The microstructure,mechanical properties and stress corrosion cracking(SCC)of 7136 aluminum alloy under T 6,T 79 and T 74 aging treatments were studied and the effects of microstructure on the mechanical properties an...The microstructure,mechanical properties and stress corrosion cracking(SCC)of 7136 aluminum alloy under T 6,T 79 and T 74 aging treatments were studied and the effects of microstructure on the mechanical properties and SCC were discussed.The results show that the ultimate tensile strength and yield strength of the aging 7136 alloys follow this sequence from high to low:T 6>T 79>pre-aging>T 74.For 7136 Al alloy after T 6 aging,the average diameter of the precipitates was(5.7±1.7)nm,and the diameter of 60.7%(number fraction)precipitates was 2−6 nm,leading to a good precipitation strengthening.The K_(IC)of T 74-aging alloy is 38.2 MPa·m^(1/2),which is 26.1%more than that of T 6-aging alloy and 17.5%more than that of T 79-aging alloy.The improved fracture toughness in T 74-aging alloy is mainly due to the reduction of the strength difference between intragranular and grain boundary.The SCC resistance of the aging 7136 alloys follows this sequence from high to low:T 79>T 74>T 6.After T 79 aging,the discontinuous grain boundary precipitates and narrow precipitate free zones were obtained in 7136 alloy,which was beneficial to SCC resistance.展开更多
The Pb-free solders have attracted a great deal of attention recently due to the environmental concerns.The present work focuses on the effect of cobalt content(0,0.5 and 3.0)on the microstructural characteristics,mel...The Pb-free solders have attracted a great deal of attention recently due to the environmental concerns.The present work focuses on the effect of cobalt content(0,0.5 and 3.0)on the microstructural characteristics,melting point and corrosion performance of extruded Sn-9Zn solder alloys.The results reveal that the Zn-rich precipitates with spherical or needle-like shape in the Sn-9Zn-xCo alloys are refined remarkably by forming the γ-Co5Zn21 and Co2Sn2Zn Co-contained intermetallic compounds,though the melting point and eutectic reaction temperature decrease slightly.It is suggested that the corrosion property of the extruded Sn-9Zn-xCo alloys is improved significantly by adding the cobalt element,while the content should be controlled reasonably.Combining the corrosion morphology,the influence of cobalt content on the corrosion behavior of the Sn-9Zn-xCo alloys is analyzed in terms of the refined microstructure and the enhanced passive film stability.展开更多
Aqueous zinc metal batteries(AZMBs)have garnered widespread attention due to their low cost and high safety.However,current researches are still primarily focused on reversible cycling at low areal capacity,which is f...Aqueous zinc metal batteries(AZMBs)have garnered widespread attention due to their low cost and high safety.However,current researches are still primarily focused on reversible cycling at low areal capacity,which is far from practical application.Addressing interfacial stability issues encountered during cycling and employing interfacial optimization strategies can promote the development of safe and eco-friendly AZMBs.By introducingγ-valerolactone(GVL),which disrupts the original hydrogen bonding network of water,the electrochemical window of electrolyte is expanded,and the reactivity of water is significantly reduced.Additionally,the incorporation of GVL in Zn ion solvation alters the deposition pattern on the Zn anode surface,resulting in improved cyclic performance.The cells demonstrated excellent performance,maintaining stable over 400 h at 5 mA/cm^(2)-5 mA·h/cm^(2),and nearly 300 h in Zn||Zn symmetric cell at 80%depth of discharge(DOD).The full cells matched with NH_(4)V_(4)O_(10) could cycle over 200 cycles under the condition of high areal capacity(7 mA·h/cm^(2)),an N/P ratio of 1.99 and an E/C ratio of 9.3μL/(mA·h).展开更多
High-voltage sodium-ion batteries(SIBs)are emerging as promising candidates for large-scale energy storage systems due to their abundant sodium source and high energy density.However,the instability of the electrode e...High-voltage sodium-ion batteries(SIBs)are emerging as promising candidates for large-scale energy storage systems due to their abundant sodium source and high energy density.However,the instability of the electrode electrolyte interphase remains a critical barrier to the potential use of high-voltage SIBs.Herein,sodium difluorophosphate(NaDFP)and fluoroethylene carbonate(FEC)serve as functional electrolyte additives to stabilize the interface of the high-voltage cathode.The oxidative competition