The development of new sodium ion battery （SIB） cathodes with satisfactory performance requires an in-depth understanding of their structure-function relationships, to rationally design better electrode materials. I...The development of new sodium ion battery （SIB） cathodes with satisfactory performance requires an in-depth understanding of their structure-function relationships, to rationally design better electrode materials. In this work highly ordered, honeycomb-layered Na3Ni2SbO6 was prepared to elucidate the structural evolution and Na~ kinetics during electrochemical desodiation/sodiation processes. Structural analysis involving in situ synchrotron X-ray diffraction （XRD） experiments, electrochemical performance measurements, and electrochemical characterization （galvanostatic intermittent titration technique, GITT） methods were used to obtain new insights into the reaction mechanism controlling the （de）intercalation of sodium into the host NaB-xNi2SbO6 structure. Two phase transitions occur （initial O＇3 phase → intermediate P＇3 phase→final O1 phase） upon Na^＋ extraction; the partial irreversible O＇3-P＇3 phase transition is responsible for the insufficient cycling stability. The fast Na^＋ mobility （average 10^-12 cm^2·s^-1） in the interlayer, high equilibrium voltage （3.27 V）, and low voltage polarization （50 mV） establish the linkage between kinetic advantage and a good rate performance of the cathode. These new findings provide deep insight into the reaction mechanism operating in the honeycomb cathode; the present approach could be also extended to investigate other materials for SIBs.展开更多
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
文摘The development of new sodium ion battery （SIB） cathodes with satisfactory performance requires an in-depth understanding of their structure-function relationships, to rationally design better electrode materials. In this work highly ordered, honeycomb-layered Na3Ni2SbO6 was prepared to elucidate the structural evolution and Na~ kinetics during electrochemical desodiation/sodiation processes. Structural analysis involving in situ synchrotron X-ray diffraction （XRD） experiments, electrochemical performance measurements, and electrochemical characterization （galvanostatic intermittent titration technique, GITT） methods were used to obtain new insights into the reaction mechanism controlling the （de）intercalation of sodium into the host NaB-xNi2SbO6 structure. Two phase transitions occur （initial O＇3 phase → intermediate P＇3 phase→final O1 phase） upon Na^＋ extraction; the partial irreversible O＇3-P＇3 phase transition is responsible for the insufficient cycling stability. The fast Na^＋ mobility （average 10^-12 cm^2·s^-1） in the interlayer, high equilibrium voltage （3.27 V）, and low voltage polarization （50 mV） establish the linkage between kinetic advantage and a good rate performance of the cathode. These new findings provide deep insight into the reaction mechanism operating in the honeycomb cathode; the present approach could be also extended to investigate other materials for SIBs.
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.
