Layered double hydroxides(LDHs)are potential cathode materials for aqueous magnesium-ion batteries(AMIBs).However,the low capacity and sluggish kinetics significantly limit their electrochemical performance in AMIBs.H...Layered double hydroxides(LDHs)are potential cathode materials for aqueous magnesium-ion batteries(AMIBs).However,the low capacity and sluggish kinetics significantly limit their electrochemical performance in AMIBs.Herein,we find that oxygen vacancies can significantly boost the capacity,electrochemical kinetics,and structure stability of LDHs.The corresponding structure-performance relationship and energy storage mechanism are elaborated through exhaustive in/ex-situ experimental characterizations and density functional theory(DFT)calculations.Specially,in-situ Raman and DFT calculations reveal that oxygen vacancies elevate orbital energy of O 2p and electron density of O atoms,thereby enhancing the orbital hybridization of O 2p with Ni/Co 3d.This facilitates electron transfer between O and adjacent Ni/Co atoms and improves the covalency of Ni–O and Co–O bonds,which activates Ni/Co atoms to release more capacity and stabilizes the Ov-NiCo-LDH structure.Moreover,the distribution of relaxation times(DRT)and molecular dynamics(MD)simulations disclose that the enhanced d-p orbital hybridization optimizes the electronic structure of Ov-NiCo-LDH,which distinctly reduces the diffusion energy barriers of Mg^(2+)and improves the charge transfer kinetics of Ov-NiCo-LDH.Consequently,the assembled Ov-NiCo-LDH//active carbon(AC)and Ov-NiCo-LDH//perylenediimide(PTCDI)AMIBs can both deliver high specific discharge capacity(182.7 and 59.4 mAh g^(−1)at 0.5 A g^(−1),respectively)and long-term cycling stability(85.4%and 89.0%of capacity retentions after 2500 and 2400 cycles at 1.0 A g^(−1),respectively).In addition,the practical prospects for Ov-NiCo-LDH-based AMIBs have been demonstrated in different application scenarios.This work not only provides an effective strategy for obtaining high-performance cathodes of AMIBs,but also fundamentally elucidates the inherent mechanisms.展开更多
Air-rechargeable aqueous Zn-based batteries(ARAZBBs)possess their typical air self-charge advantage.Unfortunately,their further development is beset by two major challenges:an ultrashort air-charge lifespan due to the...Air-rechargeable aqueous Zn-based batteries(ARAZBBs)possess their typical air self-charge advantage.Unfortunately,their further development is beset by two major challenges:an ultrashort air-charge lifespan due to the formation of'dead Zn'(basic zinc salt,BZS)deposited on the cathode surface and the severe corrosion of Zn anode due to continuous consumption of Zn during the air-charge process.Aiming at untying these Gordian knots,herein,an effective dead-zinc activation method of in-situ electrochemical conversion successfully activates'dead zinc'in BZS and repairs the Zn anode simultaneously.Specifically,the specific discharge capacity of as-prepared nitrogen-doped hierarchically porous carbon(NHPC)declines rapidly from 132.4 to 36.8 mAh g^(-1)at 0.2 A g^(-1)after only the 5th air-charge due to a large amount of dead zinc formation.To recover these failed NHPC electrodes,we skillfully draw support from in-situ electrochemical conversion to successfully eliminate BZS on the NHPC during the galvanostatic charging process.More importantly,the method also recovers Zn resources from'dead zinc'to well repair Zn anode,providing a viable solution to address the issue of continuous consumption of Zn.As a result,the air-rechargeable specific capacity of NHPC has been significantly improved from 36.8 to118.9 mAh g^(-1)at 0.2 A g^(-1)by using this effective dead-zinc activation method.Meanwhile,related mechanisms to charge-storage,air-charge,and in-situ electrochemical conversion are clearly revealed by a series of in-/ex-situ tests.This work lays the foundation for the wider practical application of ARAZBBs.展开更多
Transition metal selenides hold great promise as anode materials for obtaining excellent sodium ion batteries.However,the volume expansion effect during charging and discharging severely affects its application.In res...Transition metal selenides hold great promise as anode materials for obtaining excellent sodium ion batteries.However,the volume expansion effect during charging and discharging severely affects its application.In response,we propose a method to limit the volume expansion of cobalt selenide with carbon nanotubes and enhance electron and sodium ion conductivity by carbon and nitrogen doping.Excellent cycling stability and multiplicative performance were eventually achieved.Specifically,the CoSe_(2)@NC/CNTs have a capacity of 480 mA h g^(−1) at 1 A g^(−1) after 200 cycles.In addition,a capacity of 369 mA h g^(−1) at 10 A g^(−1) can be provided after 800 cycles.Impressively,the CoSe_(2)@NC/CNTs//NVPOF full cell was assembled by combining a CoSe_(2)@NC/CNT anode with a Na_(3)V_(2)(PO_(4))_(2)O_(2)F(denoted as NVPOF)cathode with a high capacity of 233 mA h g^(−1) at 0.1 A g^(−1).In addition,the assembled full sodium ion cell had a maximum energy density of 113 W h kg^(−1) and a peak power density of 207 W kg^(−1),making CoSe_(2)@NC/CNTs a promising anode material for high performance sodium ion batteries.展开更多