between FEC and NaDFP facilitates the robust formation of the cathode-electrolyte interface(CEI)layer,enriched with inorganic components such as NaF/NaPO_(x)F_(y).The highly conductive NaF/NaPO_(x)F_(y)and inorganics provide fast ion transport pathways and mechanical strength,thereby mitigating the decomposition of carbonates and NaPF_(6).The half-cell equipped with BE 2 F+0.5 DFP demonstrates 93.9%capacity retention at 4.3 V across 600 cycles,showcasing excellent cycling capability.Full HC||NVOPF cells exhibit sustained performance with 91.69%capacity retention and a capacity of 91.57 mA·h/g over 1000 cycles at a 5 C rate.This study is poised to garner increased scholarly interest in the domain of rational electrolyte formulation for practical applications.展开更多
Aqueous zinc-ion batteries(AZIBs)are promising energy storage systems because of their inherent safety and excellent sustainability.In this study,a zinc-chromium alloy layer is electrochemically deposited on the Zn an...Aqueous zinc-ion batteries(AZIBs)are promising energy storage systems because of their inherent safety and excellent sustainability.In this study,a zinc-chromium alloy layer is electrochemically deposited on the Zn anode(ZnCr@Zn)to enhance its performance in aqueous electrolytes.The ZnCr alloy layer can effectively modulate and homogenize Zn^(2+)flux,thus significantly promoting uniform Zn deposition.Meanwhile,the corrosion-resistant ZnCr alloy layer protects Zn from detrimental side reactions,improving Zn plating/stripping reversibility.Consequently,the ZnCr@Zn anode achieves a high average Coulombic efficiency of 99.9%at 2 mA/cm^(2)over 600 cycles.Furthermore,the ZnCr@Zn||NH_(4)V_(4)O_(10)coin cell reliably operates for over 2000 cycles at 2 A/g with a capacity retention rate of 88.7%.The ZnCr@Zn||NH_(4)V_(4)O_(10)pouch cell also demonstrates excellent stability over 160 cycles at a current density of 0.5 A/g.This work provides a facile approach to improve the Zn anode for high-performance AZIBs.展开更多
基金Project(2017GK2261)supported by the Science and Technology Program of Hunan Province,ChinaProject(41423040204)supported by National Key Laboratory of Light Weight and High Strength Structural Materials Equipment Pre-research Laboratory Foundation,China。
文摘The microstructure,mechanical properties and stress corrosion cracking(SCC)of 7136 aluminum alloy under T 6,T 79 and T 74 aging treatments were studied and the effects of microstructure on the mechanical properties and SCC were discussed.The results show that the ultimate tensile strength and yield strength of the aging 7136 alloys follow this sequence from high to low:T 6>T 79>pre-aging>T 74.For 7136 Al alloy after T 6 aging,the average diameter of the precipitates was(5.7±1.7)nm,and the diameter of 60.7%(number fraction)precipitates was 2−6 nm,leading to a good precipitation strengthening.The K_(IC)of T 74-aging alloy is 38.2 MPa·m^(1/2),which is 26.1%more than that of T 6-aging alloy and 17.5%more than that of T 79-aging alloy.The improved fracture toughness in T 74-aging alloy is mainly due to the reduction of the strength difference between intragranular and grain boundary.The SCC resistance of the aging 7136 alloys follows this sequence from high to low:T 79>T 74>T 6.After T 79 aging,the discontinuous grain boundary precipitates and narrow precipitate free zones were obtained in 7136 alloy,which was beneficial to SCC resistance.
基金Project(2017YFB0305700)supported by the Ministry of Science and Technology of ChinaProjects(51490660,51490664)supported by the National Natural Science Foundation of ChinaProject(2017YFB0305700)supported by the National Key Research and Development Project of China。
文摘The Pb-free solders have attracted a great deal of attention recently due to the environmental concerns.The present work focuses on the effect of cobalt content(0,0.5 and 3.0)on the microstructural characteristics,melting point and corrosion performance of extruded Sn-9Zn solder alloys.The results reveal that the Zn-rich precipitates with spherical or needle-like shape in the Sn-9Zn-xCo alloys are refined remarkably by forming the γ-Co5Zn21 and Co2Sn2Zn Co-contained intermetallic compounds,though the melting point and eutectic reaction temperature decrease slightly.It is suggested that the corrosion property of the extruded Sn-9Zn-xCo alloys is improved significantly by adding the cobalt element,while the content should be controlled reasonably.Combining the corrosion morphology,the influence of cobalt content on the corrosion behavior of the Sn-9Zn-xCo alloys is analyzed in terms of the refined microstructure and the enhanced passive film stability.
