8.9741（18） , β=109.829（2）o, V=918.8（3） 3, Z=2, Mr=580.05, Dc=2.097 g/cm3, μ=0.618 mm-1, S=1.022, F（000）=590, the final R=0.0510 and wR=0.1284 for 1607 observed reflections （I 〉 2σ（I））.展开更多
Using the technique of high-temperature melting, a new Er3＋/Yb3＋ co-doped fluorophosphate glass was prepared. The absorption and fluorescence spectra were investigated in depth. The effect of Er3＋ and Yb3＋ concent...Using the technique of high-temperature melting, a new Er3＋/Yb3＋ co-doped fluorophosphate glass was prepared. The absorption and fluorescence spectra were investigated in depth. The effect of Er3＋ and Yb3＋ concentration on the spectroscopic properties of the glass sample was also discussed. According to the Judd Ofelt theory, the oscillator strength was computed. The lifetime of 4113/2 level （t-m） of Er3＋ ions was 8.23 ms, and the full width at half maximum of the dominating emission peak was 68 nm at 1.53 μm. The large stimulated emission cross section of the Er3＋ was calculated by the McCumher theory. The spectroscopic properties of Er3＋ ion were compared with those in different glasses. The full width at half maximum and σe are larger than those of other glass hosts, indicating this studied glass may be a potentially useful candidate for high-gain erbium-doped fiber amplifier.展开更多
Poly(ethylene terephthalate)(PET)/tin fluorophosphate glass(Pglass) hybrids were prepared via melt blending in the present paper,and the phase morphology,dynamic rheology,crystallization behavior,dynamic and static me...Poly(ethylene terephthalate)(PET)/tin fluorophosphate glass(Pglass) hybrids were prepared via melt blending in the present paper,and the phase morphology,dynamic rheology,crystallization behavior,dynamic and static mechanical properties,and thermal stability of the hybrids have been investigated.Scanning electron microscopy(SEM) and transmission electron microscopy(TEM) showed the Pglass particles well dispersed in the PET matrix within a nanoscale.The results showed that the addition of Pglass induced some advantages on the properties of PET matrix,such as the decreasing of melt viscosity,increasing the isothermal crystallization rate and crystallinity,and improving the storage modulus and elasticity modulus.展开更多
The rapid diffusion of renewable energy boosts the wide deployment of large-scale energy storage system.With the low cost and high crustal abundance,sodium-ion battery(SIB)technology is expected to become a dominant t...The rapid diffusion of renewable energy boosts the wide deployment of large-scale energy storage system.With the low cost and high crustal abundance,sodium-ion battery(SIB)technology is expected to become a dominant technology in that area in the future.Toward the practical application,novel cathode materials are urged to develop that show high energy density without sacrificing their cost and benignity to the environment.While the years of many studies,this still remains a huge challenge to battery scientists.In this review,we discuss recent breakthroughs in SIB cathode materials with high energy density,namely fluorphosphates and fluorosulfates.The design of materials,the crystal structure,the electrochemical performance,and the underlaying intercalation mechanism are systematically reviewed.Useful strategies and research directions are also provided to advance future high-energy,low-cost,and ecofriendly cathode materials for next generation SIB.展开更多
