A Ni Fe_2O_4/expanded graphite(Ni Fe_2O_4/EG)nanocomposite was prepared via a simple and inexpensive synthesis method. Its lithium storage properties were studied with the goal of applying it as an anode in a lithium-...A Ni Fe_2O_4/expanded graphite(Ni Fe_2O_4/EG)nanocomposite was prepared via a simple and inexpensive synthesis method. Its lithium storage properties were studied with the goal of applying it as an anode in a lithium-ion battery. The obtained nanocomposite exhibited a good cycle performance, with a capacity of 601 m Ah g^(-1)at a current of 1 A g^(-1)after 800 cycles. This good performance may beattributed to the enhanced electrical conductivity and layered structure of the EG. Its high mechanical strength could postpone the disintegration of the nanocomposite structure,efficiently accommodate volume changes in the Ni Fe_2O_4-based anodes, and alleviate aggregation of Ni Fe_2O_4 nanoparticles.展开更多
以天然鳞片石墨为原料,利用电泳插层法制备出具有适当膨胀体积的微膨石墨,石墨的结构缺陷增多,具有较大的比表面积和增大的石墨层间距。微膨石墨的可逆容量可以达到521 m Ah/g;在0.2 C倍率循环充放电30次容量最佳可保持在99%以上,在1.0 ...以天然鳞片石墨为原料,利用电泳插层法制备出具有适当膨胀体积的微膨石墨,石墨的结构缺陷增多,具有较大的比表面积和增大的石墨层间距。微膨石墨的可逆容量可以达到521 m Ah/g;在0.2 C倍率循环充放电30次容量最佳可保持在99%以上,在1.0 C循环50次其容量可稳定在188 m Ah/g,且表现出良好的倍率性能。微膨石墨电化学性能的改善得益于其具有适当的比表面积及内部结构的改变。交流阻抗测试显示微膨石墨的SEI膜阻抗和电荷传递阻抗小于鳞片石墨,具有良好的电化学活性。展开更多
MoS2 is a promising anode material for sodium ion batteries owing to its two-dimensional layered structure and high specific capacity. But it still exhibits a poor cycle stability and limited rate capability for Na＋ ...MoS2 is a promising anode material for sodium ion batteries owing to its two-dimensional layered structure and high specific capacity. But it still exhibits a poor cycle stability and limited rate capability for Na＋ storage because of its poor electrical conductivity and structural instability. In this work, MoS2/graphite composite is fabricated by mechanically delaminated and restacked MoS2 and graphite to form two-dimensional composite layers. The graphite sheets will improve electrical conductivity and prevent the aggregation as well as structure collapse of the MoS2 layers during charge-discharge process. The MoS2/graphite composite exhibits excellent Na＋ storage properties. It delivers a high discharge specific capacity of 358.2 mAh/g at a current density of 100 mA]g in the first discharge process and with capacity retention of 68.1% after 800 cycles （retains 244 mAh/g）. The average discharge specific capacities retain 250.9 and 225.4 mAh/g corresponding to the current densities of 100 and 1000 mA]g, showing excellent rate capability. The improved electrochemical performance is attributed to the improved electrical conductivity and structural stability after composition of graphite sheets. The study demonstrates a new research strategy for improving sodium ion storage properties of Mo52.展开更多
通过对多晶硅生产副产物SiCl_4水解工艺的设计和优化制备出了SiO_2溶胶,并与原料微米Si粉、球形天然石墨、葡萄糖等通过液相复合、机械球磨、二次包覆、高温热解等制备出了NG&Si&SiO_x锂离子电池负极材料。采用X射线衍射仪、扫...通过对多晶硅生产副产物SiCl_4水解工艺的设计和优化制备出了SiO_2溶胶,并与原料微米Si粉、球形天然石墨、葡萄糖等通过液相复合、机械球磨、二次包覆、高温热解等制备出了NG&Si&SiO_x锂离子电池负极材料。采用X射线衍射仪、扫描电镜对所制备的材料进行了结构和形貌表征;采用恒流充放电测试仪对样品的电化学性能进行了测试;采用电化学工作站对材料的交流阻抗性能进行了测试。所制备样品与球形天然石墨(NG)比较,从第6周循环后比容量稳定在484 m A·h·g^(-1),具有较高的可逆比容量和良好的循环性能。展开更多
