Sodium titanium phosphate(NaTi_(2)(PO_(4))_(3),NTP)has emerged as a promising electrode material due to its three-dimensional open framework.This study investigates the use of NTP in aqueous dilute Li^(+)/Na^(+)electr...Sodium titanium phosphate(NaTi_(2)(PO_(4))_(3),NTP)has emerged as a promising electrode material due to its three-dimensional open framework.This study investigates the use of NTP in aqueous dilute Li^(+)/Na^(+)electrolytes and extends its application to high-concentration K+electrolytes.X-ray photoelectron spectroscopy,X-ray absorption near-edge structure analysis,and density functional theory calculations revealed that highly electronegative fluorine partially substitutes for oxygen in the NTP lattice,resulting in the formation of Ti-F bonds.The substitution effectively modulates the electronic structure of Ti^(4+),alters the local coordination environment,and influences the redox dynamics.Enhanced long-term cycling stability and rate performance were demonstrated across aqueous sodium-ion,lithium-ion,and potassium-ion half-cells.Among the investigated systems,the aqueous sodium-ion system exhibited the best electrochemical performance,characterized by a single,well-defined charge–discharge plateau,stable cycling behavior with 88.7%capacity retention after 500 cycles at 1 A g^(−1),and an initial specific discharge capacity of 121.7 mAh g^(−1) at 0.2 A g^(−1).The results establish F-doped NTP as a promising candidate for advanced energy storage applications in aqueous alkali metal-ion batteries.展开更多
NaTi_(2)(PO_(4))_(3)(NTP)is a material with a NASICON structure,a three-dimensional open type skeleton,and suitable negative voltage window,which is widely regarded as a magnetic anode material for aqueous sodium ion ...NaTi_(2)(PO_(4))_(3)(NTP)is a material with a NASICON structure,a three-dimensional open type skeleton,and suitable negative voltage window,which is widely regarded as a magnetic anode material for aqueous sodium ion batteries(ASIBs).However,NTP’s in-trinsically poor conductivity hampers their use in ASIBs.Herein,bimetallic doped carbon material was designed and combined with the sol-gel method to prepare NaTi_(2)(PO_(4))_(3)-C-FeNi(NTP-C-FeNi)composite materials.This bimetallic doped carbon composite NTP ma-terial not only has a large specific surface area,but also effectively improves conductivity and promotes rapid migration of Na^(+).Follow-ing the rate performance test,NTP-C-FeNi retained a reversible capacity of 116.75 mAh·g^(-1) at 0.1 A·g^(-1),representing 95.9%of the first cycle capacity.After 500 cycles at 1.5 A·g^(-1),the cycle fixity was 85.3%.The enhancement of electrochemical performance may owe to the widening of pathways and acceleration of Na^(+)insertion/extraction facilitated by FeNi-C doping,while the carbon coating effectively promotes electrode charge transfer.The results indicate that the bimetallic doped carbon composite NaTi_(2)(PO_(4))_(3) holds potential for prac-tical applications in novel aqueous sodium ion battery systems.展开更多
This paper describes the spatial transmission of electromagnetically induced transparency and four-wave mixing signals in the photonic bandgap structure,which are modulated using the adjustable parameters of light fie...This paper describes the spatial transmission of electromagnetically induced transparency and four-wave mixing signals in the photonic bandgap structure,which are modulated using the adjustable parameters of light fields.The spatial transmission patterns of the relevant signals are experimentally investigated with respect to the optical nonlinear Kerr effect that occurs in the modulation process.The experimental results reveal the spatial transmission patterns of the probe transmission and the four-wave mixing signals,such as focusing,defocusing,shifting,and spatial splitting.This study explains how the tunable parameters of light fields and their interactions with each other can regulate the spatial transmission of the light fields by changing the refractive indices of media,which provides a new research perspective and a degree of experimental technology support for more efficient all-optical communications.展开更多
基金supported by the National Natural Science Foundation of China(52072298,51802261,11675129)the Natural Science Basic Research Plan in Shaanxi Province of China(2025JC-YBQN-758)+1 种基金Scientific Research Program Funded by Shaanxi Provincial Education Department(Program No.23JK0662)the Youth Innovation Team of Shaanxi Universities.