In the field of materials science and engineering,controlling over shape and crystal orientation remains a tremendous challenge.Herein,we realize a nano self-assembly morphology adjustment of Na3V2(PO4)2F3(NVPF)materi...In the field of materials science and engineering,controlling over shape and crystal orientation remains a tremendous challenge.Herein,we realize a nano self-assembly morphology adjustment of Na3V2(PO4)2F3(NVPF)material,based on surface energy evolution by partially replacing V3+with aliovalent Mn2+.Crystal growth direction and surface energy evolution,main factors in inducing the nano self-assembly of NVPF with different shapes and sizes,are revealed by high-resolution transmission electron microscope combined with density functional theory.Furthermore,NVPF with a two-dimensional nanosheet structure(NVPF-NS)exhibits the best rate capability with 68 mAh·g−1 of specific capacity at an ultrahigh rate of 20 C and cycle stability with 80.7%of capacity retention over 1,000 cycles at 1 C.More significantly,when matched with Se@reduced graphene oxide(rGO)anode,NVPF-NS//Se@rGO sodium-ion full cells display a remarkable long-term stability with a high capacity retention of 93.8%after 500 cycles at 0.5 C and−25°C.Consequently,experimental and theoretical calculation results manifest that NVPF-NS demonstrates such superior performances,which can be mainly due to its inherent crystal structure and preferential orientation growth of{001}facets.This work will promise insights into developing novel architectural design strategies for high-performance cathode materials in advanced sodium-ion batteries.展开更多
In this study,novel yellow-emitting fluorophosphate NaCa_(3)Bi(PO_(4))_(3)F phosphors doped with different concentrations of Dy^(3+)ions were first obtained via high-temperature solid-state reaction.The crystal struct...In this study,novel yellow-emitting fluorophosphate NaCa_(3)Bi(PO_(4))_(3)F phosphors doped with different concentrations of Dy^(3+)ions were first obtained via high-temperature solid-state reaction.The crystal structure,phase purity,particle morphology,photoluminescence(PL)properties,thermal stability,and luminescence decay curves of the resulting phosphors were then characterized in detail.Under the excitation of 349 nm,the three dominant peaks of the NaCa_(3)Bi(PO_(4))_(3)F:Dy^(3+)are centered at 480 nm(^(4)F_(9/2)-^(6)H_(15/2)),577 nm(^(4)F_(9/2)-^(6)H_(13/2)),and 662 nm(^(4)F_(9/2)-^(6)H_(11/2)).The optimal doping concentration of Dy^(3+)ions in the NaCa_(3)Bi(PO_(4))_(3)F:xDy^(3+)phosphors is x=5 mol%.The phosphors show excellent thermal stability with high activation energy(Ea=0.32 eV).Eventually,the synthesized white lightemitting diode(w-LED)demonstrates the Commission International de L’Eclairage(CIE)chromaticity coordinates of(0.341,0.334),a good correlated color temperature(CCT)of 5083 K,and a high color rendering index(Ra)of 92.Revealing its potential as yellow-emitting phosphors,the feasibility of the fabricated apatite-type NaCa_(3)Bi(PO_(4))_(3)F:Dy^(3+)fluorophosphate phosphors was confirmed for wLEDs.展开更多
Na_(3)V_(2)(PO_(4))_(2)O_(2)F(NVPOF)has received considerable interest as a promising cathode material for sodium-ion batteries because of its high working voltage and good structural/thermal stability.However,the slu...Na_(3)V_(2)(PO_(4))_(2)O_(2)F(NVPOF)has received considerable interest as a promising cathode material for sodium-ion batteries because of its high working voltage and good structural/thermal stability.However,the sluggish electrode reaction resulting from its low intrinsic electronic conductivity significantly restricts its electrochemical performance and thus its practical application.Herein,Nb-doped Na_(3)V_(2-x)Nb_(x)(PO_(4))_(2)O_(2)F/graphene(rGO)composites(x=0,0.05,0.1)were prepared using a solvothermal method followed by calcination.Compared to the un-doped NVPOF/r GO,doping V-site with high-valence Nb element(Nb^(5+))(Na_(3)V_(1.95)Nb_(0.05)(PO_(4))_(2)O_(2)F/r GO(NVN05POF/rGO))can result in the generated V4^(+)/V3^(+)mixed-valence,ensuring the lower bandgap and thus the increased intrinsic electronic conductivity.Besides,the expanded lattice space favors the Na^(+)migration.With the structure feature where NVN05POF particles are attached to the rGO sheets,the electrode reaction kinetics is further accelerated owing to the well-constructed electron conductive network.As a consequence,the as-prepared NVN05POF/r GO sample exhibits a high specific capacity of~72 m Ah·g^(-1)at 10C(capacity retention of 65.2%(vs.0.5C))and excellent long-term cycling stability with the capacity fading rate of~0.099%per cycle in 500 cycles at 5C.展开更多
