Sodium-ion batteries are promising candidates for next-generation large-scale energy storage owing to their abundance and low cost.Biphasic intercalation reactions,constrained by kinetic limitations and structural ins...Sodium-ion batteries are promising candidates for next-generation large-scale energy storage owing to their abundance and low cost.Biphasic intercalation reactions,constrained by kinetic limitations and structural instability,fundamentally restrict the rate capability and cycle life of sodium ion batteries.However,precise regulation of these reactions to enhance kinetics remains challenging.Here,we propose a strategy of atomic-scale phase engineering to activate the metastable state and achieve a three-phase reaction through precise Mg^(2+)doping at V sites in Na_(3)V_(2)(PO_(4))_(3).The Mg^(2+)occupancy promotes the exchange between Na1 and Na2 sites,thereby stabilizing a Na_(2)V_(2)(PO_(4))_(3) intermediate.First-principles calculations indicate that Mg^(2+)occupation facilitates charge redistribution by weakening Na-O electrostatic interaction,stabilizing the formation of Na_(2)V_(2)(PO_(4))_(3)phase.The optimized cathode exhibits ultrahigh capacity retention(84.5%after 5000 cycles at 3.51 A g^(-1)),supports ultrafast charging within 120 s,and exceptional rate capability(96.2 mAh g^(-1)at 4.68 A g^(-1)).This work establishes a universal route to unlock hidden reaction pathways by redefining the role of dopants in phase transition control.展开更多
基金finally supported by the National Natural Science Foundation of China(NSFC Grants 52074098)the Major Science and Technology R&D Special Project in Jiangxi Province(104 Ah high specific energy and fast charging function lithium-ion battery system development and application project 20233AAE02009)the Cospowers Technology Co.,Ltd.,Technology Project Funding(research on key materials and battery technologies for sodium ion batteries,KYDY2022003)。
文摘Sodium-ion batteries are promising candidates for next-generation large-scale energy storage owing to their abundance and low cost.Biphasic intercalation reactions,constrained by kinetic limitations and structural instability,fundamentally restrict the rate capability and cycle life of sodium ion batteries.However,precise regulation of these reactions to enhance kinetics remains challenging.Here,we propose a strategy of atomic-scale phase engineering to activate the metastable state and achieve a three-phase reaction through precise Mg^(2+)doping at V sites in Na_(3)V_(2)(PO_(4))_(3).The Mg^(2+)occupancy promotes the exchange between Na1 and Na2 sites,thereby stabilizing a Na_(2)V_(2)(PO_(4))_(3) intermediate.First-principles calculations indicate that Mg^(2+)occupation facilitates charge redistribution by weakening Na-O electrostatic interaction,stabilizing the formation of Na_(2)V_(2)(PO_(4))_(3)phase.The optimized cathode exhibits ultrahigh capacity retention(84.5%after 5000 cycles at 3.51 A g^(-1)),supports ultrafast charging within 120 s,and exceptional rate capability(96.2 mAh g^(-1)at 4.68 A g^(-1)).This work establishes a universal route to unlock hidden reaction pathways by redefining the role of dopants in phase transition control.
