Tin (Sn) metal foil is a promising anode for next-generation high-energy–density lithium-ion batteries (LIBs) due to its high capacity and easy processibility. However, the pristine Sn foil anode suffers nonuniform a...Tin (Sn) metal foil is a promising anode for next-generation high-energy–density lithium-ion batteries (LIBs) due to its high capacity and easy processibility. However, the pristine Sn foil anode suffers nonuniform alloying/dealloying reaction with lithium (Li) and huge volume variation, leading to electrode pulverization and inferior electrochemical performance. Herein, we proposed that reduced grain size and elaborate porosity design of Sn foil can circumvent the nonuniform alloy reaction and buffer the volume change during the lithiation/delithiation cycling. Experimentally, we designed a three-dimensional interconnected porous Sn (3DIP-Sn) foil by a facile chemical alloying/dealloying approach, which showed improved electrochemical performance. The enhanced structure stability of the as-fabricated 3DIP-Sn foil was verified by chemo-mechanical simulations and experimental investigation. As expected, the 3DIP-Sn foil anode revealed a long cycle lifespan of 4400 h at 0.5 mA cm^(−2) and 1 mAh cm^(−2) in Sn||Li half cells. A 3DIP-Sn||LiFePO_(4) full cell with LiFePO_(4) loading of 7.1 mg cm^(−2) exhibited stable cycling for 500 cycles with 80% capacity retention at 70 mA g^(−1). Pairing with high-loading commercial LiNi0.6Co0.2Mn0.2O_(2) (NCM622, 18.4 mg cm^(−2)) cathode, a 3DIP-Sn||NCM622 full cell delivered a high reversible capacity of 3.2 mAh cm^(−2). These results demonstrated the important role of regulating the uniform alloying/dealloying reaction and circumventing the localized strain/stress in improving the electrochemical performance of Sn foil anodes for advanced LIBs.展开更多
Aqueous rechargeable magnesium ion batteries(ARMBs) have obtained more attention due to the twoelectrons transfer nature, low cost and safety. However, the scarcity of cathode materials seriously hinders the developme...Aqueous rechargeable magnesium ion batteries(ARMBs) have obtained more attention due to the twoelectrons transfer nature, low cost and safety. However, the scarcity of cathode materials seriously hinders the development of ARMBs because of the unfavorable strong interaction between Mg^(2+) and cathode material. Herein, we choose a pre-treated spinel Mn_(3)O_(4) cathode for aqueous Mg^(2+) storage. The pretreatment in Na_(2)SO_(4) solution induces the grain refinement decorated with tortuous amorphous ion diffusion channels, facilitating the production of electrochemical reaction active sites and the diffusion of Mg^(2+), respectively, which achieve a(sub-)surface pseudocapacitance reaction between Mn(Ⅱ) and Mn(Ⅲ). As a result, the pre-treated Mn_(3)O_(4) cathode exhibits a package of optimal performances, i.e., a capacity of 98.9 m Ah g^(-1) and a high capacity retention rate of 99.4% after 2000 cycles. To the best of our knowledge, our work not only provides a new reaction mechanism of spinelMn_(3)O_(4) in aqueous batteries system,but also affords a high cycle stability electrode material for rechargeable Mg^(2+) energy storage.展开更多
Fine-grained Nd10.79Pr2.8Al0.4B7.72Fe78.29 magnets were prepared by low temperature pre-sintering and subsequent hot pressing. The grain size of the magnets is just about 1–3 μm because the low sintering temperature...Fine-grained Nd10.79Pr2.8Al0.4B7.72Fe78.29 magnets were prepared by low temperature pre-sintering and subsequent hot pressing. The grain size of the magnets is just about 1–3 μm because the low sintering temperature results in no grain growth. The orientation degree, microstructure, and magnetic properties were studied. Some grains＇ easy axes deviate from the orientation direction, possibly due to grain rotation during the hot pressing. By subsequent annealing, the magnetic properties were significantly enhanced. Especially, the squareness of the demagnetization curve was improved greatly.The enhancement of coercivity by annealing can be explained by an improvement of both grain boundaries and magnetic isolation, which decouples the exchange interaction between neighboring grains.展开更多