Titanium niobium oxide as an electrode material for lithium-ion batteries(LIBs)has relatively high working potential and theoretical capacity,which is expected to replace a graphite anode.However,it possesses low elec...Titanium niobium oxide as an electrode material for lithium-ion batteries(LIBs)has relatively high working potential and theoretical capacity,which is expected to replace a graphite anode.However,it possesses low electronic conductivity,leading to the internal electrochemical polarization of the battery during high current charging,which is mainly reflected in the large difference between the actual electrode capacity and the theoretical capacity.展开更多
Herein,in situ chemical anchoring of nickel cobalt selenide(Ni_(3)Se_(4)/CoSe_(2))on two-dimensional(2D)black phosphorene is creatively proposed via a facile approach.The introduction of 2D black phosphorene brings ab...Herein,in situ chemical anchoring of nickel cobalt selenide(Ni_(3)Se_(4)/CoSe_(2))on two-dimensional(2D)black phosphorene is creatively proposed via a facile approach.The introduction of 2D black phosphorene brings abundant interfacial effects and provides fully exposed active sites.The construction of such a heterogeneous structure(BP@Ni_(3)Se_(4)/CoSe_(2))effectively buffers the volume expansion effect caused by Na ion insertion and promotes electron/ion transfer during cycling.Therefore,the BP@Ni_(3)Se_(4)/CoSe_(2)electrode exhibits superior sodium storage properties in half cells,such as a high stable discharge specific capacity(about 358.8 mA h g^(-1)at 1 A g^(-1)after 100 cycles),excellent cycling stability(up to 2500 cycles,the capacity retention rate close to 82%)and high rate performance(from the initial 0.2 A g^(-1)to the final 20 A g^(-1)and the total capacity retention rate is about 76%).In addition,BP@Ni_(3)Se_(4)/CoSe_(2)achieved a high energy density of 163.7 W h kg^(-1)at the power density of 136.4 W kg^(-1)in the sodium-ion battery full battery test.Such high performance of BP@Ni_(3)Se_(4)/CoSe_(2)is attributed to its excellent reaction kinetic characteristics.The investigation of the sodium storage mechanism of BP@Ni_(3)Se_(4)/CoSe_(2)is conducted in detail.展开更多
基金financial support of the National Natural Science Foundation of China (22379063)
文摘Layered double hydroxides(LDHs)are potential cathode materials for aqueous magnesium-ion batteries(AMIBs).However,the low capacity and sluggish kinetics significantly limit their electrochemical performance in AMIBs.Herein,we find that oxygen vacancies can significantly boost the capacity,electrochemical kinetics,and structure stability of LDHs.The corresponding structure-performance relationship and energy storage mechanism are elaborated through exhaustive in/ex-situ experimental characterizations and density functional theory(DFT)calculations.Specially,in-situ Raman and DFT calculations reveal that oxygen vacancies elevate orbital energy of O 2p and electron density of O atoms,thereby enhancing the orbital hybridization of O 2p with Ni/Co 3d.This facilitates electron transfer between O and adjacent Ni/Co atoms and improves the covalency of Ni–O and Co–O bonds,which activates Ni/Co atoms to release more capacity and stabilizes the Ov-NiCo-LDH structure.Moreover,the distribution of relaxation times(DRT)and molecular dynamics(MD)simulations disclose that the enhanced d-p orbital hybridization optimizes the electronic structure of Ov-NiCo-LDH,which distinctly reduces the diffusion energy barriers of Mg^(2+)and improves the charge transfer kinetics of Ov-NiCo-LDH.Consequently,the assembled Ov-NiCo-LDH//active carbon(AC)and Ov-NiCo-LDH//perylenediimide(PTCDI)AMIBs can both deliver high specific discharge capacity(182.7 and 59.4 mAh g^(−1)at 0.5 A g^(−1),respectively)and long-term cycling stability(85.4%and 89.0%of capacity retentions after 2500 and 2400 cycles at 1.0 A g^(−1),respectively).In addition,the practical prospects for Ov-NiCo-LDH-based AMIBs have been demonstrated in different application scenarios.This work not only provides an effective strategy for obtaining high-performance cathodes of AMIBs,but also fundamentally elucidates the inherent mechanisms.
