对锂离子电池日益增长的市场需求已经引起巨大的研究热情来开发具有更高容量和超长循环性的新型电极材料.由于具有独特的平面结构限域性能,二维材料及其异质结构目前成为材料研究领域的热点,并有望在电化学能量储存方面发挥巨大的潜力....对锂离子电池日益增长的市场需求已经引起巨大的研究热情来开发具有更高容量和超长循环性的新型电极材料.由于具有独特的平面结构限域性能,二维材料及其异质结构目前成为材料研究领域的热点,并有望在电化学能量储存方面发挥巨大的潜力.因此,本文借助于微波化学策略把超薄SnO_2纳米片与石墨烯薄层耦合在一起构筑一种面对面型二维异质结构,利用其独特的平面结构限域性能来获得高可逆性的电化学储锂性能.实验结果表明,所制备的二维SnO_2/石墨烯异质结构表现出良好的电化学性能,连续500次循环之后其可逆容量仍能保持在688.5 mA h g-1,同时也具有很好的倍率性能.本工作揭示了具有面对面型二维异质结构在能量储存与转化设备应用方面的明显优势,为新型电极材料的制备提供了更多选择.展开更多
应.这种独特的结构不仅可以暴露更多的活性位点、缩短离子/电子扩散路径,还可以确保良好的结构稳定性,抑制重复循环过程中的结构应变.本文通过模板导向策略合成多级花状纯相尖晶石锰基氧化物纳米片.通过醇辅助水热法,利用"气泡反应...应.这种独特的结构不仅可以暴露更多的活性位点、缩短离子/电子扩散路径,还可以确保良好的结构稳定性,抑制重复循环过程中的结构应变.本文通过模板导向策略合成多级花状纯相尖晶石锰基氧化物纳米片.通过醇辅助水热法,利用"气泡反应"原理获得的碳酸盐分解来制备取向模板.最终产物尖晶石锰基氧化物纳米片同时满足优异的倍率性能和循环稳定性要求.合成的分层花状高压LiNi(0.5)Mn(1.5)O4(LNMO-HF)元素分布均匀,且无杂相. LNMOHF可以提供142.6 mA h g^-1的高放电容量,在55℃、1C下,其比能量密度为660.7 W h kg^-1.此外,利用这种模板导向策略合成的LiMn2O4(LMO),在1000次循环后,其容量保持率可达88.12%.展开更多
Tin dioxide(SnO2) and La-doped(1%,5%,10% in mass ratio) SnO2 samples were prepared via a hydrothermal method. The as-prepared powders were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM) ...Tin dioxide(SnO2) and La-doped(1%,5%,10% in mass ratio) SnO2 samples were prepared via a hydrothermal method. The as-prepared powders were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM) . Results showed that the particle size of SnO2 decreased gradually with the increase of the doped La element. When used as anode materials of Li ion battery,the La-doped samples exhibited better cycling performance than the pure SnO2,and the cycling performance of the La-doped samples got better and better with the increase of the doped La. The better electrochemical performance of the doped material could be attributed to the doping of La element,which not only enabled SnO2 powders to have a good dispersivity but also reduced their particle size.展开更多
Nd-doped(2%,5%,10% in mass ratio) SnO2 powders were prepared via a facile hydrothermal procedure.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emme...Nd-doped(2%,5%,10% in mass ratio) SnO2 powders were prepared via a facile hydrothermal procedure.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Teller(BET) specific surface area analyzers.Results showed that the Nd-doped SnO2 samples had more uniform and smaller primary particles compared with the pure sample,the particle size of the doped SnO2 decreased gradually with the increase of Nd,and the specific surface area also increased with the increase of the doped Nd.When used as gas sensing materials,the 5% and 10% Nd-doped sample showed high sensitivity and selectivity to ethanol.Furthermore,the Nd-doped sample showed fast response and recovery time to ethanol gas.This could be attributed to their small diameter,large surface area and Nd element doping.展开更多
Pure SnO2 and Ce-doped(1%,4%,7%,10% in mass ratio) SnO2 powders were prepared by a simple sol-gel method.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Bruna...Pure SnO2 and Ce-doped(1%,4%,7%,10% in mass ratio) SnO2 powders were prepared by a simple sol-gel method.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Teller(BET) specific surface area analyzers.Results showed that the 7% Ce-doped sample has a particle size of 0.1-0.3 μm with a narrow particle size distribution while the pure SnO2 was consisted of large agglomerated particles with a diameter up to several micrometers.When used as the catalyst to degrade methyl orange(MO),the 7% Ce-doped sample showed best photocatalytic property.These properties can be attributed to the large surface area and small particle size of the 7% Ce-doped sample.展开更多
基金supported by China Ministry of Science and Technology under Contract of 2016YFA(0202801)the National Natural Science Foundation of China(21521091,21390393,U1463202,21471089,21671117,21703219 and 21371023)China Postdoctoral Science Foundation(2017M620738)
文摘对锂离子电池日益增长的市场需求已经引起巨大的研究热情来开发具有更高容量和超长循环性的新型电极材料.由于具有独特的平面结构限域性能,二维材料及其异质结构目前成为材料研究领域的热点,并有望在电化学能量储存方面发挥巨大的潜力.因此,本文借助于微波化学策略把超薄SnO_2纳米片与石墨烯薄层耦合在一起构筑一种面对面型二维异质结构,利用其独特的平面结构限域性能来获得高可逆性的电化学储锂性能.实验结果表明,所制备的二维SnO_2/石墨烯异质结构表现出良好的电化学性能,连续500次循环之后其可逆容量仍能保持在688.5 mA h g-1,同时也具有很好的倍率性能.本工作揭示了具有面对面型二维异质结构在能量储存与转化设备应用方面的明显优势,为新型电极材料的制备提供了更多选择.