Failure may occur catastrophically by fracture along grain boundaries when temper embrittlement induced by non-equilibrium grain-boundary segregation (NGS) of phosphorus atoms. Temper embrittlement control technigue b...Failure may occur catastrophically by fracture along grain boundaries when temper embrittlement induced by non-equilibrium grain-boundary segregation (NGS) of phosphorus atoms. Temper embrittlement control technigue based on the theory of NGS and deformation induced phase transformation method was studied in this paper. Grain refinement technique by deformation induced phase transformation in low-alloy steel,12Cr1MoV( which is used in steam pipeline of ships),was experimentally investigated. A single-pass hot rolling process by using a Gleeble-1500 system was performed and the experimental results showed that the grain sizes were obviously affected by the deforming temperature,strain,strain rate and the quenching cooling rate. Temper embrittlement may be controlled and obviously improved by grain refinement.展开更多
To investigate the coercivity,corrosion resistance,and thermal stability of Nd-Fe-B magnets,their properties were investigated at room and high temperature before and after doping with Dy（80）Ga（20）（at.%） powder....To investigate the coercivity,corrosion resistance,and thermal stability of Nd-Fe-B magnets,their properties were investigated at room and high temperature before and after doping with Dy（80）Ga（20）（at.%） powder.The coercivity of the magnets increased from the undoped value of 12.72 kOe to a doped value of 21.44 kOe.A micro-structural analysis indicates that a well-developed core-shell structure forms in the magnets doped with Dy（80）Ga（20） powder.The improvement in magnetic properties is believed to be related to the refined and uniform matrix grains,continuous grain boundaries,and a hardened（Nd,Dy）2Fe（14）B shell surrounding the matrix grains.Additionally,the doped magnets exhibit an obvious improvement in thermal stability.For the magnets with added Dy（80）Ga（20） powder,the temperature coefficients of remanence（α） and coercivity（β） increased to-0.106%℃-（-1） and-0.60%℃-（-1） over the range 20-100 ℃,compared to temperature coefficients of-0.117%℃-（-1）（α） and-0.74%℃-（-1）（β） in the regular magnets without Dy（80）Ga（20） powder.The irreversible loss of magnetic flux（Hirr） was investigated at different temperatures.After being exposed to 150 ℃ for 2 h,the Hirr of magnets with 4 wt.%Dy（80）Ga（20） decreased by -95%compared to that of the undoped magnets.The enhanced temperature coefficients and Hirr indicate improved thermal stability in the doped Nd-Fe-B magnets.The intergranular addition of Dy（80）Ga（20） also improved the corrosion resistance of the magnets because of the enhanced intergranular phase.In a corrosive atmosphere for 96 h,the mass loss of the sintered magnets with 4 wt.%Dy（80）Ga（20） was 2.68 mg/cm-2,less than 10%of that suffered by the undoped magnets（28.1 mg/cm-2）.展开更多
Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials...Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials science,decreasing the grain size introduces more grain boundaries;this stops dislocations and crack propagation under deformation,and results in increased strength and toughness.However,such a size refinement effect has not been considered in the mechanical properties,particle stacking,wetting,and electrochemical performances of flexible supercapacitor electrodes.In this paper,MXene was used as an electrode material to study the size refinement effect of flexible supercapacitors.Size refinement improved the strength and toughness of the MXene electrodes,and this resulted in increased flexibility.Finite elemental analysis provided a theoretical understanding of size refinement-increased flexibility.Moreover,the size refinement also improved the specific surface area,electric conductance,ion transportation,and water wetting properties of the electrode,and the size refinement provided highly increased energy density and power density of the MXene supercapacitors.A highly flexible,water-proof supercapacitor was fabricated using size-refined MXene.The current study provides a new viewpoint for designing tough and flexible energy storage electrodes.The size refinement effect may also be applicable for metal ion batteries and electronic and photo devices composed of MXene and other nanoparticles.展开更多
基金This work is financially supported by the National Natural Science Foundation of China(Grant Nos.52072137,51802105).
