α-MnO_(2) is a promising,inexpensive,and readily producible catalyst for the oxygen reduction reaction(ORR)in alkaline media,but its application is limited by low electronic conductivity.In this study,we enhance the ...α-MnO_(2) is a promising,inexpensive,and readily producible catalyst for the oxygen reduction reaction(ORR)in alkaline media,but its application is limited by low electronic conductivity.In this study,we enhance the performance ofα-MnO_(2) electrodes by systematically varying theα-MnO_(2)-to-Vulcan ratio within the catalyst layer.Electrodes are evaluated in a gas diffusion electrode(GDE)half-cell,where an optimized catalyst layer composition leads to significantly improved ORR performance.By finetuning both theα-MnO_(2)-to-Vulcan ratio and theα-MnO_(2) loading,the electrode outperforms a commercial MnO_(2)-based electrode and approaches the performance of the Pt/C benchmark.The improvement is attributed to the presence of a three-dimensional(3D)Vulcan network electronically connecting catalytically activeα-MnO_(2) sites with the substrate.Additionally,the optimized electrodes are employed in a prototype Al-O_(2) flow cell.Under constant oxygen flow,power densities exceed 250 mW cm^(-2),which is significantly higher than that of conventional Al-air batteries.Electrochemical impedance spectroscopy combined with distribution of relaxation times(DRT)analysis enables the separation of anode and cathode charge transfer impedances without the need for an additional reference electrode.The analysis reveals that the anode contributes more than twice as much impedance as the cathode,highlighting the need for further anode optimization.This work demonstrates a transferable approach for catalyst layer screening under technically relevant conditions in the GDE half-cell.Subsequent measurements in an Al-O_(2) flow cell validate the approach.The methodology is widely applicable to the development of advanced electrodes for a variety of metal-air battery technologies.展开更多
Ti-6Al-4Zr-2Sn-6Mo alloy is one of the most recent titanium alloys processed using powder bed fusion-laser beam(PBF-LB)technology.This alloy has the potential to replace Ti-6Al-4V in automotive and aerospace applicati...Ti-6Al-4Zr-2Sn-6Mo alloy is one of the most recent titanium alloys processed using powder bed fusion-laser beam(PBF-LB)technology.This alloy has the potential to replace Ti-6Al-4V in automotive and aerospace applications,given its superior mechanical properties,which are approximately 10%higher in terms of ultimate tensile strength(UTS)and yield strength after appropriate heat treatment.In as-built conditions,the alloy is characterized by the presence of soft orthorhombicα″martensite,necessitating a postprocessing heat treatment to decompose this phase and enhance the mechanical properties of the alloy.Usually,PBFed Ti6246 components undergo an annealing process that transforms theα″martensite into anα-βlamellar microstructure.The primary objective of this research was to develop a solution treatment and aging(STA)heat treatment tailored to the unique microstructure produced by the additive manufacturing process to achieve an ultrafine bilamellar microstructure reinforced by precipitation hardening.This study investigated the effects of various solution temperatures in theα-βfield(ranging from 800 to 875℃),cooling media(air and water),and aging time to determine the optimal heat treatment parameters for achieving the desired bilamellar microstructure.For each heat treatment condition,differentα-βmicrostructures were found,varying in terms of theα/βratio and the size of the primaryα-phase lamellae.Particular attention was given to how these factors were influenced by increases in solution temperature and how microhardness correlated with the percentage of the metastableβphase present after quenching.Tensile tests were performed on samples subjected to the most promising heat treatment parameters.A comparison with literature data revealed that the optimized STA treatment enhanced hardness and UTS by13%and 23%,respectively,compared with those of the annealed alloy.Fracture surface analyses were conducted to investigate fracture mechanisms.展开更多
