Recent experimental breakthroughs open up new opportunities for magnetism in few-atomic-layer twodimensional(2 D) materials, which makes fabrication of new magnetic 2 D materials a fascinating issue.Here, we report th...Recent experimental breakthroughs open up new opportunities for magnetism in few-atomic-layer twodimensional(2 D) materials, which makes fabrication of new magnetic 2 D materials a fascinating issue.Here, we report the growth of monolayer VSe_2 by molecular beam epitaxy(MBE) method. Electronic properties measurements by scanning tunneling spectroscopy(STS) method revealed that the asgrown monolayer VSe_2 has magnetic characteristic peaks in its electronic density of states and a lower work-function at its edges. Moreover, air exposure experiments show air-stability of the monolayer VSe_2. This high-quality monolayer VSe_2, a very air-inert 2 D material with magnetism and low edge work function, is promising for applications in developing next-generation low power-consumption, high efficiency spintronic devices and new electrocatalysts.展开更多
多层黑磷的带隙(~0.33 eV)覆盖~3.7微米光谱范围,在红外应用方面有巨大潜力.然而进一步降低带隙使其可用于远红外器件仍面临挑战.此外,黑磷材料及器件饱受空气稳定性差的困扰.因此,我们提出了同系物砷取代的策略,实现了对黑磷带隙的调...多层黑磷的带隙(~0.33 eV)覆盖~3.7微米光谱范围,在红外应用方面有巨大潜力.然而进一步降低带隙使其可用于远红外器件仍面临挑战.此外,黑磷材料及器件饱受空气稳定性差的困扰.因此,我们提出了同系物砷取代的策略,实现了对黑磷带隙的调控和稳定性的增强.通过优化化学气相传输的生长参数,我们制备出砷含量可控的毫米级黑磷母体.经扫描隧道显微镜和能谱分析,砷原子随机嵌入黑磷的主晶格中并保留了原有几近完美的晶格排列.对于60%砷含量的多层黑磷,其电学带隙降低至~0.16±0.02 eV并伴随强的p型掺杂.受益于较小的晶格畸变和强掺杂效应,基于砷取代黑磷的光电器件表现出高达约882 mA W^(-1)的光响应率,远超未取代的黑磷基光电器件(约314 mA W^(-1)).更为重要的是,砷取代的黑磷器件在暴露大气环境(温度~20℃;湿度~33%)48小时后未表现出明显的氧化迹象.本文为开发黑磷基、可长时间运行的光电探测器和光调制器件提供了新途径.展开更多
硫化物固体电解质是发展高容量锂硫电池的理想候选者.然而,同时提高硫化物固体电解质的离子导电性、空气稳定性和电解质/电极界面的相容性仍然是一个巨大的挑战.因此,我们提出了一种双掺杂(Sb_(2)O_(3)和LiI)策略来制备多功能硫化物固...硫化物固体电解质是发展高容量锂硫电池的理想候选者.然而,同时提高硫化物固体电解质的离子导电性、空气稳定性和电解质/电极界面的相容性仍然是一个巨大的挑战.因此,我们提出了一种双掺杂(Sb_(2)O_(3)和LiI)策略来制备多功能硫化物固体电解质.Sb_(2)O_(3)可以拓宽锂离子的传输路径和提高空气稳定性,而LiI可以抑制锂枝晶的生成和降低电解质/电极之间的电阻.因此,硫化物固体电解质在空气中和界面上的性能得到了增强,在30℃下的离子电导率为1.69×10^(-3)S cm^(-1),且具有很好的空气稳定性,对金属锂也很稳定.在此基础上,组装的全固态锂硫电池以0.05 C循环100圈后,表现出较高的放电比容量(室温,833 mA h g^(-1);60℃:949 mA h g^(-1)).本文为制备实用的硫化物固体电解质和高性能全固态锂硫电池提供了合理的方案.展开更多
钠离子电池中,正极材料至关重要,在很大程度上决定了整个电池的能量密度等性能.层状氧化物是钠离子电池中最有潜力的正极材料之一.然而,层状氧化物仍面临着不可逆相变、容量低、空气稳定性差和循环寿命短等缺点,限制了其实际应用.为了...钠离子电池中,正极材料至关重要,在很大程度上决定了整个电池的能量密度等性能.层状氧化物是钠离子电池中最有潜力的正极材料之一.然而,层状氧化物仍面临着不可逆相变、容量低、空气稳定性差和循环寿命短等缺点,限制了其实际应用.为了解决相关问题,本研究成功制备了中空结构的Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)多面体正极材料.其中,少量的大尺寸钾离子实现了对材料中相应钠离子的取代;镍离子的较高氧化还原电位使得氧化物正极材料能够在空气中稳定保存.在100 mA g^(-1)电流密度下放电100次后,仍可保持115.0 mA h g^(-1)的放电比容量.在500 mA g^(-1)的较大电流密度下,材料仍然可实现104.1 mA h g^(-1)的较高放电比容量.研究结果表明,充放电过程中,氧化物正极材料的P2到O2的相变得到了有效地抑制.同时钾离子在层间的嵌入掺杂,使得氧化物正极的钠离子层间距增大,提升了钠离子的迁移速率.因此,Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)应用于钠离子电池正极时展现出较大的吸引力和应用前景.展开更多