This work presents a brief introduction on three kinds of newly developed Nd^(3+)-doped laser glasses in Shanghai Institute of Optics and Fine Mechanics(SIOM), China. Two Nd^(3+)-doped phosphate glasses with lower the...This work presents a brief introduction on three kinds of newly developed Nd^(3+)-doped laser glasses in Shanghai Institute of Optics and Fine Mechanics(SIOM), China. Two Nd^(3+)-doped phosphate glasses with lower thermal expansion coefficient and thermal shock resistance 4 times higher than that of N31 glass are developed for laser processing.Nd:Silicate and Nd:Aluminate glasses with peak emission wavelength at 1061 and 1065 nm, effective emission bandwidth of 34 and 50 nm, respectively, are developed for Exawatt-class laser system application. Fluorophosphate glasses with low nonlinear refractive index(n_2=0.6–0.86) and long fluorescence lifetime(430–510 μs) are investigated for the purpose of decreasing B integral in high-power laser system. The properties of all these glasses are presented and compared with those of commercial neodymium laser glasses.展开更多
本论文采用快速微波辅助低温回流策略制备了桑椹形Na_3V_2(PO_4)_2O_2F@C纳米复合材料.研究表明微乳液中的V(acac)_3反胶束体系对该自组装结构的形成起到了关键作用.制得的Na_3V_2(PO_4)_2O_2F晶粒沿着[002]方向生长并被原位包封在碳壳...本论文采用快速微波辅助低温回流策略制备了桑椹形Na_3V_2(PO_4)_2O_2F@C纳米复合材料.研究表明微乳液中的V(acac)_3反胶束体系对该自组装结构的形成起到了关键作用.制得的Na_3V_2(PO_4)_2O_2F晶粒沿着[002]方向生长并被原位包封在碳壳中,形成了高度稳定的自组装结构,这不仅有利于Na^+/e^-的快速迁移,而且能够有效改善电极材料的循环性能并抑制电压衰减.作为钠离子电池正极材料,在0.1 C条件下, Na_3V_2(PO_4)_2O_2F@C的初始放电容量约为127.9 mA h g^(-1).在高倍率(20 C)条件下,容量达88.1 mA h g^(-1), 2000次循环后容量保持率为82.1%.此外,利用非原位X射线衍射, X射线光电子能谱和恒电流间歇滴定技术,初步研究了Na_3V_2(PO4)_2O_2F@C在充放电过程中的反应机理和Na^+迁移机制.同时,在Li/Na离子混合电池当中, Na_3V_2(PO_4)_2O_2F@C也表现出了优异的倍率和循环性能.上述微波辅助低温回流合成策略为开发高性能电化学储能材料开辟了新的途径.展开更多
In this study,a pseudo-layered Na super-ionic conductor of Na3V2(PO4)2F3 (NVPF)/C cathode for sodium-ion batteries is prepared successfully using a facile polyol refluxing process without any impurity phases.The X-ray...In this study,a pseudo-layered Na super-ionic conductor of Na3V2(PO4)2F3 (NVPF)/C cathode for sodium-ion batteries is prepared successfully using a facile polyol refluxing process without any impurity phases.The X-ray diffraction and Rietveld refinement results confirm that NVPF possesses tetragonal NASICON-type lattice with a space group of P42/mnm.In this preparative method,polyol is utilized as a solvent as well as a carbon source.The presence of nanosized NVPF particles in the carbon network is confirmed by field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM).The existence of carbon is analyzed by Raman scattering and elemental analysis.When applied as a Na-storage material in a potential window of 2.0-4.3 V,the electrode exhibits two flat voltage plateaus at 3.7 and 4.2 V with an electrochemically active V^3+/V^4+ redox couple.In addition,Na3V2(PO4)2F3/C composite achieved a retention capacity of ~ 88% even after 1,500 cycles at 15 C.Moreover,at high current densities of 30 and 50 C,Na3V2(PO4)2F3/C cathode retains the specific discharge capacities of 108.4 and 105.9 mAh·g-1,respectively,revealing the structural stability of the material prepared through a facile polyol refluxing method.展开更多
1 Results Although phospho-olivine LiFePO4 has attracted much attention as next-generation cathode, the gravimetric energy density is restricted. Fluorophosphate Li2CoPO4F is strong candidate for new high-voltage cath...1 Results Although phospho-olivine LiFePO4 has attracted much attention as next-generation cathode, the gravimetric energy density is restricted. Fluorophosphate Li2CoPO4F is strong candidate for new high-voltage cathode with large capacity,if 2 Li+ can be reversibly removed[1]. In the present study, we tried to synthesized Li2CoPO4F by two methods, solid state reaction in vacuumed quartz tube with Pt crucible and melt-quench process using Cu single roller in Ar. The obtained latter amorphous sample was...展开更多