文摘Tin (Sn) metal foil is a promising anode for next-generation high-energy–density lithium-ion batteries (LIBs) due to its high capacity and easy processibility. However, the pristine Sn foil anode suffers nonuniform alloying/dealloying reaction with lithium (Li) and huge volume variation, leading to electrode pulverization and inferior electrochemical performance. Herein, we proposed that reduced grain size and elaborate porosity design of Sn foil can circumvent the nonuniform alloy reaction and buffer the volume change during the lithiation/delithiation cycling. Experimentally, we designed a three-dimensional interconnected porous Sn (3DIP-Sn) foil by a facile chemical alloying/dealloying approach, which showed improved electrochemical performance. The enhanced structure stability of the as-fabricated 3DIP-Sn foil was verified by chemo-mechanical simulations and experimental investigation. As expected, the 3DIP-Sn foil anode revealed a long cycle lifespan of 4400 h at 0.5 mA cm^(−2) and 1 mAh cm^(−2) in Sn||Li half cells. A 3DIP-Sn||LiFePO_(4) full cell with LiFePO_(4) loading of 7.1 mg cm^(−2) exhibited stable cycling for 500 cycles with 80% capacity retention at 70 mA g^(−1). Pairing with high-loading commercial LiNi0.6Co0.2Mn0.2O_(2) (NCM622, 18.4 mg cm^(−2)) cathode, a 3DIP-Sn||NCM622 full cell delivered a high reversible capacity of 3.2 mAh cm^(−2). These results demonstrated the important role of regulating the uniform alloying/dealloying reaction and circumventing the localized strain/stress in improving the electrochemical performance of Sn foil anodes for advanced LIBs.
基金supported by the National Natural Science Foundation of China (51932003, 51872115)the 2020 International Cooperation Project of the Department of Science and Technology of Jilin Province (20200801001GH)+4 种基金the Program for the Development of Science and Technology of Jilin Province(20190201309JC)the Jilin Province/Jilin University coConstruction Project-Funds for New Materials (SXGJSF2017-3,Branch-2/440050316A36)the Project for Self-innovation Capability Construction of Jilin Province Development and Reform Commission (2021C026)the Program for JLU Science and Technology Innovative Research Team (JLUSTIRT, 2017TD-09)the Fundamental Research Funds for the Central Universities JLU, and “DoubleFirst Class” Discipline for Materials Science&Engineering。
文摘Aqueous rechargeable magnesium ion batteries(ARMBs) have obtained more attention due to the twoelectrons transfer nature, low cost and safety. However, the scarcity of cathode materials seriously hinders the development of ARMBs because of the unfavorable strong interaction between Mg^(2+) and cathode material. Herein, we choose a pre-treated spinel Mn_(3)O_(4) cathode for aqueous Mg^(2+) storage. The pretreatment in Na_(2)SO_(4) solution induces the grain refinement decorated with tortuous amorphous ion diffusion channels, facilitating the production of electrochemical reaction active sites and the diffusion of Mg^(2+), respectively, which achieve a(sub-)surface pseudocapacitance reaction between Mn(Ⅱ) and Mn(Ⅲ). As a result, the pre-treated Mn_(3)O_(4) cathode exhibits a package of optimal performances, i.e., a capacity of 98.9 m Ah g^(-1) and a high capacity retention rate of 99.4% after 2000 cycles. To the best of our knowledge, our work not only provides a new reaction mechanism of spinelMn_(3)O_(4) in aqueous batteries system,but also affords a high cycle stability electrode material for rechargeable Mg^(2+) energy storage.
基金Project supported by the National Natural Science Foundation of China(Grant No.51101167)the National Science and Technology Major Project,China(Grant No.2012ZX02702006-005)+2 种基金the Local Cooperation Project of Chinese Academy of Sciences(Grant No.DBSH-2011-013)the Natural Science Foundation of Zhejiang Province,China(Grant No.LQ14E010007)the Natural Science Foundation of Ningbo,China(Grant No.2014A610161)
文摘Fine-grained Nd10.79Pr2.8Al0.4B7.72Fe78.29 magnets were prepared by low temperature pre-sintering and subsequent hot pressing. The grain size of the magnets is just about 1–3 μm because the low sintering temperature results in no grain growth. The orientation degree, microstructure, and magnetic properties were studied. Some grains＇ easy axes deviate from the orientation direction, possibly due to grain rotation during the hot pressing. By subsequent annealing, the magnetic properties were significantly enhanced. Especially, the squareness of the demagnetization curve was improved greatly.The enhancement of coercivity by annealing can be explained by an improvement of both grain boundaries and magnetic isolation, which decouples the exchange interaction between neighboring grains.