基金Project(2023YFC2908305)supported by the National Key R&D Program of ChinaProjects(52072411,52301273)supported by the National Natural Science Foundation of China+1 种基金Project(2023CXQD038)supported by the Central South University Innovation-Driven Research Program,ChinaProject(S202310533413)supported by the Fundamental Research Funds for the Central Universities of Central South University,China。
文摘Aqueous zinc metal batteries(AZMBs)have garnered widespread attention due to their low cost and high safety.However,current researches are still primarily focused on reversible cycling at low areal capacity,which is far from practical application.Addressing interfacial stability issues encountered during cycling and employing interfacial optimization strategies can promote the development of safe and eco-friendly AZMBs.By introducingγ-valerolactone(GVL),which disrupts the original hydrogen bonding network of water,the electrochemical window of electrolyte is expanded,and the reactivity of water is significantly reduced.Additionally,the incorporation of GVL in Zn ion solvation alters the deposition pattern on the Zn anode surface,resulting in improved cyclic performance.The cells demonstrated excellent performance,maintaining stable over 400 h at 5 mA/cm^(2)-5 mA·h/cm^(2),and nearly 300 h in Zn||Zn symmetric cell at 80%depth of discharge(DOD).The full cells matched with NH_(4)V_(4)O_(10) could cycle over 200 cycles under the condition of high areal capacity(7 mA·h/cm^(2)),an N/P ratio of 1.99 and an E/C ratio of 9.3μL/(mA·h).
基金Project(2023QNRC001)supported by the Young Elite Scientists Sponsorship Program by CAST,ChinaProject(51932011)supported by the National Natural Science Foundation of China+1 种基金Project(2023JJ10060)supported by the Natural Science Foundation of Hunan Province,ChinaProject(23A0003)supported by the Scientific Research Fund of Hunan Provincial Education Department,China。
文摘High-voltage sodium-ion batteries(SIBs)are emerging as promising candidates for large-scale energy storage systems due to their abundant sodium source and high energy density.However,the instability of the electrode electrolyte interphase remains a critical barrier to the potential use of high-voltage SIBs.Herein,sodium difluorophosphate(NaDFP)and fluoroethylene carbonate(FEC)serve as functional electrolyte additives to stabilize the interface of the high-voltage cathode.The oxidative competition between FEC and NaDFP facilitates the robust formation of the cathode-electrolyte interface(CEI)layer,enriched with inorganic components such as NaF/NaPO_(x)F_(y).The highly conductive NaF/NaPO_(x)F_(y)and inorganics provide fast ion transport pathways and mechanical strength,thereby mitigating the decomposition of carbonates and NaPF_(6).The half-cell equipped with BE 2 F+0.5 DFP demonstrates 93.9%capacity retention at 4.3 V across 600 cycles,showcasing excellent cycling capability.Full HC||NVOPF cells exhibit sustained performance with 91.69%capacity retention and a capacity of 91.57 mA·h/g over 1000 cycles at a 5 C rate.This study is poised to garner increased scholarly interest in the domain of rational electrolyte formulation for practical applications.
基金Projects(52172263,52372252)supported by the National Natural Science Foundation of ChinaProject(2024RC1022)supported by the Science and Technology Innovation Program of Hunan Province,China。
文摘Aqueous zinc-ion batteries(AZIBs)are promising energy storage systems because of their inherent safety and excellent sustainability.In this study,a zinc-chromium alloy layer is electrochemically deposited on the Zn anode(ZnCr@Zn)to enhance its performance in aqueous electrolytes.The ZnCr alloy layer can effectively modulate and homogenize Zn^(2+)flux,thus significantly promoting uniform Zn deposition.Meanwhile,the corrosion-resistant ZnCr alloy layer protects Zn from detrimental side reactions,improving Zn plating/stripping reversibility.Consequently,the ZnCr@Zn anode achieves a high average Coulombic efficiency of 99.9%at 2 mA/cm^(2)over 600 cycles.Furthermore,the ZnCr@Zn||NH_(4)V_(4)O_(10)coin cell reliably operates for over 2000 cycles at 2 A/g with a capacity retention rate of 88.7%.The ZnCr@Zn||NH_(4)V_(4)O_(10)pouch cell also demonstrates excellent stability over 160 cycles at a current density of 0.5 A/g.This work provides a facile approach to improve the Zn anode for high-performance AZIBs.
基金Projects(51774330, 52072411) supported by the National Natural Science Foundation of ChinaProject(2015) supported by the Teacher Research Foundation of Central South University,China+2 种基金Project(2022ZZTS0422) supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2021JJ20060) supported by the Natural Science Foundation of Hunan Province,ChinaProject(2021RC3001) supported by the Science and Technology Innovation Program of Hunan Province,China。