基金supported by the National Natural Science Foundation of China (Nos. 20971064 and 21071074)the Foundation of Education Committee of Henan Province (No. 092102210315)
文摘A new one-dimensional aluminum fluorophosphate, AlP2O5（OH）3F·0.5[H2dien] （dien=diethylenetriamine）, was solvothermally synthesized by using organic amine as the structure directing agent, and its structure was determined by single-crystal X-ray diffraction. The complex inorganic architecture consists of trans-corner-sharing AlO4F2 octahedra chain decorated by phosphate tetrahedra along both sides of the -F-Al-F-Al-F- backbone displaying a series of Al2P three-membered rings, which will represent a new fundamental structural type in metal phosphates. The results of CHN elemental analysis, EDS, and TGA are also presented. Crystal data： C4H18Al2F2N3O16P4, monoclinic, space group P21/c with a=6.9107（14）, b=15.749（3）, c=8.9741（18） , β=109.829（2）o, V=918.8（3） 3, Z=2, Mr=580.05, Dc=2.097 g/cm3, μ=0.618 mm-1, S=1.022, F（000）=590, the final R=0.0510 and wR=0.1284 for 1607 observed reflections （I 〉 2σ（I））.
基金supported by the National Natural Science Foundation of China (Grant No. 11075026)
文摘Using the technique of high-temperature melting, a new Er3＋/Yb3＋ co-doped fluorophosphate glass was prepared. The absorption and fluorescence spectra were investigated in depth. The effect of Er3＋ and Yb3＋ concentration on the spectroscopic properties of the glass sample was also discussed. According to the Judd Ofelt theory, the oscillator strength was computed. The lifetime of 4113/2 level （t-m） of Er3＋ ions was 8.23 ms, and the full width at half maximum of the dominating emission peak was 68 nm at 1.53 μm. The large stimulated emission cross section of the Er3＋ was calculated by the McCumher theory. The spectroscopic properties of Er3＋ ion were compared with those in different glasses. The full width at half maximum and σe are larger than those of other glass hosts, indicating this studied glass may be a potentially useful candidate for high-gain erbium-doped fiber amplifier.
文摘Poly(ethylene terephthalate)(PET)/tin fluorophosphate glass(Pglass) hybrids were prepared via melt blending in the present paper,and the phase morphology,dynamic rheology,crystallization behavior,dynamic and static mechanical properties,and thermal stability of the hybrids have been investigated.Scanning electron microscopy(SEM) and transmission electron microscopy(TEM) showed the Pglass particles well dispersed in the PET matrix within a nanoscale.The results showed that the addition of Pglass induced some advantages on the properties of PET matrix,such as the decreasing of melt viscosity,increasing the isothermal crystallization rate and crystallinity,and improving the storage modulus and elasticity modulus.
基金supported by the National Natural Science Foundation of China(No.22179098).
文摘The rapid diffusion of renewable energy boosts the wide deployment of large-scale energy storage system.With the low cost and high crustal abundance,sodium-ion battery(SIB)technology is expected to become a dominant technology in that area in the future.Toward the practical application,novel cathode materials are urged to develop that show high energy density without sacrificing their cost and benignity to the environment.While the years of many studies,this still remains a huge challenge to battery scientists.In this review,we discuss recent breakthroughs in SIB cathode materials with high energy density,namely fluorphosphates and fluorosulfates.The design of materials,the crystal structure,the electrochemical performance,and the underlaying intercalation mechanism are systematically reviewed.Useful strategies and research directions are also provided to advance future high-energy,low-cost,and ecofriendly cathode materials for next generation SIB.
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China(Nos.91963118,52173246,and 52102213)the Science Technology Program of Jilin Province(No.20200201066JC)the 111 Project(No.B13013).
