As a promising cathode material for sodium ion batteries,honeycomb-ordered layered Na_(3)Ni_(2)Sb O_(6)still suffers from rapid capacity fading because of partially irreversible phase transition.Herein,a substitution ...As a promising cathode material for sodium ion batteries,honeycomb-ordered layered Na_(3)Ni_(2)Sb O_(6)still suffers from rapid capacity fading because of partially irreversible phase transition.Herein,a substitution of Na+by Rb+with a larger ionic radius in honeycomb layered Na_(3)-xRbxNi_(2)Sb O_(6)is proposed to modulate the interlayer structure.The results unveil that biphasic transition reversibility of the intermediate P′3phase is substantially enhanced,and the structure evolution behavior during the charge/discharge process changes due to the structural modulation,which contributes to a suppression of the unfavorable O_(1)phase and an alleviation of the lattice distortion.Moreover,Rb substituted samples exhibited an improved Na+(de)intercalation thermodynamics and kinetics.Attributed to the modifications,the sample with optimized Rb content delivers superior cycle stability and rate capacity,demonstrating a feasible strategy for suppressing irreversible phase transition and developing high-performance honeycomb layered materials for sodium ion batteries.展开更多
Brannerite-type NaVMoO6 with vanadium(V5+) and molybdenum(Mo6+) elements in the highest valence states is synthesized by a sol-gel method using Na2CO3, NH4VO3, MoO3 and citric acid reagents. The results of X-ray diffr...Brannerite-type NaVMoO6 with vanadium(V5+) and molybdenum(Mo6+) elements in the highest valence states is synthesized by a sol-gel method using Na2CO3, NH4VO3, MoO3 and citric acid reagents. The results of X-ray diffraction(XRD) with Rietveld refinement and X-ray photoelectron spectroscopy(XPS) show that the obtained NaVMoO6 sample is single-phase. Novel electrode material(NaVMoO6) with layered structure is first utilized as cathode material for lithium ion batteries(LIBs). The NaVMoO6 electrode delivers reversible specific capacity of 126.4 mA h g-1 at 5 mA g-1 after 50 cycles. The stable structure of NaVMoO6 is corroborated by ex-situ XRD, suggesting that this material is considered as a prospective cathode for LIBs. This studying enriches the possibilities of molybdenum-based materials as cathodes for LIBs.展开更多
基金funded by the NSFC Grant(52177213)supported through NSFC Committee of Chinathe foundation(2020A1414010346 and 2019622163008)supported through the Science and Technology Bureau of Guangdong Governmentsponsored by the Student Research Program(X202110561688)supported through South China University of Technology。
文摘As a promising cathode material for sodium ion batteries,honeycomb-ordered layered Na_(3)Ni_(2)Sb O_(6)still suffers from rapid capacity fading because of partially irreversible phase transition.Herein,a substitution of Na+by Rb+with a larger ionic radius in honeycomb layered Na_(3)-xRbxNi_(2)Sb O_(6)is proposed to modulate the interlayer structure.The results unveil that biphasic transition reversibility of the intermediate P′3phase is substantially enhanced,and the structure evolution behavior during the charge/discharge process changes due to the structural modulation,which contributes to a suppression of the unfavorable O_(1)phase and an alleviation of the lattice distortion.Moreover,Rb substituted samples exhibited an improved Na+(de)intercalation thermodynamics and kinetics.Attributed to the modifications,the sample with optimized Rb content delivers superior cycle stability and rate capacity,demonstrating a feasible strategy for suppressing irreversible phase transition and developing high-performance honeycomb layered materials for sodium ion batteries.
基金funded by NSFC Grant (No. 51672086)the Science and Technology Bureau of Guangdong Government (No. 2017B030308005)the project (No. 2019622163008) of the Science and Technology Bureau from Dongguan Government。
文摘Brannerite-type NaVMoO6 with vanadium(V5+) and molybdenum(Mo6+) elements in the highest valence states is synthesized by a sol-gel method using Na2CO3, NH4VO3, MoO3 and citric acid reagents. The results of X-ray diffraction(XRD) with Rietveld refinement and X-ray photoelectron spectroscopy(XPS) show that the obtained NaVMoO6 sample is single-phase. Novel electrode material(NaVMoO6) with layered structure is first utilized as cathode material for lithium ion batteries(LIBs). The NaVMoO6 electrode delivers reversible specific capacity of 126.4 mA h g-1 at 5 mA g-1 after 50 cycles. The stable structure of NaVMoO6 is corroborated by ex-situ XRD, suggesting that this material is considered as a prospective cathode for LIBs. This studying enriches the possibilities of molybdenum-based materials as cathodes for LIBs.