基金financially supported by the National Natural Science Foundation of China(21371023)
文摘应.这种独特的结构不仅可以暴露更多的活性位点、缩短离子/电子扩散路径,还可以确保良好的结构稳定性,抑制重复循环过程中的结构应变.本文通过模板导向策略合成多级花状纯相尖晶石锰基氧化物纳米片.通过醇辅助水热法,利用"气泡反应"原理获得的碳酸盐分解来制备取向模板.最终产物尖晶石锰基氧化物纳米片同时满足优异的倍率性能和循环稳定性要求.合成的分层花状高压LiNi(0.5)Mn(1.5)O4(LNMO-HF)元素分布均匀,且无杂相. LNMOHF可以提供142.6 mA h g^-1的高放电容量,在55℃、1C下,其比能量密度为660.7 W h kg^-1.此外,利用这种模板导向策略合成的LiMn2O4(LMO),在1000次循环后,其容量保持率可达88.12%.
基金Project supported by the National Natural Science Foundation of China (20871107)Henan Outstanding Youth Science Fund (0612002700)the Natural Science Foundation of the Education Department of Henan Province (2009A150031)
文摘Tin dioxide(SnO2) and La-doped(1%,5%,10% in mass ratio) SnO2 samples were prepared via a hydrothermal method. The as-prepared powders were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM) . Results showed that the particle size of SnO2 decreased gradually with the increase of the doped La element. When used as anode materials of Li ion battery,the La-doped samples exhibited better cycling performance than the pure SnO2,and the cycling performance of the La-doped samples got better and better with the increase of the doped La. The better electrochemical performance of the doped material could be attributed to the doping of La element,which not only enabled SnO2 powders to have a good dispersivity but also reduced their particle size.
基金Project supported by the National Natural Science Foundation of China (20871107)He'nan Outstanding Youth Science Fund (0612002700)the Natural Science Foundation of the Education Department of Henan Province (2009A150031)
文摘Nd-doped(2%,5%,10% in mass ratio) SnO2 powders were prepared via a facile hydrothermal procedure.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Teller(BET) specific surface area analyzers.Results showed that the Nd-doped SnO2 samples had more uniform and smaller primary particles compared with the pure sample,the particle size of the doped SnO2 decreased gradually with the increase of Nd,and the specific surface area also increased with the increase of the doped Nd.When used as gas sensing materials,the 5% and 10% Nd-doped sample showed high sensitivity and selectivity to ethanol.Furthermore,the Nd-doped sample showed fast response and recovery time to ethanol gas.This could be attributed to their small diameter,large surface area and Nd element doping.
基金Project supported by the National Natural Science Foundation of China (20871107)He'nan Outstanding Youth Science Fund (0612002700)the Natural Science Foundation of the Education Department of Henan Province (2009A150031)
文摘Pure SnO2 and Ce-doped(1%,4%,7%,10% in mass ratio) SnO2 powders were prepared by a simple sol-gel method.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Teller(BET) specific surface area analyzers.Results showed that the 7% Ce-doped sample has a particle size of 0.1-0.3 μm with a narrow particle size distribution while the pure SnO2 was consisted of large agglomerated particles with a diameter up to several micrometers.When used as the catalyst to degrade methyl orange(MO),the 7% Ce-doped sample showed best photocatalytic property.These properties can be attributed to the large surface area and small particle size of the 7% Ce-doped sample.
