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
Sustainable development has long been recognized as one of the most critical issues in today’s energy and environment-conscious society.It has never been more urgent to recycle and reuse the end-of-life cathode mater...Sustainable development has long been recognized as one of the most critical issues in today’s energy and environment-conscious society.It has never been more urgent to recycle and reuse the end-of-life cathode materials.Here,this work systematically investigates the structure-critical degradation mechanism of polycrystalline LiNi_(x)Co_(y)Mn_(1−x−y)O_(2)(NCM),combining experimental characterization and DFT simulations.Targeting the key degradation factors,a synergistic repair strategy based on deep mechanochemical activation and heat treatment was successfully proposed to direct regenerate the degradedNCMmaterial.Studies indicate the induction and promotion of synergistic repair technique on the reconstruction of particlemorphology,the recovery of the chemical composition and crystal structure,and the favorable transformation of the impurities phase in the failed materials.In particular,the synergistic repair process induces a gradient distribution of LiF and further enables partial fluorine doping into the NCM surface,forming abundant oxygen vacancies and increasing the content of highly reactive Ni2+.Benefiting from the comprehensive treatment for the multi-scale and multi-form degradation behaviors,the repaired material exhibits a capacity of 176.8 mA h g^(-1)at 0.1 C,which is comparable to the corresponding commercial material(172.8 mA h g^(-1)).The satisfactory capacity of the recovered cathode proves that it is an effective direct renovating strategy.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.
基金National Natural Science Foundation of China,Grant/Award Number:52074098the State Grid Heilongjiang Electric Power Co.,Ltd.,Technology Project Funding,Grant/Award Number:52243723000C+1 种基金Foundation of Key Program of Sci-Tech Innovation in Ningbo,Grant/Award Number:2019B10114Natural Science Foundation of Heilongjiang Province,Grant/Award Number:YQ2021E039。
文摘Sustainable development has long been recognized as one of the most critical issues in today’s energy and environment-conscious society.It has never been more urgent to recycle and reuse the end-of-life cathode materials.Here,this work systematically investigates the structure-critical degradation mechanism of polycrystalline LiNi_(x)Co_(y)Mn_(1−x−y)O_(2)(NCM),combining experimental characterization and DFT simulations.Targeting the key degradation factors,a synergistic repair strategy based on deep mechanochemical activation and heat treatment was successfully proposed to direct regenerate the degradedNCMmaterial.Studies indicate the induction and promotion of synergistic repair technique on the reconstruction of particlemorphology,the recovery of the chemical composition and crystal structure,and the favorable transformation of the impurities phase in the failed materials.In particular,the synergistic repair process induces a gradient distribution of LiF and further enables partial fluorine doping into the NCM surface,forming abundant oxygen vacancies and increasing the content of highly reactive Ni2+.Benefiting from the comprehensive treatment for the multi-scale and multi-form degradation behaviors,the repaired material exhibits a capacity of 176.8 mA h g^(-1)at 0.1 C,which is comparable to the corresponding commercial material(172.8 mA h g^(-1)).The satisfactory capacity of the recovered cathode proves that it is an effective direct renovating strategy.
