High safety and high energy-density sodium-ion batteries require the promising polyanionic insertion-type cathode possessing fast dis-/charging capability,yet persistent challenges remain in the kinetic optimization t...High safety and high energy-density sodium-ion batteries require the promising polyanionic insertion-type cathode possessing fast dis-/charging capability,yet persistent challenges remain in the kinetic optimization to accelerate their intrinsically low Na^(+)diffusivity.Exampled by the representative Na_(3)V_(2)(PO_(4))O_(2)F(NVPOF)with considerable theoretical energy density,structural distortion results in a one-dimensional sluggish Nat diffusion out of the two-dimensional Na pathway provided structurally.Previous endeavors with Na site or transition-metal site regulation successfully optimize the Na^(+)diffusion energy barrier of the available one-dimensional path.However,these substituted elements with non-equivalent valances or sizes further elevate the energy barrier of the other unavailable Na^(+)diffusion path.Herein,by defining the independently accessible Na^(+)diffusion pathways in the crystallographic structure as Na^(+) diffusion degree of freedom(df_([Na^(+)])),we demonstrate broadening df_([Na^(+)])to two in NVPOF by a mild perturb at the dangling site can fundamentally revise the Na diffusion behaviour.As demonstrated by in-situ synchrotron,various spectroscopic techniques,and density functional theory(DFT)modeling,this mild perturb equalizes the Na^(+) diffusion energy barriers along a and b directions and enables two-dimensional Nat transportation.The as-prepared NvPOF depicts an altered solid-solution phase transition,higher disorder in the framework and dramatically enhanced Na diffusivity,which leads to unprecedentedly high sodium storage properties in half cell(68.6 mAh g^(-1) at 100 C;103.3 mAh g^(-1) after 1300 cycles at 20 C;1 C=130 mA g^(-1))and full cell(313.8 Wh kg^(-1)@4063.5 W kg^(-1);113.9 Wh kg^(-1)@16,397.2 W kg^(-1)).This study enlightens the valuable role of broadening df_([Na^(+)])in fundamentally maximizing the polyanionic insertion-type performance.展开更多
Solid solutions(SS)with a quasi-binary cross-section of a four-component system of the composition(1-x)(Na_(0.5)K_(0.5))NbO_(3)-xPb(Ti_(0.5)Zr_(0.5))O_(3),based on compositions with fundamentally different physical re...Solid solutions(SS)with a quasi-binary cross-section of a four-component system of the composition(1-x)(Na_(0.5)K_(0.5))NbO_(3)-xPb(Ti_(0.5)Zr_(0.5))O_(3),based on compositions with fundamentally different physical responses(Na,K)NbO_(3)(KNN),Pb(Ti,Zr)O_(3)(PZT),have been prepared by a two-stage solid-phase synthesis followed by sintering using conventional ceramic technology.The influence of thermal cycling on the dielectric properties of ceramic SS with x=0.00,...,1.00 has been studied.It has been shown that thermally induced fatigue does not have a significant effect on the Curie temperature and the diffusing of the phase transition(PT)of SS containing only extreme components.It has been found that when the concentration of PZT in the studied system is varied,the e'leo(T)dependencies take on a form characteristic offerroelectrics with a diffuse PT.When the repolarisation cycles are varied,the diffusing parameter and the Curie and Burns temperatures show a wave-like behavior.The observed effects are explained by the interaction of different defect types.A conclusion is drawn on the possible practical applications of the studied Ss.展开更多
基金supported by the National Natural Science Foundation of China(52272091)Agency for Science,Technology and Research(A*STAR)through Low Carbon Energy Research Finding Initiative(LCERFI01-0033|U2102d2006)+3 种基金A*STAR MTC programmatic project(M23L9b0052)Indonesia-NTU Singapore Institute of Research for Sustainability and Innovation(INSPIRASI)(6635/E3/KL.02.02/2023)Singapore NRF Singapore-China flagship program(023740-00001)Natural Science Foundation of Jiangxi Province(20232ACB214001).
文摘High safety and high energy-density sodium-ion batteries require the promising polyanionic insertion-type cathode possessing fast dis-/charging capability,yet persistent challenges remain in the kinetic optimization to accelerate their intrinsically low Na^(+)diffusivity.Exampled by the representative Na_(3)V_(2)(PO_(4))O_(2)F(NVPOF)with considerable theoretical energy density,structural distortion results in a one-dimensional sluggish Nat diffusion out of the two-dimensional Na pathway provided structurally.Previous endeavors with Na site or transition-metal site regulation successfully optimize the Na^(+)diffusion energy barrier of the available one-dimensional path.However,these substituted elements with non-equivalent valances or sizes further elevate the energy barrier of the other unavailable Na^(+)diffusion path.Herein,by defining the independently accessible Na^(+)diffusion pathways in the crystallographic structure as Na^(+) diffusion degree of freedom(df_([Na^(+)])),we demonstrate broadening df_([Na^(+)])to two in NVPOF by a mild perturb at the dangling site can fundamentally revise the Na diffusion behaviour.As demonstrated by in-situ synchrotron,various spectroscopic techniques,and density functional theory(DFT)modeling,this mild perturb equalizes the Na^(+) diffusion energy barriers along a and b directions and enables two-dimensional Nat transportation.The as-prepared NvPOF depicts an altered solid-solution phase transition,higher disorder in the framework and dramatically enhanced Na diffusivity,which leads to unprecedentedly high sodium storage properties in half cell(68.6 mAh g^(-1) at 100 C;103.3 mAh g^(-1) after 1300 cycles at 20 C;1 C=130 mA g^(-1))and full cell(313.8 Wh kg^(-1)@4063.5 W kg^(-1);113.9 Wh kg^(-1)@16,397.2 W kg^(-1)).This study enlightens the valuable role of broadening df_([Na^(+)])in fundamentally maximizing the polyanionic insertion-type performance.
文摘Solid solutions(SS)with a quasi-binary cross-section of a four-component system of the composition(1-x)(Na_(0.5)K_(0.5))NbO_(3)-xPb(Ti_(0.5)Zr_(0.5))O_(3),based on compositions with fundamentally different physical responses(Na,K)NbO_(3)(KNN),Pb(Ti,Zr)O_(3)(PZT),have been prepared by a two-stage solid-phase synthesis followed by sintering using conventional ceramic technology.The influence of thermal cycling on the dielectric properties of ceramic SS with x=0.00,...,1.00 has been studied.It has been shown that thermally induced fatigue does not have a significant effect on the Curie temperature and the diffusing of the phase transition(PT)of SS containing only extreme components.It has been found that when the concentration of PZT in the studied system is varied,the e'leo(T)dependencies take on a form characteristic offerroelectrics with a diffuse PT.When the repolarisation cycles are varied,the diffusing parameter and the Curie and Burns temperatures show a wave-like behavior.The observed effects are explained by the interaction of different defect types.A conclusion is drawn on the possible practical applications of the studied Ss.
