The introduction of foreign metals with a higher oxophilicity represents a promising strategy to promote water dissociation and in turn kinetics of alkaline hydrogen evolution reaction(HER).However,the further improve...The introduction of foreign metals with a higher oxophilicity represents a promising strategy to promote water dissociation and in turn kinetics of alkaline hydrogen evolution reaction(HER).However,the further improvement of HER activity is limited by the unfavorable interaction of hydroxyl generated by the dissociation of water with active sites.Herein,we propose a strategy of alkaline earth metal cations-driven electron delocalization to elaborately tailor the binding of hydroxyl with the active sites.Taking FeNiMg-layered double hydroxides(FeNiMg-LDH)as a prototypical example,the combined operando spectroscopy analysis and theoretical calculations show that the introduction of Mg cations in solid-solution phase can create a local electronic field and delocalize the electron between Fe and adsorbed hydroxyl,resulting in an optimization of hydroxyl binding strength.Accordingly,FeNiMg-LDH lowers the overpotentials to deliver 10 mA cm−2 in alkaline electrolyte by 39 and 64 mV,compared to FeNi-LDH and Ni-LDH catalysts,respectively.This work sheds new light on the rational design of advanced HER electrocatalyst for alkaline water electrolysis.展开更多
Solid-state lithium-metal batteries based on poly(vinylidene fluoride-co-hexafluoropropylene)(PVH)are frequently proposed to address the detrimental safety issue of conventional lithium-ion batteries by eliminating th...Solid-state lithium-metal batteries based on poly(vinylidene fluoride-co-hexafluoropropylene)(PVH)are frequently proposed to address the detrimental safety issue of conventional lithium-ion batteries by eliminating the use of flammable solvents,but still face a key challenge:low capacity and sluggish charge/discharge rate due to the intrinsic large-gradient Li^(+)distribution across the ionically-inert PVH matrix.Herein,Te vacancies in form of Bi_(2)Te_(3-x) are proposed to polarize the PVH unit to realize efficient decoupling of lithium salts at the atomic level in PVH-based solid polymeric electrolyte.Te vacancies in the PVH electrolyte doped with Bi_(2)Te_(3-x)(PVBT)induce a high-throughput and homogenous Li^(+)flow within the PVH matrices and near the Li metal.Theoretical calculations show that Te vacancies own high adsorption energy with bis(trifluoromethanesulfonyl)imide anions(TFSI^(-)),repulsive effect on Li^(+),and localized electron distribution,giving rise to a lithium-ion concentration gradient of 30 mol m^(-3),the smallest among the PVH-based inorganic/organic composite electrolytes.Consequently,the polarized electrolyte owns an unprecedented high-rate battery capacity of 114 mAh g^(-1)at~700 mA g^(-1)and also superior capacity performances with a cathode loading of 12 mg cm^(-2),outperforming the state-of-art PVH-based inorganic/organic composite electrolytes in Li||LiFePO_(4)battery.The work demonstrates an efficient strategy for achieving fast Liþdiffusion dynamics across polymeric matrices of classic solid-state electrolytes.展开更多
The design of heterostructured transition metal-based electrocatalysts with controlled composition and interfaces is key to increasing the efficiency of the water electrolysis and the elucidation of reaction mechanism...The design of heterostructured transition metal-based electrocatalysts with controlled composition and interfaces is key to increasing the efficiency of the water electrolysis and the elucidation of reaction mechanisms.In this work,we report the synthesis of well-controlled vertically aligned Ni/NiO nanocomposites consisting of Ni nanoclusters embedded in NiO,which result in highly efficient electrocatalysts for overall water splitting.We show that such a high catalytic efficiency toward both the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)originates from a synergetic effect at Ni/NiO interfaces that significantly reduces the energy barrier for water dissociation,and favours the formation of reactive H*intermediates on the Ni side of the interface,and OH_(ads) on the NiO side of the interface.A study of water chemisorption based on near-ambient pressure photoelectron spectroscopy indicates that the abundant hetero-interfaces in Ni/NiO nanocomposite promote the dissociation of water with a three-fold increase in the surface concentration of OH_(ads) compared with pure NiO.Density functional theory calculations indicate that Ni/NiO interface leads to the reduction of the water dissociation energy barrier due to a high concentration of oxygen vacancies at NiO side of the interface,whereas the formation of highly active metallic Ni sites with an optimal value of Gibbs free energy of H*(ΔG_(H*)=−0.16 eV)owes to a favourable adjustment of the electron energetics at the interface,thus accelerating the overall electrochemical water splitting.展开更多
基金supported by the National Natural Science Foundation of China(52225104 and 52071084)the Key Research and Development Program of Shanxi Province(2024CY2-GJHX-65)+1 种基金“Shuguang Program”supported by the Shanghai Education Development Foundation and Shanghai Municipal Education Commission(20SG03)Science and Technology Commission of Shanghai Municipality(22520710600)。
文摘The introduction of foreign metals with a higher oxophilicity represents a promising strategy to promote water dissociation and in turn kinetics of alkaline hydrogen evolution reaction(HER).However,the further improvement of HER activity is limited by the unfavorable interaction of hydroxyl generated by the dissociation of water with active sites.Herein,we propose a strategy of alkaline earth metal cations-driven electron delocalization to elaborately tailor the binding of hydroxyl with the active sites.Taking FeNiMg-layered double hydroxides(FeNiMg-LDH)as a prototypical example,the combined operando spectroscopy analysis and theoretical calculations show that the introduction of Mg cations in solid-solution phase can create a local electronic field and delocalize the electron between Fe and adsorbed hydroxyl,resulting in an optimization of hydroxyl binding strength.Accordingly,FeNiMg-LDH lowers the overpotentials to deliver 10 mA cm−2 in alkaline electrolyte by 39 and 64 mV,compared to FeNi-LDH and Ni-LDH catalysts,respectively.This work sheds new light on the rational design of advanced HER electrocatalyst for alkaline water electrolysis.
