Na_(3)V_(2)(PO_(4))_(3)(NVP)cathode material of the sodium ion battery(1 C=117 mAh g-1)has a NASICON-type structure,which not only facilitates the rapid migration of sodium ions,but also has a small volume deformation...Na_(3)V_(2)(PO_(4))_(3)(NVP)cathode material of the sodium ion battery(1 C=117 mAh g-1)has a NASICON-type structure,which not only facilitates the rapid migration of sodium ions,but also has a small volume deformation during sodium ion de-intercalation and the main frame mechanism remains unchanged,and thus is seen as an energy storage material for a wide range of applications,but has a limited electronic conductivity due to its structure.In this paper,NVP cathode materials with finer primary particles are successfully prepared using a simple hydrothermal treatment-assisted sol-gel method.The increased pore size of the NVP materials prepared under the hydrothermal process allows for more active sites and more effective resistance to the volume deformation of sodium ions during insertion/extraction processes,effectively facilitating the diffusion of ions and electrons.The Na_(3)V_(2)(PO_(4))_(3) material obtained by the optimized process exhibited good crystallinity in XRD characterization,as well as superior electrochemical properties in a series of electrochemical tests.A specific capacitance of 106.3 mAh g^(-1) at 0.2 C is demonstrated,compared to 96.5 mAh g^(-1) for Na_(3)V_(2)(PO_(4))_(3) without hydrothermal treatment,and cycling performance is also improved with 93%capacity retention.The calculated sodium ion diffusion coefficient(DNa=5.68×10^(-14))obtained after EIS curve fitting of the improved sample illustrates that the pore structure is beneficial to the performance of the Na_(3)V_(2)(PO_(4))_(3)cathode material.展开更多
通过简单的溶胶-凝胶辅助静电纺丝法得到(113)晶面优势导向的Na_3V_2(PO_4)_3/C钠离子电池正极材料,并通过对比最佳纺丝条件下分别用聚乙烯吡咯烷酮(PVP)和聚氧化乙烯(PEO)作为晶面导向剂制备的两种Na_3V_2(PO_4)_3电极材料的电化学性能...通过简单的溶胶-凝胶辅助静电纺丝法得到(113)晶面优势导向的Na_3V_2(PO_4)_3/C钠离子电池正极材料,并通过对比最佳纺丝条件下分别用聚乙烯吡咯烷酮(PVP)和聚氧化乙烯(PEO)作为晶面导向剂制备的两种Na_3V_2(PO_4)_3电极材料的电化学性能,证明静电纺丝有利于实现Na_3V_2(PO_4)_3(113)晶面择优取向。在相同的电流密度(0.1 C)下,NVP-PVP和NVP-PEO的首周放电比容量分别为112.5 m A·h/g和96.3 m A·h/g,电池循环50周后,NVP-PVP仍然有98.1 m A·h/g的可逆容量保持,NVP-PEO仅仅只剩下34 m A·h/g的可逆容量保持,而即使循环100周后,NVP-PVP的可逆容量仍然在88.2 m A·h/g。结果表明,PVP静电纺丝有利于构建特定的纳米纤维结构和均一的导电碳网络骨架,进而提升主体材料Na_3V_2(PO_4)_3的电化学性能。展开更多
Sodium-ion batteries （SIBs） have attracted increasing attention in the past decades, because of high over-all abundance of precursors, their even geographical distribution, and low cost. Na3V2（PO4）3 （NVP）, atypi...Sodium-ion batteries （SIBs） have attracted increasing attention in the past decades, because of high over-all abundance of precursors, their even geographical distribution, and low cost. Na3V2（PO4）3 （NVP）, atypical sodium super ion conductor （NASlCON）-based electrode material, exhibits pronounced structuralstability, exceptionally high ion conductivity, rendering it a most promising electrode for sodium storage.However. the comparatively low electronic conductivity makes the theoretical capacity of NVP cannot befully accessible even at comparatively low rates, presenting a major drawback for further practical ap-plications, especially when high rate capability is especially important. Thus, many endeavors have beenconformed to increase the surface and intrinsic electrical conductivity of NVP by coating the active mate-rials with a conductive carbon layer, downsizing the NVP particles, combining the NVP particle with vari-ous carbon materials and ion doping strategy. In this review, to get a better understanding on the sodiumstorage in NVP, we firstly present 4 distinct crystal structures in the temperature range of-30℃-225℃ namely α-NVP, β-NVP, β′-NVP and γ-NVP. Moreover, we give an overview of recent approaches to en-hance the surface electrical conductivity and intrinsic electrical conductivity of NVP. Finally, some poten-tial applications of NVP such as in all-climate environment and PHEV, EV fields have been prospected.展开更多
NASICON (Na-super-ionic-conductors)-structured materials have attracted extensive research interest due to their great application potential in secondary batteries. However, the mechanism of capacity fading for NASICO...NASICON (Na-super-ionic-conductors)-structured materials have attracted extensive research interest due to their great application potential in secondary batteries. However, the mechanism of capacity fading for NASICON-structured electrode materials has been rarely studied. In this paper, we synthesized the NASICON-structured Na3V2(PO4)3/C composite by simple sol-gel and high-temperature solid-phase method and investigated its electrochemical performance in Na-Zn hybrid aqueous rechargeable batteries. After characterizing the structure, morphology and composition variations as well as the interfacial resistance changes of Na3V2(PO4)3/C cathode during cycling, we propose a mechanical and interfacial degradation mechanism for capacity fading of NASICON-structured Na3V2(PO4)3/C in Na-Zn hybrid aqueous rechargeable batteries. This work will shed light on enhancing the mechanical and in terfacial stability of NASICON-structured Na3V2(PO4)3/C in Na-Zn hybrid aqueous rechargeable batteries.展开更多
文摘Na_(3)V_(2)(PO_(4))_(3)(NVP)cathode material of the sodium ion battery(1 C=117 mAh g-1)has a NASICON-type structure,which not only facilitates the rapid migration of sodium ions,but also has a small volume deformation during sodium ion de-intercalation and the main frame mechanism remains unchanged,and thus is seen as an energy storage material for a wide range of applications,but has a limited electronic conductivity due to its structure.In this paper,NVP cathode materials with finer primary particles are successfully prepared using a simple hydrothermal treatment-assisted sol-gel method.The increased pore size of the NVP materials prepared under the hydrothermal process allows for more active sites and more effective resistance to the volume deformation of sodium ions during insertion/extraction processes,effectively facilitating the diffusion of ions and electrons.The Na_(3)V_(2)(PO_(4))_(3) material obtained by the optimized process exhibited good crystallinity in XRD characterization,as well as superior electrochemical properties in a series of electrochemical tests.A specific capacitance of 106.3 mAh g^(-1) at 0.2 C is demonstrated,compared to 96.5 mAh g^(-1) for Na_(3)V_(2)(PO_(4))_(3) without hydrothermal treatment,and cycling performance is also improved with 93%capacity retention.The calculated sodium ion diffusion coefficient(DNa=5.68×10^(-14))obtained after EIS curve fitting of the improved sample illustrates that the pore structure is beneficial to the performance of the Na_(3)V_(2)(PO_(4))_(3)cathode material.