文摘In the field of materials science and engineering,controlling over shape and crystal orientation remains a tremendous challenge.Herein,we realize a nano self-assembly morphology adjustment of Na3V2(PO4)2F3(NVPF)material,based on surface energy evolution by partially replacing V3+with aliovalent Mn2+.Crystal growth direction and surface energy evolution,main factors in inducing the nano self-assembly of NVPF with different shapes and sizes,are revealed by high-resolution transmission electron microscope combined with density functional theory.Furthermore,NVPF with a two-dimensional nanosheet structure(NVPF-NS)exhibits the best rate capability with 68 mAh·g−1 of specific capacity at an ultrahigh rate of 20 C and cycle stability with 80.7%of capacity retention over 1,000 cycles at 1 C.More significantly,when matched with Se@reduced graphene oxide(rGO)anode,NVPF-NS//Se@rGO sodium-ion full cells display a remarkable long-term stability with a high capacity retention of 93.8%after 500 cycles at 0.5 C and−25°C.Consequently,experimental and theoretical calculation results manifest that NVPF-NS demonstrates such superior performances,which can be mainly due to its inherent crystal structure and preferential orientation growth of{001}facets.This work will promise insights into developing novel architectural design strategies for high-performance cathode materials in advanced sodium-ion batteries.
基金Project supported by Chinese Universities Scientific Fund(2452019076,2452020017)。
文摘In this study,novel yellow-emitting fluorophosphate NaCa_(3)Bi(PO_(4))_(3)F phosphors doped with different concentrations of Dy^(3+)ions were first obtained via high-temperature solid-state reaction.The crystal structure,phase purity,particle morphology,photoluminescence(PL)properties,thermal stability,and luminescence decay curves of the resulting phosphors were then characterized in detail.Under the excitation of 349 nm,the three dominant peaks of the NaCa_(3)Bi(PO_(4))_(3)F:Dy^(3+)are centered at 480 nm(^(4)F_(9/2)-^(6)H_(15/2)),577 nm(^(4)F_(9/2)-^(6)H_(13/2)),and 662 nm(^(4)F_(9/2)-^(6)H_(11/2)).The optimal doping concentration of Dy^(3+)ions in the NaCa_(3)Bi(PO_(4))_(3)F:xDy^(3+)phosphors is x=5 mol%.The phosphors show excellent thermal stability with high activation energy(Ea=0.32 eV).Eventually,the synthesized white lightemitting diode(w-LED)demonstrates the Commission International de L’Eclairage(CIE)chromaticity coordinates of(0.341,0.334),a good correlated color temperature(CCT)of 5083 K,and a high color rendering index(Ra)of 92.Revealing its potential as yellow-emitting phosphors,the feasibility of the fabricated apatite-type NaCa_(3)Bi(PO_(4))_(3)F:Dy^(3+)fluorophosphate phosphors was confirmed for wLEDs.
基金supported by the Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities) (No.FRFIDRY-21-023)the Beijing Natural Science Foundation (Nos.2194079 and 2222062)the National Natural Science Foundation of China (Nos.52074023 and 52102205)。
文摘Na_(3)V_(2)(PO_(4))_(2)O_(2)F(NVPOF)has received considerable interest as a promising cathode material for sodium-ion batteries because of its high working voltage and good structural/thermal stability.However,the sluggish electrode reaction resulting from its low intrinsic electronic conductivity significantly restricts its electrochemical performance and thus its practical application.Herein,Nb-doped Na_(3)V_(2-x)Nb_(x)(PO_(4))_(2)O_(2)F/graphene(rGO)composites(x=0,0.05,0.1)were prepared using a solvothermal method followed by calcination.Compared to the un-doped NVPOF/r GO,doping V-site with high-valence Nb element(Nb^(5+))(Na_(3)V_(1.95)Nb_(0.05)(PO_(4))_(2)O_(2)F/r GO(NVN05POF/rGO))can result in the generated V4^(+)/V3^(+)mixed-valence,ensuring the lower bandgap and thus the increased intrinsic electronic conductivity.Besides,the expanded lattice space favors the Na^(+)migration.With the structure feature where NVN05POF particles are attached to the rGO sheets,the electrode reaction kinetics is further accelerated owing to the well-constructed electron conductive network.As a consequence,the as-prepared NVN05POF/r GO sample exhibits a high specific capacity of~72 m Ah·g^(-1)at 10C(capacity retention of 65.2%(vs.0.5C))and excellent long-term cycling stability with the capacity fading rate of~0.099%per cycle in 500 cycles at 5C.