本文基于近岸海洋数值模式ADCIRC(a parallel advanced circulation model for oceanic,coastal and estuarine waters)和近海波浪数值模式SWAN(simulating waves nearshore),建立了适用于文昌市的高分辨率风暴潮-海浪耦合漫滩模型,并以...本文基于近岸海洋数值模式ADCIRC(a parallel advanced circulation model for oceanic,coastal and estuarine waters)和近海波浪数值模式SWAN(simulating waves nearshore),建立了适用于文昌市的高分辨率风暴潮-海浪耦合漫滩模型,并以1415“海鸥”路径为基础,构建了覆盖文昌市岸段的台风路径集,对登陆位置进行敏感性分析,结果表明,在相同台风参数下,登陆位置对文昌市沿岸的增水幅度有明显影响。通过构建不同台风强度路径集,对比分析了不同台风强度下文昌市的风暴潮淹没情况,开展危险性分析。结果显示台风强度越强,引起的风暴潮淹没范围越大,淹没水深越深,高危险性面积越大。随着台风强度的降低,淹没范围逐渐减小,但由于八门湾、铺前湾地势较低,河道、滩涂较多,在990 hPa的强度下仍出现超过1.2 m的淹没水深,为易受灾区域,需要多加关注和防范。展开更多
In the quest for the development of safer lithium-metal batteries(LMBs),the integration of inorganic fillers and ionic liquids into polymer matrices has emerged as a promising strategy to enhance safety,ionic conducti...In the quest for the development of safer lithium-metal batteries(LMBs),the integration of inorganic fillers and ionic liquids into polymer matrices has emerged as a promising strategy to enhance safety,ionic conductivity and battery performance.This study introduces a novel composite ionogel(IG)synthesized through a facile one-pot method,incorporating butyl methacrylate(BMA)and poly(ethylene glycol)diacrylate(PEGDA)with the ionic liquid 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide(PYR_(14)FSI)and garnet Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)nanoparticles.A distinctive feature of the approach is the use of an organosilane functionalization of the LLZTO nanoparticles,which ensures their full integration into the polymer matrix during free-radical polymerization.Moreover,this method effectively eliminates the Li_(2)CO_(3)passivation layer that typically forms on the surface of the LLZTO nanoparticles,thus,further contributing to an enhanced performance.As a result,a LMB with the functionalized LLZTO IG electrolyte delivered more than 160 mA h g^(−1)with a very good capacity retention of 97.7%after 400 cycles in Li|IG|LFP cells.展开更多
基金part of the ALU-STORE project(Aluminum Metal as Energy Carrier for Seasonal Energy Storage)funded by the KIT Future Fieldsthe research performed at CELEST(Center for Electrochemical Energy Storage Ulm-Karlsruhe)+1 种基金funding from the German Federal Ministry of Research,Technology and Space(BMFTR)in the Nano Mat Futur program(03XP0423)basic funding from the Helmholtz Association。
文摘α-MnO_(2) is a promising,inexpensive,and readily producible catalyst for the oxygen reduction reaction(ORR)in alkaline media,but its application is limited by low electronic conductivity.In this study,we enhance the performance ofα-MnO_(2) electrodes by systematically varying theα-MnO_(2)-to-Vulcan ratio within the catalyst layer.Electrodes are evaluated in a gas diffusion electrode(GDE)half-cell,where an optimized catalyst layer composition leads to significantly improved ORR performance.By finetuning both theα-MnO_(2)-to-Vulcan ratio and theα-MnO_(2) loading,the electrode outperforms a commercial MnO_(2)-based electrode and approaches the performance of the Pt/C benchmark.The improvement is attributed to the presence of a three-dimensional(3D)Vulcan network electronically connecting catalytically activeα-MnO_(2) sites with the substrate.Additionally,the optimized electrodes are employed in a prototype Al-O_(2) flow cell.Under constant oxygen flow,power densities exceed 250 mW cm^(-2),which is significantly higher than that of conventional Al-air batteries.Electrochemical impedance spectroscopy combined with distribution of relaxation times(DRT)analysis enables the separation of anode and cathode charge transfer impedances without the need for an additional reference electrode.The analysis reveals that the anode contributes more than twice as much impedance as the cathode,highlighting the need for further anode optimization.This work demonstrates a transferable approach for catalyst layer screening under technically relevant conditions in the GDE half-cell.Subsequent measurements in an Al-O_(2) flow cell validate the approach.The methodology is widely applicable to the development of advanced electrodes for a variety of metal-air battery technologies.