The P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method.The structures,morphologies and electrochemical performances of Na_(2/3)Fe_...The P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method.The structures,morphologies and electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were characterized thoroughly by means of X-ray diffractometer,scanning electron microscope and electrochemical charge/discharge instruments.Moreover,a thin layer of Al_(2)O_(3),which was formed on the surface of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2),can enhance the storage performance by preventing the formation of Na_(2)CO_(3)·H_(2)O,which is believed to enhance the electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials.This facile surface modification method may pave a way to synthesize advanced cathode materials for sodium-ion batteries.展开更多
基金supported by the National Natural Science Foundation of China(61725107,51572290 and 11334006)National Key Research&Development Projects of China(2016YFA0202301)+1 种基金National Basic Research Program of China(2013CBA01601)Strategic Priority Research Program(B)of Chinese Academy of Sciences(XDPB06)
文摘Recent experimental breakthroughs open up new opportunities for magnetism in few-atomic-layer twodimensional(2 D) materials, which makes fabrication of new magnetic 2 D materials a fascinating issue.Here, we report the growth of monolayer VSe_2 by molecular beam epitaxy(MBE) method. Electronic properties measurements by scanning tunneling spectroscopy(STS) method revealed that the asgrown monolayer VSe_2 has magnetic characteristic peaks in its electronic density of states and a lower work-function at its edges. Moreover, air exposure experiments show air-stability of the monolayer VSe_2. This high-quality monolayer VSe_2, a very air-inert 2 D material with magnetism and low edge work function, is promising for applications in developing next-generation low power-consumption, high efficiency spintronic devices and new electrocatalysts.
基金supported by the National Natural Science Foundation of China (52072138 and 51772115)the National Key Research and Development Program of China (2018YFE0206900)Australian Research Council (ARC) through the Discovery Project (DP180102297)。
基金supported by the Postgraduate Research and Practice Innovation Program of NUAA(xcxjh20210111)the National Natural Science Foundation of China(1210040808,61922082,and 12004180)+5 种基金the National Key Research and Development Program of China(2019YFA0705400)the Natural Science Foundation of Jiangsu Province(BK20210312 and BK20190018)the Fundamental Research Funds for the Central Universities(NS2020008 and NJ2019002)the Program for Innovative Talents and Entrepreneur in Jiangsuthe Research Fund for the State Key Laboratory of Mechanics and Control of Mechanical Structures(MCMS-I-0419G02)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘多层黑磷的带隙(~0.33 eV)覆盖~3.7微米光谱范围,在红外应用方面有巨大潜力.然而进一步降低带隙使其可用于远红外器件仍面临挑战.此外,黑磷材料及器件饱受空气稳定性差的困扰.因此,我们提出了同系物砷取代的策略,实现了对黑磷带隙的调控和稳定性的增强.通过优化化学气相传输的生长参数,我们制备出砷含量可控的毫米级黑磷母体.经扫描隧道显微镜和能谱分析,砷原子随机嵌入黑磷的主晶格中并保留了原有几近完美的晶格排列.对于60%砷含量的多层黑磷,其电学带隙降低至~0.16±0.02 eV并伴随强的p型掺杂.受益于较小的晶格畸变和强掺杂效应,基于砷取代黑磷的光电器件表现出高达约882 mA W^(-1)的光响应率,远超未取代的黑磷基光电器件(约314 mA W^(-1)).更为重要的是,砷取代的黑磷器件在暴露大气环境(温度~20℃;湿度~33%)48小时后未表现出明显的氧化迹象.本文为开发黑磷基、可长时间运行的光电探测器和光调制器件提供了新途径.