文摘This work presents a brief introduction on three kinds of newly developed Nd^(3+)-doped laser glasses in Shanghai Institute of Optics and Fine Mechanics(SIOM), China. Two Nd^(3+)-doped phosphate glasses with lower thermal expansion coefficient and thermal shock resistance 4 times higher than that of N31 glass are developed for laser processing.Nd:Silicate and Nd:Aluminate glasses with peak emission wavelength at 1061 and 1065 nm, effective emission bandwidth of 34 and 50 nm, respectively, are developed for Exawatt-class laser system application. Fluorophosphate glasses with low nonlinear refractive index(n_2=0.6–0.86) and long fluorescence lifetime(430–510 μs) are investigated for the purpose of decreasing B integral in high-power laser system. The properties of all these glasses are presented and compared with those of commercial neodymium laser glasses.
基金supported by the National Natural Science Foundation of China (21303042, 21875097, 21671096 and 21603094)Guangdong Special Support for the Science and Technology Leading Young Scientist (2016TQ03C919)the Basic Research Project of the Science and Technology Innovation Commission of Shenzhen (JCYJ20170412153139454 and JCYJ20170817110251498)
文摘本论文采用快速微波辅助低温回流策略制备了桑椹形Na_3V_2(PO_4)_2O_2F@C纳米复合材料.研究表明微乳液中的V(acac)_3反胶束体系对该自组装结构的形成起到了关键作用.制得的Na_3V_2(PO_4)_2O_2F晶粒沿着[002]方向生长并被原位包封在碳壳中,形成了高度稳定的自组装结构,这不仅有利于Na^+/e^-的快速迁移,而且能够有效改善电极材料的循环性能并抑制电压衰减.作为钠离子电池正极材料,在0.1 C条件下, Na_3V_2(PO_4)_2O_2F@C的初始放电容量约为127.9 mA h g^(-1).在高倍率(20 C)条件下,容量达88.1 mA h g^(-1), 2000次循环后容量保持率为82.1%.此外,利用非原位X射线衍射, X射线光电子能谱和恒电流间歇滴定技术,初步研究了Na_3V_2(PO4)_2O_2F@C在充放电过程中的反应机理和Na^+迁移机制.同时,在Li/Na离子混合电池当中, Na_3V_2(PO_4)_2O_2F@C也表现出了优异的倍率和循环性能.上述微波辅助低温回流合成策略为开发高性能电化学储能材料开辟了新的途径.
文摘In this study,a pseudo-layered Na super-ionic conductor of Na3V2(PO4)2F3 (NVPF)/C cathode for sodium-ion batteries is prepared successfully using a facile polyol refluxing process without any impurity phases.The X-ray diffraction and Rietveld refinement results confirm that NVPF possesses tetragonal NASICON-type lattice with a space group of P42/mnm.In this preparative method,polyol is utilized as a solvent as well as a carbon source.The presence of nanosized NVPF particles in the carbon network is confirmed by field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM).The existence of carbon is analyzed by Raman scattering and elemental analysis.When applied as a Na-storage material in a potential window of 2.0-4.3 V,the electrode exhibits two flat voltage plateaus at 3.7 and 4.2 V with an electrochemically active V^3+/V^4+ redox couple.In addition,Na3V2(PO4)2F3/C composite achieved a retention capacity of ~ 88% even after 1,500 cycles at 15 C.Moreover,at high current densities of 30 and 50 C,Na3V2(PO4)2F3/C cathode retains the specific discharge capacities of 108.4 and 105.9 mAh·g-1,respectively,revealing the structural stability of the material prepared through a facile polyol refluxing method.
基金supported by the National Key Research and Development Program of China(2016YFA0202603 and 2016YFA0202601)the National Natural Science Fund for Distinguished Young Scholars(51425204)+1 种基金the National Natural Science Foundation of China(51832004,51602239 and 51672307)the International Science&Technology Cooperation Program of China(2013DFA50840)。
文摘1 Results Although phospho-olivine LiFePO4 has attracted much attention as next-generation cathode, the gravimetric energy density is restricted. Fluorophosphate Li2CoPO4F is strong candidate for new high-voltage cathode with large capacity,if 2 Li+ can be reversibly removed[1]. In the present study, we tried to synthesized Li2CoPO4F by two methods, solid state reaction in vacuumed quartz tube with Pt crucible and melt-quench process using Cu single roller in Ar. The obtained latter amorphous sample was...
