A simple strategy to prepare a hybrid of nanocomposites of anatase TiO2/graphene nanosheets （GNS） as anode materials for lithium-ion batteries was reported.The morphology and crystal structure were studied by X-ray ...A simple strategy to prepare a hybrid of nanocomposites of anatase TiO2/graphene nanosheets （GNS） as anode materials for lithium-ion batteries was reported.The morphology and crystal structure were studied by X-ray diffraction （XRD）,field emission scanning electron microscopy （FE-SEM） and transmission electron microscopy （TEM）.The electrochemical performance was evaluated by galvanostatic charge-lischarge tests and alternating current （AC） impedance spectroscopy.The results show that the TiO2/GNS electrode exhibit higher electrochemical performance than that of TiO2 electrode regardless of the rate.Even at 500 mA/g,the capacity of TiO2/GNS is 120.3 mAh/g,which is higher than that of TiO2 61.6 mAh/g.The high performance is attributed to the addition of graphene to improve electrical conductivity and reduce polarization.展开更多
TiO2-B was synthesized by solid-state reaction. The structures, surface morphologies and electrochemical performances of TiO2-B were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） ...TiO2-B was synthesized by solid-state reaction. The structures, surface morphologies and electrochemical performances of TiO2-B were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurement, respectively. The effects of calcining temperature, molar ratio of K2O to TiO2 and calcining time on the characteristics of TiO2-B were investigated. The results show that the calcining time exerts a significant influence on the electrochemical performances of TiO2-B. The TiO2-B is obtained with good crystal structure and suitable size by using K2Ti4O9, which is prepared at 950 ℃for 24 h under the condition of x（K2O）/x（TiO2）=1：3.5. The TiO2-B delivers all initial discharge capacity of 231.6 mA.h/g. And the rate caoacitv is 73.2 mA-h/g at 1 675 mA/g, which suggests that TiO2-B is a promising anode material for the lithium ion batteries.展开更多
以石墨烯、Ni SO4、K2S2O8(饱和)、氨水、蒸馏水为反应物,经过常温回流制备得到Ni OOH/Ni(OH)2含量不同的石墨烯/Ni OOH/Ni(OH)2复合材料。扫描电子显微镜法(SEM)表征显示,Ni(OH)2/Ni OOH在石墨烯表面上形成多孔结构,负载了多孔Ni OOH/N...以石墨烯、Ni SO4、K2S2O8(饱和)、氨水、蒸馏水为反应物,经过常温回流制备得到Ni OOH/Ni(OH)2含量不同的石墨烯/Ni OOH/Ni(OH)2复合材料。扫描电子显微镜法(SEM)表征显示,Ni(OH)2/Ni OOH在石墨烯表面上形成多孔结构,负载了多孔Ni OOH/Ni(OH)2的石墨烯又进行了层层堆积。电化学性能测试显示,电极材料GP/Ni-5性能最佳,其在电流密度为100 m A/g时,首次可逆比容量为1 287.4 m Ah/g,80次循环后比容量保持在830 m Ah/g,而纯Ni OOH/Ni(OH)2首次可逆比容量为2 400.6 m Ah/g,80次循环后比容量已降至405.9 m Ah/g,表明石墨烯的加入大大提高了材料的稳定性。展开更多
It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomate rials can be significantly improved by an incorporation of carbon additives.In the study,we develop a novel Ndoped TiO2 me...It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomate rials can be significantly improved by an incorporation of carbon additives.In the study,we develop a novel Ndoped TiO2 mesoporous nanostructure via the addition of carbon quantum dots(CQDs)solution following a scalable hydrothermal process.The as-made TiO2 product shows well-defined morphology,high conductivity,large surface area,and abundant mesopores.When evaluated as anodes for sodiumion batteries,the CQDs@TiO2 product annealed at 500℃exhibits a superior sodium storage capability.It delivers a high reversible capacity of 168.8 mAh/g at 100 mA/g over 500 cycles and long cycling stability.The remarkable performance of CQDs@TiO2 mainly arises from the large surface area and mesoporous architecture constructed by ultrathin TiO2 nanosheets,as well as the full coope ration between CQDs and TiO2.展开更多