基金supported by Chongqing Technology Innovation and Application Development Special Key Project,CSTB2023TIAD-KPX0010Chongqing Technology Innovation and Application Development Special Major Project,CSTB2023TIAD-STX0033+1 种基金Natural Science Foundation of Chongqing,China(CSTB2022NSCQ-MSX0246,CSTB2022NSCQ-MSX1572,CSTB2022NSCQ-MSX0310)the Science Foundation of National Key Laboratory of Science and Technology on Advanced Composites in Special Environments.
文摘Solid-state lithium-metal batteries based on poly(vinylidene fluoride-co-hexafluoropropylene)(PVH)are frequently proposed to address the detrimental safety issue of conventional lithium-ion batteries by eliminating the use of flammable solvents,but still face a key challenge:low capacity and sluggish charge/discharge rate due to the intrinsic large-gradient Li^(+)distribution across the ionically-inert PVH matrix.Herein,Te vacancies in form of Bi_(2)Te_(3-x) are proposed to polarize the PVH unit to realize efficient decoupling of lithium salts at the atomic level in PVH-based solid polymeric electrolyte.Te vacancies in the PVH electrolyte doped with Bi_(2)Te_(3-x)(PVBT)induce a high-throughput and homogenous Li^(+)flow within the PVH matrices and near the Li metal.Theoretical calculations show that Te vacancies own high adsorption energy with bis(trifluoromethanesulfonyl)imide anions(TFSI^(-)),repulsive effect on Li^(+),and localized electron distribution,giving rise to a lithium-ion concentration gradient of 30 mol m^(-3),the smallest among the PVH-based inorganic/organic composite electrolytes.Consequently,the polarized electrolyte owns an unprecedented high-rate battery capacity of 114 mAh g^(-1)at~700 mA g^(-1)and also superior capacity performances with a cathode loading of 12 mg cm^(-2),outperforming the state-of-art PVH-based inorganic/organic composite electrolytes in Li||LiFePO_(4)battery.The work demonstrates an efficient strategy for achieving fast Liþdiffusion dynamics across polymeric matrices of classic solid-state electrolytes.
基金the National Natural Science Foundation of China(21872116)F.E.Oropeza and V.A.de la Peña O’Shea are grateful for the funding supported by the EU(ERC CoG HyMAP 648319)and Spanish AEI(NyMPhA PID2019-106315RB-I00)+3 种基金Also,this work has been funded by the regional government of Comunidad de Madrid and European Structural Funds through their financial support to FotoArt-CM project(S2018/NMT-4367)Besides,Fundación Ramon Areces funded this work though ArtLeaf project.Kelvin H.L.Zhang also acknowledge the Sino-German Mobility Program(M-0377)SuperSTEM is the National Research Facility for Advanced Electron Microscopy,funded from the Engineering and Physics Research Council(EPSRC)M.Bugnet is grateful to the SuperSTEM Laboratory for microscope access,and to the School of Chemical and Process Engineering at the University of Leeds for a visiting associate professorship and financial support.
文摘The design of heterostructured transition metal-based electrocatalysts with controlled composition and interfaces is key to increasing the efficiency of the water electrolysis and the elucidation of reaction mechanisms.In this work,we report the synthesis of well-controlled vertically aligned Ni/NiO nanocomposites consisting of Ni nanoclusters embedded in NiO,which result in highly efficient electrocatalysts for overall water splitting.We show that such a high catalytic efficiency toward both the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)originates from a synergetic effect at Ni/NiO interfaces that significantly reduces the energy barrier for water dissociation,and favours the formation of reactive H*intermediates on the Ni side of the interface,and OH_(ads) on the NiO side of the interface.A study of water chemisorption based on near-ambient pressure photoelectron spectroscopy indicates that the abundant hetero-interfaces in Ni/NiO nanocomposite promote the dissociation of water with a three-fold increase in the surface concentration of OH_(ads) compared with pure NiO.Density functional theory calculations indicate that Ni/NiO interface leads to the reduction of the water dissociation energy barrier due to a high concentration of oxygen vacancies at NiO side of the interface,whereas the formation of highly active metallic Ni sites with an optimal value of Gibbs free energy of H*(ΔG_(H*)=−0.16 eV)owes to a favourable adjustment of the electron energetics at the interface,thus accelerating the overall electrochemical water splitting.