基金supported by the Science and Technology Support Plan of Tianjin(19YFZCGX00220)the National Natural Science Foundation of China(21935006)the Fundamental Research Funds for the Central Universities,Nankai University(63211043)。
文摘硫化物固体电解质是发展高容量锂硫电池的理想候选者.然而,同时提高硫化物固体电解质的离子导电性、空气稳定性和电解质/电极界面的相容性仍然是一个巨大的挑战.因此,我们提出了一种双掺杂(Sb_(2)O_(3)和LiI)策略来制备多功能硫化物固体电解质.Sb_(2)O_(3)可以拓宽锂离子的传输路径和提高空气稳定性,而LiI可以抑制锂枝晶的生成和降低电解质/电极之间的电阻.因此,硫化物固体电解质在空气中和界面上的性能得到了增强,在30℃下的离子电导率为1.69×10^(-3)S cm^(-1),且具有很好的空气稳定性,对金属锂也很稳定.在此基础上,组装的全固态锂硫电池以0.05 C循环100圈后,表现出较高的放电比容量(室温,833 mA h g^(-1);60℃:949 mA h g^(-1)).本文为制备实用的硫化物固体电解质和高性能全固态锂硫电池提供了合理的方案.
基金financially supported by the National Natural Science Foundation of China(91963118 and 52173246)the Science Technology Program of Jilin Province(20220508141RC)+1 种基金the Science and Technology Development Plan of Suzhou(ZXL2021176)the 111 Project(B13013)。
文摘钠离子电池中,正极材料至关重要,在很大程度上决定了整个电池的能量密度等性能.层状氧化物是钠离子电池中最有潜力的正极材料之一.然而,层状氧化物仍面临着不可逆相变、容量低、空气稳定性差和循环寿命短等缺点,限制了其实际应用.为了解决相关问题,本研究成功制备了中空结构的Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)多面体正极材料.其中,少量的大尺寸钾离子实现了对材料中相应钠离子的取代;镍离子的较高氧化还原电位使得氧化物正极材料能够在空气中稳定保存.在100 mA g^(-1)电流密度下放电100次后,仍可保持115.0 mA h g^(-1)的放电比容量.在500 mA g^(-1)的较大电流密度下,材料仍然可实现104.1 mA h g^(-1)的较高放电比容量.研究结果表明,充放电过程中,氧化物正极材料的P2到O2的相变得到了有效地抑制.同时钾离子在层间的嵌入掺杂,使得氧化物正极的钠离子层间距增大,提升了钠离子的迁移速率.因此,Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)应用于钠离子电池正极时展现出较大的吸引力和应用前景.
基金supported by the National Key Research and Development Program of China(2021YFE0111000)the National Natural Science Foundation of China(22109053,22179051,U1802257,and 61504118)+4 种基金Guangdong Basic and Applied Basic Research Foundation(2020A1515110548)the Natural Science Foundation of Guangdong Province(2019B151502061)Guangzhou Science and Technology Planning Project(202102020775 and 202102010091)the Scientific Research Fund of Yunnan Provincial Department of Education(2022Y188)the Key Applied Basic Research Program of Yunnan Province(202201AS070023)。
基金financially supported by the Natural Science Foundation of Hunan Province,China(No.2020JJ5755)the National Natural Science Foundation of China(Nos.51804344,51704332,51874360)the Innovation and Entrepreneurship Project of Hunan Province,China(No.2018GK5026)。
文摘The P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method.The structures,morphologies and electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were characterized thoroughly by means of X-ray diffractometer,scanning electron microscope and electrochemical charge/discharge instruments.Moreover,a thin layer of Al_(2)O_(3),which was formed on the surface of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2),can enhance the storage performance by preventing the formation of Na_(2)CO_(3)·H_(2)O,which is believed to enhance the electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials.This facile surface modification method may pave a way to synthesize advanced cathode materials for sodium-ion batteries.
