The pursuit of Ag-based alloys with both high strength and toughness has posed a longstanding chal-lenge.In this study,we investigated the cluster strengthening and grain refinement toughening mecha-nisms in fully oxi...The pursuit of Ag-based alloys with both high strength and toughness has posed a longstanding chal-lenge.In this study,we investigated the cluster strengthening and grain refinement toughening mecha-nisms in fully oxidized AgMgNi alloys,which were internally oxidized at 800℃ for 8 h under an oxy-gen atmosphere.We found that Mg-O clusters contributed to the hardening(138 HV)and strengthening(376.9 MPa)of the AgMg alloy through solid solution strengthening effects,albeit at the expense of duc-tility.To address this limitation,we introduced Ni nanoparticles into the AgMg alloy,resulting in signifi-cant grain refinement within its microstructure.Specifically,the grain size decreased from 67.2μm in the oxidized AgMg alloy to below 6.0μm in the oxidized AgMgNi alloy containing 0.3 wt%Ni.Consequently,the toughness increased significantly,rising from toughness value of 2177.9 MJ m^(-3) in the oxidized AgMg alloy to 6186.1 MJ m^(-3) in the oxidized AgMgNi alloy,representing a remarkable 2.8-fold enhancement.Furthermore,the internally oxidized AgMgNi alloy attained a strength of up to 387.6 MPa,comparable to that of the internally oxidized AgMg alloy,thereby demonstrating the successful realization of concurrent strengthening and toughening.These results collectively offer a novel approach for the design of high-performance alloys through the synergistic combination of cluster strengthening and grain refinement toughening.展开更多
High operating temperatures generally degrade the luminous performance of color converters used in high-power,laser-driven white lighting systems.This study demonstrated that the operating temperature of LuAG:Ce films...High operating temperatures generally degrade the luminous performance of color converters used in high-power,laser-driven white lighting systems.This study demonstrated that the operating temperature of LuAG:Ce films can be significantly reduced,particularly under high-power laser excitation near the saturation threshold.This improvement was achieved by enhancing the crystallinity and increasing the Ce^(3+)content in LuAG:Ce films.LuAG:Ce films,approximately 22.17μm in thickness,were deposited on sapphire substrates via spray pyrolysis techniques.The crystallinity was controlled by the annealing temperature,while the Ce^(3+)content was regulated by the annealing atmosphere.Compared with those with a crystallinity of 75.5%,the air-annealed films with a crystallinity of 87.4%exhibited a remarkable 95.6℃decrease in operating temperature under 18 W/mm^(2)blue laser excitation.Additionally,the incorporation of a higher Ce^(3+)content through CO annealing led to a further reduction in the operating temperature.By lowering the operating temperature,LuAG:Ce films on sapphire substrates exhibit enhanced luminous performance and thermal stability under prolonged high-power laser excitation,which could inspire the design and development of advanced color converters for laser lighting applications.展开更多
开发具有多层次结构(包括多孔结构、杂化骨架和/或拓扑形貌)的超结构碳材料,对于满足电化学储能和转换系统中复杂催化反应的需求非常关键.在本文中,我们以钴纳米颗粒为催化位点,在杂化碳纳米管骨架表面可控接枝毛发状碳纳米管,开发了一...开发具有多层次结构(包括多孔结构、杂化骨架和/或拓扑形貌)的超结构碳材料,对于满足电化学储能和转换系统中复杂催化反应的需求非常关键.在本文中,我们以钴纳米颗粒为催化位点,在杂化碳纳米管骨架表面可控接枝毛发状碳纳米管,开发了一类层次化多孔的钴修饰碳纳米管瓶刷(Co/CNTBs).其中,精确的瓶刷状拓扑形貌和分级多孔结构能够有效地提供可及表/界面和高导电网络,钴修饰的杂化骨架可以促进硫的氧化还原反应动力学.因此,基于Co/CNTBs功能化隔膜的锂硫电池具有优异的倍率性能(在10 C下比容量为707 mA h g^(-1))和长效的循环稳定性.更重要的是,基于Co/CNTBs催化剂的高硫载量电池(6.72 mg cm^(-2))在0.1 C下循环100圈后仍具有4.81 mA h cm^(-2)的高面积容量.本工作为高性能超结构杂化碳材料的原位接枝合成策略带来了新的思路,有望用于众多具有挑战性的应用.展开更多
基于固态电解质的高安全性和高能量密度锂金属电池有望成为下一代储能器件.然而,固态电解质在高离子电导率与优良机械性能之间难以兼得,严重阻碍了其实际应用.本文利用多孔高分子刷(刚性多孔超交联聚氯甲基苯乙烯纳米球(xPCMS)表面接枝...基于固态电解质的高安全性和高能量密度锂金属电池有望成为下一代储能器件.然而,固态电解质在高离子电导率与优良机械性能之间难以兼得,严重阻碍了其实际应用.本文利用多孔高分子刷(刚性多孔超交联聚氯甲基苯乙烯纳米球(xPCMS)表面接枝聚甲基丙烯酸缩水甘油酯(PGMA),xPCMS-g-PGMA)作为纳米填料,将其与聚乙二醇二胺(DPEG)、聚乙二醇二缩水甘油醚(PEGDE)进行交联,并引入电解液塑化剂后成功获得了一类坚韧的全有机复合电解质(xPCMS-g-PGMA-AOCE).刚性多孔xPCMS骨架可以增强复合膜的机械强度并为锂离子传输提供充足通道;毛发状反应性PGMA侧链有利于xPCMS-g-PGMA与DPEG、PEGDE等锂离子传输连续相之间形成均匀的三维交联网络结构,可以进一步提高膜力学性能以及促进锂离子均匀、快速传输.因此,基于xPCMS-g-PGMA-AOCE组装的锂金属电池在1 C电流密度下首圈放电比容量高达155 mAh g^(-1),循环360圈后容量保持率为88%.展开更多