文摘Sodium titanium phosphate(NaTi_(2)(PO_(4))_(3),NTP)has emerged as a promising electrode material due to its three-dimensional open framework.This study investigates the use of NTP in aqueous dilute Li^(+)/Na^(+)electrolytes and extends its application to high-concentration K+electrolytes.X-ray photoelectron spectroscopy,X-ray absorption near-edge structure analysis,and density functional theory calculations revealed that highly electronegative fluorine partially substitutes for oxygen in the NTP lattice,resulting in the formation of Ti-F bonds.The substitution effectively modulates the electronic structure of Ti^(4+),alters the local coordination environment,and influences the redox dynamics.Enhanced long-term cycling stability and rate performance were demonstrated across aqueous sodium-ion,lithium-ion,and potassium-ion half-cells.Among the investigated systems,the aqueous sodium-ion system exhibited the best electrochemical performance,characterized by a single,well-defined charge–discharge plateau,stable cycling behavior with 88.7%capacity retention after 500 cycles at 1 A g^(−1),and an initial specific discharge capacity of 121.7 mAh g^(−1) at 0.2 A g^(−1).The results establish F-doped NTP as a promising candidate for advanced energy storage applications in aqueous alkali metal-ion batteries.
基金supported by the National Natural Science Foundation of China(Nos.52072298 and 51802261)the Scientific Research Program Funded by Shaanxi Provincial Education Department,China(No.23JK0662)+1 种基金the Natural Science Foundation of Shaanxi Province,China(Nos.2023-JC-YB-515 and 2025JC-YBQN-758)the Youth Innovation Team of Shaanxi Universities.
文摘NaTi_(2)(PO_(4))_(3)(NTP)is a material with a NASICON structure,a three-dimensional open type skeleton,and suitable negative voltage window,which is widely regarded as a magnetic anode material for aqueous sodium ion batteries(ASIBs).However,NTP’s in-trinsically poor conductivity hampers their use in ASIBs.Herein,bimetallic doped carbon material was designed and combined with the sol-gel method to prepare NaTi_(2)(PO_(4))_(3)-C-FeNi(NTP-C-FeNi)composite materials.This bimetallic doped carbon composite NTP ma-terial not only has a large specific surface area,but also effectively improves conductivity and promotes rapid migration of Na^(+).Follow-ing the rate performance test,NTP-C-FeNi retained a reversible capacity of 116.75 mAh·g^(-1) at 0.1 A·g^(-1),representing 95.9%of the first cycle capacity.After 500 cycles at 1.5 A·g^(-1),the cycle fixity was 85.3%.The enhancement of electrochemical performance may owe to the widening of pathways and acceleration of Na^(+)insertion/extraction facilitated by FeNi-C doping,while the carbon coating effectively promotes electrode charge transfer.The results indicate that the bimetallic doped carbon composite NaTi_(2)(PO_(4))_(3) holds potential for prac-tical applications in novel aqueous sodium ion battery systems.
基金Project supported by the National Natural Science Foundation of China(Grant No.61705182)the Natural Science Foundation of Shaanxi Province,China(Grant No.2017JQ6024)
文摘This paper describes the spatial transmission of electromagnetically induced transparency and four-wave mixing signals in the photonic bandgap structure,which are modulated using the adjustable parameters of light fields.The spatial transmission patterns of the relevant signals are experimentally investigated with respect to the optical nonlinear Kerr effect that occurs in the modulation process.The experimental results reveal the spatial transmission patterns of the probe transmission and the four-wave mixing signals,such as focusing,defocusing,shifting,and spatial splitting.This study explains how the tunable parameters of light fields and their interactions with each other can regulate the spatial transmission of the light fields by changing the refractive indices of media,which provides a new research perspective and a degree of experimental technology support for more efficient all-optical communications.