文摘通过简单的溶胶-凝胶辅助静电纺丝法得到(113)晶面优势导向的Na_3V_2(PO_4)_3/C钠离子电池正极材料,并通过对比最佳纺丝条件下分别用聚乙烯吡咯烷酮(PVP)和聚氧化乙烯(PEO)作为晶面导向剂制备的两种Na_3V_2(PO_4)_3电极材料的电化学性能,证明静电纺丝有利于实现Na_3V_2(PO_4)_3(113)晶面择优取向。在相同的电流密度(0.1 C)下,NVP-PVP和NVP-PEO的首周放电比容量分别为112.5 m A·h/g和96.3 m A·h/g,电池循环50周后,NVP-PVP仍然有98.1 m A·h/g的可逆容量保持,NVP-PEO仅仅只剩下34 m A·h/g的可逆容量保持,而即使循环100周后,NVP-PVP的可逆容量仍然在88.2 m A·h/g。结果表明,PVP静电纺丝有利于构建特定的纳米纤维结构和均一的导电碳网络骨架,进而提升主体材料Na_3V_2(PO_4)_3的电化学性能。
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
基金financial support from the National Natural Science Foundation of China (No.21501171,51403209,21406221,51177156/E0712)
文摘Sodium-ion batteries （SIBs） have attracted increasing attention in the past decades, because of high over-all abundance of precursors, their even geographical distribution, and low cost. Na3V2（PO4）3 （NVP）, atypical sodium super ion conductor （NASlCON）-based electrode material, exhibits pronounced structuralstability, exceptionally high ion conductivity, rendering it a most promising electrode for sodium storage.However. the comparatively low electronic conductivity makes the theoretical capacity of NVP cannot befully accessible even at comparatively low rates, presenting a major drawback for further practical ap-plications, especially when high rate capability is especially important. Thus, many endeavors have beenconformed to increase the surface and intrinsic electrical conductivity of NVP by coating the active mate-rials with a conductive carbon layer, downsizing the NVP particles, combining the NVP particle with vari-ous carbon materials and ion doping strategy. In this review, to get a better understanding on the sodiumstorage in NVP, we firstly present 4 distinct crystal structures in the temperature range of-30℃-225℃ namely α-NVP, β-NVP, β′-NVP and γ-NVP. Moreover, we give an overview of recent approaches to en-hance the surface electrical conductivity and intrinsic electrical conductivity of NVP. Finally, some poten-tial applications of NVP such as in all-climate environment and PHEV, EV fields have been prospected.
基金financially supported by"135"Projects Fund of CAS-QIBEBT Director Innovation Foundationthe Strategic Priority Research Program of the Chinese Academy of Sciences(Grant no.XDA09010105)+4 种基金the National Natural Science Foundation of China(Grant no.51502319)the Think-Tank Mutual Fund of Qingdao Energy Storage Industry Scientific Researchthe Qingdao Science and Technology Program(17-1-1-26-jch)the Youth Innovation Promotion Association CAS(No.2017253)Qingdao Key Lab of Solar Energy Utilization&Energy Storage Technology
文摘NASICON (Na-super-ionic-conductors)-structured materials have attracted extensive research interest due to their great application potential in secondary batteries. However, the mechanism of capacity fading for NASICON-structured electrode materials has been rarely studied. In this paper, we synthesized the NASICON-structured Na3V2(PO4)3/C composite by simple sol-gel and high-temperature solid-phase method and investigated its electrochemical performance in Na-Zn hybrid aqueous rechargeable batteries. After characterizing the structure, morphology and composition variations as well as the interfacial resistance changes of Na3V2(PO4)3/C cathode during cycling, we propose a mechanical and interfacial degradation mechanism for capacity fading of NASICON-structured Na3V2(PO4)3/C in Na-Zn hybrid aqueous rechargeable batteries. This work will shed light on enhancing the mechanical and in terfacial stability of NASICON-structured Na3V2(PO4)3/C in Na-Zn hybrid aqueous rechargeable batteries.