Lithium-sulfur(Li-S)batteries have been regarded as promising next-generation energy-storage devices owing to their inherently high theoretical energy density.Unfortunately,the poor capacity and cycling life caused by...Lithium-sulfur(Li-S)batteries have been regarded as promising next-generation energy-storage devices owing to their inherently high theoretical energy density.Unfortunately,the poor capacity and cycling life caused by severe polysulfide shuttle effect and sluggish redox kinetics in sulfur cathodes greatly impede the practical application of Li-S batteries.Herein,a new class of nanonetworkstructured carbon decorated with oxygen-vacancy-containing cerium oxide nanoparticles(NSC-CeO_(2−x)),in which carbon skeleton is composed of highly conductive carbon nanotube core welded by hybrid carbon shell,has been developed via one-step heating treatment of hybrid molecular brush and further employed as functional interlayer to modify separator of Li-S battery.Owing to the synergistic effect of the highly active CeO_(2−x)nanoparticles and the threedimensional carbon nanonetwork in enhancing the preservation of the soluble polysulfides and boosting the redox kinetics of sulfur species,the NSC-CeO_(2−x)significantly promotes the electrochemical performance of sulfur cathode.As a result,the as-constructed Li-S batteries exhibit an ultrahigh initial sulfur utilization of 92.9%and an extremely large capacity of 751mA h g^(−1) at a high rate of 5 C.Remarkably,a stable capacity of 728 mA h g^(−1)over 300 cycles at 1 C is also achieved.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51977027 and 51967008)the Scientific and Technological Project of Yunnan Precious Metals Lab-oratory(Nos.YPML-2023050250 and YPML-2022050206).
文摘The pursuit of Ag-based alloys with both high strength and toughness has posed a longstanding chal-lenge.In this study,we investigated the cluster strengthening and grain refinement toughening mecha-nisms in fully oxidized AgMgNi alloys,which were internally oxidized at 800℃ for 8 h under an oxy-gen atmosphere.We found that Mg-O clusters contributed to the hardening(138 HV)and strengthening(376.9 MPa)of the AgMg alloy through solid solution strengthening effects,albeit at the expense of duc-tility.To address this limitation,we introduced Ni nanoparticles into the AgMg alloy,resulting in signifi-cant grain refinement within its microstructure.Specifically,the grain size decreased from 67.2μm in the oxidized AgMg alloy to below 6.0μm in the oxidized AgMgNi alloy containing 0.3 wt%Ni.Consequently,the toughness increased significantly,rising from toughness value of 2177.9 MJ m^(-3) in the oxidized AgMg alloy to 6186.1 MJ m^(-3) in the oxidized AgMgNi alloy,representing a remarkable 2.8-fold enhancement.Furthermore,the internally oxidized AgMgNi alloy attained a strength of up to 387.6 MPa,comparable to that of the internally oxidized AgMg alloy,thereby demonstrating the successful realization of concurrent strengthening and toughening.These results collectively offer a novel approach for the design of high-performance alloys through the synergistic combination of cluster strengthening and grain refinement toughening.
基金supported by the National Natural Science Foundation of China(Nos.51977027 and 51967008)the Scientific and Technological Project of Yunnan Precious Metals Laboratory(Nos.YPML-2023050250,YPML-2022050206,YPML20240502061,YPML-20240502062,and YPML-20240502091).
文摘High operating temperatures generally degrade the luminous performance of color converters used in high-power,laser-driven white lighting systems.This study demonstrated that the operating temperature of LuAG:Ce films can be significantly reduced,particularly under high-power laser excitation near the saturation threshold.This improvement was achieved by enhancing the crystallinity and increasing the Ce^(3+)content in LuAG:Ce films.LuAG:Ce films,approximately 22.17μm in thickness,were deposited on sapphire substrates via spray pyrolysis techniques.The crystallinity was controlled by the annealing temperature,while the Ce^(3+)content was regulated by the annealing atmosphere.Compared with those with a crystallinity of 75.5%,the air-annealed films with a crystallinity of 87.4%exhibited a remarkable 95.6℃decrease in operating temperature under 18 W/mm^(2)blue laser excitation.Additionally,the incorporation of a higher Ce^(3+)content through CO annealing led to a further reduction in the operating temperature.By lowering the operating temperature,LuAG:Ce films on sapphire substrates exhibit enhanced luminous performance and thermal stability under prolonged high-power laser excitation,which could inspire the design and development of advanced color converters for laser lighting applications.