文摘Failure may occur catastrophically by fracture along grain boundaries when temper embrittlement induced by non-equilibrium grain-boundary segregation (NGS) of phosphorus atoms. Temper embrittlement control technigue based on the theory of NGS and deformation induced phase transformation method was studied in this paper. Grain refinement technique by deformation induced phase transformation in low-alloy steel,12Cr1MoV( which is used in steam pipeline of ships),was experimentally investigated. A single-pass hot rolling process by using a Gleeble-1500 system was performed and the experimental results showed that the grain sizes were obviously affected by the deforming temperature,strain,strain rate and the quenching cooling rate. Temper embrittlement may be controlled and obviously improved by grain refinement.
基金Project supported by the Ministry of Science and Technology of China(Grant Nos.2014DFB50130 and 2011CB612304)the National Natural Science Foundation of China(Grant Nos.51172168 and 51072139)
文摘To investigate the coercivity,corrosion resistance,and thermal stability of Nd-Fe-B magnets,their properties were investigated at room and high temperature before and after doping with Dy（80）Ga（20）（at.%） powder.The coercivity of the magnets increased from the undoped value of 12.72 kOe to a doped value of 21.44 kOe.A micro-structural analysis indicates that a well-developed core-shell structure forms in the magnets doped with Dy（80）Ga（20） powder.The improvement in magnetic properties is believed to be related to the refined and uniform matrix grains,continuous grain boundaries,and a hardened（Nd,Dy）2Fe（14）B shell surrounding the matrix grains.Additionally,the doped magnets exhibit an obvious improvement in thermal stability.For the magnets with added Dy（80）Ga（20） powder,the temperature coefficients of remanence（α） and coercivity（β） increased to-0.106%℃-（-1） and-0.60%℃-（-1） over the range 20-100 ℃,compared to temperature coefficients of-0.117%℃-（-1）（α） and-0.74%℃-（-1）（β） in the regular magnets without Dy（80）Ga（20） powder.The irreversible loss of magnetic flux（Hirr） was investigated at different temperatures.After being exposed to 150 ℃ for 2 h,the Hirr of magnets with 4 wt.%Dy（80）Ga（20） decreased by -95%compared to that of the undoped magnets.The enhanced temperature coefficients and Hirr indicate improved thermal stability in the doped Nd-Fe-B magnets.The intergranular addition of Dy（80）Ga（20） also improved the corrosion resistance of the magnets because of the enhanced intergranular phase.In a corrosive atmosphere for 96 h,the mass loss of the sintered magnets with 4 wt.%Dy（80）Ga（20） was 2.68 mg/cm-2,less than 10%of that suffered by the undoped magnets（28.1 mg/cm-2）.
基金supported by the National Key Research and Development Program of China(grant SQ2019YFE012189,grant2017YFB0307001)the National Natural Science Foundation of China(grants 51973093,U1533122,and 51773094)+5 种基金the Natural Science Foundation of Tianjin(grant number 18JCZDJC36800)the National Special Support Plan for High-level Talents people(grant number C041800902)the Science Foundation for Distinguished Young Scholars of Tianjin(grant number 18JCJQJC46600)the Frontiers Science Center for New Organic Matter(Grant Number 63181206)the Fundamental Research Funds for the Central Universities(grant 63171219)the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(grant LK1704)。
文摘Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials science,decreasing the grain size introduces more grain boundaries;this stops dislocations and crack propagation under deformation,and results in increased strength and toughness.However,such a size refinement effect has not been considered in the mechanical properties,particle stacking,wetting,and electrochemical performances of flexible supercapacitor electrodes.In this paper,MXene was used as an electrode material to study the size refinement effect of flexible supercapacitors.Size refinement improved the strength and toughness of the MXene electrodes,and this resulted in increased flexibility.Finite elemental analysis provided a theoretical understanding of size refinement-increased flexibility.Moreover,the size refinement also improved the specific surface area,electric conductance,ion transportation,and water wetting properties of the electrode,and the size refinement provided highly increased energy density and power density of the MXene supercapacitors.A highly flexible,water-proof supercapacitor was fabricated using size-refined MXene.The current study provides a new viewpoint for designing tough and flexible energy storage electrodes.The size refinement effect may also be applicable for metal ion batteries and electronic and photo devices composed of MXene and other nanoparticles.