基金support from the National Basic Research Program of China (2014CB239702)National Natural Science Foundation of China (Grant Nos. 21371121, 21506126 and 51502174)+1 种基金Shenzhen Science and Technology Research Foundation (Grant Nos. JCYJ20150324141711645,JCYJ20150324141711616 and JCYJ20150626090504916)China Postdoctoral Science Foundation (2015 M582401 and 2015 M572349)
文摘A Ni Fe_2O_4/expanded graphite(Ni Fe_2O_4/EG)nanocomposite was prepared via a simple and inexpensive synthesis method. Its lithium storage properties were studied with the goal of applying it as an anode in a lithium-ion battery. The obtained nanocomposite exhibited a good cycle performance, with a capacity of 601 m Ah g^(-1)at a current of 1 A g^(-1)after 800 cycles. This good performance may beattributed to the enhanced electrical conductivity and layered structure of the EG. Its high mechanical strength could postpone the disintegration of the nanocomposite structure,efficiently accommodate volume changes in the Ni Fe_2O_4-based anodes, and alleviate aggregation of Ni Fe_2O_4 nanoparticles.
文摘以天然鳞片石墨为原料,利用电泳插层法制备出具有适当膨胀体积的微膨石墨,石墨的结构缺陷增多,具有较大的比表面积和增大的石墨层间距。微膨石墨的可逆容量可以达到521 m Ah/g;在0.2 C倍率循环充放电30次容量最佳可保持在99%以上,在1.0 C循环50次其容量可稳定在188 m Ah/g,且表现出良好的倍率性能。微膨石墨电化学性能的改善得益于其具有适当的比表面积及内部结构的改变。交流阻抗测试显示微膨石墨的SEI膜阻抗和电荷传递阻抗小于鳞片石墨,具有良好的电化学活性。
基金supported by the National Natural Science Foundation of China(no.21403099)the Natural Science Funds for Distinguished Young Scholars of Gansu Province(no.1606RJDA320)
文摘MoS2 is a promising anode material for sodium ion batteries owing to its two-dimensional layered structure and high specific capacity. But it still exhibits a poor cycle stability and limited rate capability for Na＋ storage because of its poor electrical conductivity and structural instability. In this work, MoS2/graphite composite is fabricated by mechanically delaminated and restacked MoS2 and graphite to form two-dimensional composite layers. The graphite sheets will improve electrical conductivity and prevent the aggregation as well as structure collapse of the MoS2 layers during charge-discharge process. The MoS2/graphite composite exhibits excellent Na＋ storage properties. It delivers a high discharge specific capacity of 358.2 mAh/g at a current density of 100 mA]g in the first discharge process and with capacity retention of 68.1% after 800 cycles （retains 244 mAh/g）. The average discharge specific capacities retain 250.9 and 225.4 mAh/g corresponding to the current densities of 100 and 1000 mA]g, showing excellent rate capability. The improved electrochemical performance is attributed to the improved electrical conductivity and structural stability after composition of graphite sheets. The study demonstrates a new research strategy for improving sodium ion storage properties of Mo52.
文摘通过对多晶硅生产副产物SiCl_4水解工艺的设计和优化制备出了SiO_2溶胶,并与原料微米Si粉、球形天然石墨、葡萄糖等通过液相复合、机械球磨、二次包覆、高温热解等制备出了NG&Si&SiO_x锂离子电池负极材料。采用X射线衍射仪、扫描电镜对所制备的材料进行了结构和形貌表征;采用恒流充放电测试仪对样品的电化学性能进行了测试;采用电化学工作站对材料的交流阻抗性能进行了测试。所制备样品与球形天然石墨(NG)比较,从第6周循环后比容量稳定在484 m A·h·g^(-1),具有较高的可逆比容量和良好的循环性能。