基金financed by the European Union-Next Generation EU(National Sustainable Mobility Center CN00000023,Italian Ministry of University and Research Decree n.1033-17/06/2022,Spoke 11-Innovative Materials&Lightweighting)。
文摘Ti-6Al-4Zr-2Sn-6Mo alloy is one of the most recent titanium alloys processed using powder bed fusion-laser beam(PBF-LB)technology.This alloy has the potential to replace Ti-6Al-4V in automotive and aerospace applications,given its superior mechanical properties,which are approximately 10%higher in terms of ultimate tensile strength(UTS)and yield strength after appropriate heat treatment.In as-built conditions,the alloy is characterized by the presence of soft orthorhombicα″martensite,necessitating a postprocessing heat treatment to decompose this phase and enhance the mechanical properties of the alloy.Usually,PBFed Ti6246 components undergo an annealing process that transforms theα″martensite into anα-βlamellar microstructure.The primary objective of this research was to develop a solution treatment and aging(STA)heat treatment tailored to the unique microstructure produced by the additive manufacturing process to achieve an ultrafine bilamellar microstructure reinforced by precipitation hardening.This study investigated the effects of various solution temperatures in theα-βfield(ranging from 800 to 875℃),cooling media(air and water),and aging time to determine the optimal heat treatment parameters for achieving the desired bilamellar microstructure.For each heat treatment condition,differentα-βmicrostructures were found,varying in terms of theα/βratio and the size of the primaryα-phase lamellae.Particular attention was given to how these factors were influenced by increases in solution temperature and how microhardness correlated with the percentage of the metastableβphase present after quenching.Tensile tests were performed on samples subjected to the most promising heat treatment parameters.A comparison with literature data revealed that the optimized STA treatment enhanced hardness and UTS by13%and 23%,respectively,compared with those of the annealed alloy.Fracture surface analyses were conducted to investigate fracture mechanisms.
文摘本文基于近岸海洋数值模式ADCIRC(a parallel advanced circulation model for oceanic,coastal and estuarine waters)和近海波浪数值模式SWAN(simulating waves nearshore),建立了适用于文昌市的高分辨率风暴潮-海浪耦合漫滩模型,并以1415“海鸥”路径为基础,构建了覆盖文昌市岸段的台风路径集,对登陆位置进行敏感性分析,结果表明,在相同台风参数下,登陆位置对文昌市沿岸的增水幅度有明显影响。通过构建不同台风强度路径集,对比分析了不同台风强度下文昌市的风暴潮淹没情况,开展危险性分析。结果显示台风强度越强,引起的风暴潮淹没范围越大,淹没水深越深,高危险性面积越大。随着台风强度的降低,淹没范围逐渐减小,但由于八门湾、铺前湾地势较低,河道、滩涂较多,在990 hPa的强度下仍出现超过1.2 m的淹没水深,为易受灾区域,需要多加关注和防范。
基金the German Federal Ministry for Education and Research(BMBF)for financial support within the FB2-Hybrid project(03XP0428B)Moreover,D.Bresser and T.Diemant would like to acknowledge financial support from the Helmholtz Association.
文摘In the quest for the development of safer lithium-metal batteries(LMBs),the integration of inorganic fillers and ionic liquids into polymer matrices has emerged as a promising strategy to enhance safety,ionic conductivity and battery performance.This study introduces a novel composite ionogel(IG)synthesized through a facile one-pot method,incorporating butyl methacrylate(BMA)and poly(ethylene glycol)diacrylate(PEGDA)with the ionic liquid 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide(PYR_(14)FSI)and garnet Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)nanoparticles.A distinctive feature of the approach is the use of an organosilane functionalization of the LLZTO nanoparticles,which ensures their full integration into the polymer matrix during free-radical polymerization.Moreover,this method effectively eliminates the Li_(2)CO_(3)passivation layer that typically forms on the surface of the LLZTO nanoparticles,thus,further contributing to an enhanced performance.As a result,a LMB with the functionalized LLZTO IG electrolyte delivered more than 160 mA h g^(−1)with a very good capacity retention of 97.7%after 400 cycles in Li|IG|LFP cells.