基金supported by the National Natural Science Foundation of China(51872336,51925308,and 52172061)the National Key Research and Development Program of China(2021YFF0500600)+3 种基金the Pearl River Talent Plan of Guangdong(2017GC010612)the Natural Science Foundation of Guangdong(2021A1515011617)the Fundamental Research Funds for the Central Universities(20lgzd18)the Science and Technology Program of Guangzhou(202102021111 and 202002020041)。
文摘开发具有多层次结构(包括多孔结构、杂化骨架和/或拓扑形貌)的超结构碳材料,对于满足电化学储能和转换系统中复杂催化反应的需求非常关键.在本文中,我们以钴纳米颗粒为催化位点,在杂化碳纳米管骨架表面可控接枝毛发状碳纳米管,开发了一类层次化多孔的钴修饰碳纳米管瓶刷(Co/CNTBs).其中,精确的瓶刷状拓扑形貌和分级多孔结构能够有效地提供可及表/界面和高导电网络,钴修饰的杂化骨架可以促进硫的氧化还原反应动力学.因此,基于Co/CNTBs功能化隔膜的锂硫电池具有优异的倍率性能(在10 C下比容量为707 mA h g^(-1))和长效的循环稳定性.更重要的是,基于Co/CNTBs催化剂的高硫载量电池(6.72 mg cm^(-2))在0.1 C下循环100圈后仍具有4.81 mA h cm^(-2)的高面积容量.本工作为高性能超结构杂化碳材料的原位接枝合成策略带来了新的思路,有望用于众多具有挑战性的应用.
文摘基于固态电解质的高安全性和高能量密度锂金属电池有望成为下一代储能器件.然而,固态电解质在高离子电导率与优良机械性能之间难以兼得,严重阻碍了其实际应用.本文利用多孔高分子刷(刚性多孔超交联聚氯甲基苯乙烯纳米球(xPCMS)表面接枝聚甲基丙烯酸缩水甘油酯(PGMA),xPCMS-g-PGMA)作为纳米填料,将其与聚乙二醇二胺(DPEG)、聚乙二醇二缩水甘油醚(PEGDE)进行交联,并引入电解液塑化剂后成功获得了一类坚韧的全有机复合电解质(xPCMS-g-PGMA-AOCE).刚性多孔xPCMS骨架可以增强复合膜的机械强度并为锂离子传输提供充足通道;毛发状反应性PGMA侧链有利于xPCMS-g-PGMA与DPEG、PEGDE等锂离子传输连续相之间形成均匀的三维交联网络结构,可以进一步提高膜力学性能以及促进锂离子均匀、快速传输.因此,基于xPCMS-g-PGMA-AOCE组装的锂金属电池在1 C电流密度下首圈放电比容量高达155 mAh g^(-1),循环360圈后容量保持率为88%.
基金National Natural Science Foundation of China,Grant/Award Numbers:51872336,51925308,52172061National Key Research and Development Program of China,Grant/Award Number:2021YFF0500600+2 种基金Pearl River Talent Plan of Guangdong,Grant/Award Number:2017GC010612Natural Science Foundation of Guangdong,Grant/Award Number:2021A1515011617Science and Technology Program of Guangzhou,Grant/Award Numbers:202102021111,202002020041。
文摘Lithium-sulfur(Li-S)batteries have been regarded as promising next-generation energy-storage devices owing to their inherently high theoretical energy density.Unfortunately,the poor capacity and cycling life caused by severe polysulfide shuttle effect and sluggish redox kinetics in sulfur cathodes greatly impede the practical application of Li-S batteries.Herein,a new class of nanonetworkstructured carbon decorated with oxygen-vacancy-containing cerium oxide nanoparticles(NSC-CeO_(2−x)),in which carbon skeleton is composed of highly conductive carbon nanotube core welded by hybrid carbon shell,has been developed via one-step heating treatment of hybrid molecular brush and further employed as functional interlayer to modify separator of Li-S battery.Owing to the synergistic effect of the highly active CeO_(2−x)nanoparticles and the threedimensional carbon nanonetwork in enhancing the preservation of the soluble polysulfides and boosting the redox kinetics of sulfur species,the NSC-CeO_(2−x)significantly promotes the electrochemical performance of sulfur cathode.As a result,the as-constructed Li-S batteries exhibit an ultrahigh initial sulfur utilization of 92.9%and an extremely large capacity of 751mA h g^(−1) at a high rate of 5 C.Remarkably,a stable capacity of 728 mA h g^(−1)over 300 cycles at 1 C is also achieved.