基金financial support of the National Natural Science Foundation of China(22379063)。
文摘Air-rechargeable aqueous Zn-based batteries(ARAZBBs)possess their typical air self-charge advantage.Unfortunately,their further development is beset by two major challenges:an ultrashort air-charge lifespan due to the formation of'dead Zn'(basic zinc salt,BZS)deposited on the cathode surface and the severe corrosion of Zn anode due to continuous consumption of Zn during the air-charge process.Aiming at untying these Gordian knots,herein,an effective dead-zinc activation method of in-situ electrochemical conversion successfully activates'dead zinc'in BZS and repairs the Zn anode simultaneously.Specifically,the specific discharge capacity of as-prepared nitrogen-doped hierarchically porous carbon(NHPC)declines rapidly from 132.4 to 36.8 mAh g^(-1)at 0.2 A g^(-1)after only the 5th air-charge due to a large amount of dead zinc formation.To recover these failed NHPC electrodes,we skillfully draw support from in-situ electrochemical conversion to successfully eliminate BZS on the NHPC during the galvanostatic charging process.More importantly,the method also recovers Zn resources from'dead zinc'to well repair Zn anode,providing a viable solution to address the issue of continuous consumption of Zn.As a result,the air-rechargeable specific capacity of NHPC has been significantly improved from 36.8 to118.9 mAh g^(-1)at 0.2 A g^(-1)by using this effective dead-zinc activation method.Meanwhile,related mechanisms to charge-storage,air-charge,and in-situ electrochemical conversion are clearly revealed by a series of in-/ex-situ tests.This work lays the foundation for the wider practical application of ARAZBBs.
基金supported by the National Natural Science Foundation of China(51801030)Natural Science Foundation of Jiangsu Province(BK20191030)+3 种基金Agriculture Science and Technology Innovation Project of Suzhou(SNG2021034)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(20KJA430006)Science and Technology Development Plan of Suzhou(ZXL2021176)supported by Jiangsu Provincial Founds for the Young Scholars(BK20190978).
文摘Transition metal selenides hold great promise as anode materials for obtaining excellent sodium ion batteries.However,the volume expansion effect during charging and discharging severely affects its application.In response,we propose a method to limit the volume expansion of cobalt selenide with carbon nanotubes and enhance electron and sodium ion conductivity by carbon and nitrogen doping.Excellent cycling stability and multiplicative performance were eventually achieved.Specifically,the CoSe_(2)@NC/CNTs have a capacity of 480 mA h g^(−1) at 1 A g^(−1) after 200 cycles.In addition,a capacity of 369 mA h g^(−1) at 10 A g^(−1) can be provided after 800 cycles.Impressively,the CoSe_(2)@NC/CNTs//NVPOF full cell was assembled by combining a CoSe_(2)@NC/CNT anode with a Na_(3)V_(2)(PO_(4))_(2)O_(2)F(denoted as NVPOF)cathode with a high capacity of 233 mA h g^(−1) at 0.1 A g^(−1).In addition,the assembled full sodium ion cell had a maximum energy density of 113 W h kg^(−1) and a peak power density of 207 W kg^(−1),making CoSe_(2)@NC/CNTs a promising anode material for high performance sodium ion batteries.
基金supported by the Natural Science Foundation of the Jiangsu Higher Education Institutions(22KJA430009)the Science and Technology Development Plan of Suzhou(ZXL2022176)the China Postdoctoral Science Foundation(2022M711686).
文摘Titanium niobium oxide as an electrode material for lithium-ion batteries(LIBs)has relatively high working potential and theoretical capacity,which is expected to replace a graphite anode.However,it possesses low electronic conductivity,leading to the internal electrochemical polarization of the battery during high current charging,which is mainly reflected in the large difference between the actual electrode capacity and the theoretical capacity.
基金supported by the National Natural Science Foundation of China(62174016)the Natural Science Foundation of the Jiangsu Higher Education Institutions(22KJA430009)+2 种基金the Science and Technology Development Plan of Suzhou(ZXL2022176)the China Postdoctoral Science Foundation(2022M711686)the Jiangsu Provincial Funds for the Young Scholars(BK20190978).
文摘Herein,in situ chemical anchoring of nickel cobalt selenide(Ni_(3)Se_(4)/CoSe_(2))on two-dimensional(2D)black phosphorene is creatively proposed via a facile approach.The introduction of 2D black phosphorene brings abundant interfacial effects and provides fully exposed active sites.The construction of such a heterogeneous structure(BP@Ni_(3)Se_(4)/CoSe_(2))effectively buffers the volume expansion effect caused by Na ion insertion and promotes electron/ion transfer during cycling.Therefore,the BP@Ni_(3)Se_(4)/CoSe_(2)electrode exhibits superior sodium storage properties in half cells,such as a high stable discharge specific capacity(about 358.8 mA h g^(-1)at 1 A g^(-1)after 100 cycles),excellent cycling stability(up to 2500 cycles,the capacity retention rate close to 82%)and high rate performance(from the initial 0.2 A g^(-1)to the final 20 A g^(-1)and the total capacity retention rate is about 76%).In addition,BP@Ni_(3)Se_(4)/CoSe_(2)achieved a high energy density of 163.7 W h kg^(-1)at the power density of 136.4 W kg^(-1)in the sodium-ion battery full battery test.Such high performance of BP@Ni_(3)Se_(4)/CoSe_(2)is attributed to its excellent reaction kinetic characteristics.The investigation of the sodium storage mechanism of BP@Ni_(3)Se_(4)/CoSe_(2)is conducted in detail.