基金Project(Y4110230)supported by Natural Science Foundation of Zhejiang Province,ChinaProject(51204146,51101140)supported by the National Natural Science Foundation of ChinaProject(2012M521197)supported by Postdoctoral Science Foundation of China
文摘A simple strategy to prepare a hybrid of nanocomposites of anatase TiO2/graphene nanosheets （GNS） as anode materials for lithium-ion batteries was reported.The morphology and crystal structure were studied by X-ray diffraction （XRD）,field emission scanning electron microscopy （FE-SEM） and transmission electron microscopy （TEM）.The electrochemical performance was evaluated by galvanostatic charge-lischarge tests and alternating current （AC） impedance spectroscopy.The results show that the TiO2/GNS electrode exhibit higher electrochemical performance than that of TiO2 electrode regardless of the rate.Even at 500 mA/g,the capacity of TiO2/GNS is 120.3 mAh/g,which is higher than that of TiO2 61.6 mAh/g.The high performance is attributed to the addition of graphene to improve electrical conductivity and reduce polarization.
基金Project(2007BAE12B01) supported by the National Key Technology R&D Program of China
文摘TiO2-B was synthesized by solid-state reaction. The structures, surface morphologies and electrochemical performances of TiO2-B were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurement, respectively. The effects of calcining temperature, molar ratio of K2O to TiO2 and calcining time on the characteristics of TiO2-B were investigated. The results show that the calcining time exerts a significant influence on the electrochemical performances of TiO2-B. The TiO2-B is obtained with good crystal structure and suitable size by using K2Ti4O9, which is prepared at 950 ℃for 24 h under the condition of x（K2O）/x（TiO2）=1：3.5. The TiO2-B delivers all initial discharge capacity of 231.6 mA.h/g. And the rate caoacitv is 73.2 mA-h/g at 1 675 mA/g, which suggests that TiO2-B is a promising anode material for the lithium ion batteries.
文摘以石墨烯、Ni SO4、K2S2O8(饱和)、氨水、蒸馏水为反应物,经过常温回流制备得到Ni OOH/Ni(OH)2含量不同的石墨烯/Ni OOH/Ni(OH)2复合材料。扫描电子显微镜法(SEM)表征显示,Ni(OH)2/Ni OOH在石墨烯表面上形成多孔结构,负载了多孔Ni OOH/Ni(OH)2的石墨烯又进行了层层堆积。电化学性能测试显示,电极材料GP/Ni-5性能最佳,其在电流密度为100 m A/g时,首次可逆比容量为1 287.4 m Ah/g,80次循环后比容量保持在830 m Ah/g,而纯Ni OOH/Ni(OH)2首次可逆比容量为2 400.6 m Ah/g,80次循环后比容量已降至405.9 m Ah/g,表明石墨烯的加入大大提高了材料的稳定性。
基金financial support from the Shuguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.18SG035)Shanghai Pujiang Program(No.17PJD015)。
文摘It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomate rials can be significantly improved by an incorporation of carbon additives.In the study,we develop a novel Ndoped TiO2 mesoporous nanostructure via the addition of carbon quantum dots(CQDs)solution following a scalable hydrothermal process.The as-made TiO2 product shows well-defined morphology,high conductivity,large surface area,and abundant mesopores.When evaluated as anodes for sodiumion batteries,the CQDs@TiO2 product annealed at 500℃exhibits a superior sodium storage capability.It delivers a high reversible capacity of 168.8 mAh/g at 100 mA/g over 500 cycles and long cycling stability.The remarkable performance of CQDs@TiO2 mainly arises from the large surface area and mesoporous architecture constructed by ultrathin TiO2 nanosheets,as well as the full coope ration between CQDs and TiO2.
