The careful design of nano-architectures and smart hybridization of expected active materials can lead to more advanced properties. Here we have engineered a novel hierarchical branching Cu/Cu2O/CuO heteronanostructur...The careful design of nano-architectures and smart hybridization of expected active materials can lead to more advanced properties. Here we have engineered a novel hierarchical branching Cu/Cu2O/CuO heteronanostructure by combining a facile hydrothermal method and subsequent controlled oxidation process. The fine structure and epitaxial relationship between the branches and backbone are investigated by high-resolution transmission electron microscopy. Moreover, the evolution of the branch growth has also been observed during the gradual oxidation of the Cu nanowire surface. The experimental results suggest that the surface oxidation needs to be performed via a two-step exposure process to varying humidity in order to achieve optimized formation of a core-shell structured branching architecture. Finally, a proof-of-concept of the function of such a hierarchical framework as the anode material in lithium-ion batteries is demonstrated. The branching core-shell heterostructure improves battery performance by several means： （i） The epitaxially grown branches provide a high surface area for enhanced electrolyte accessibility and high resistance to volume change induced by Li^＋ intercalation/extraction; （ii） the core-shell structure with its well-defined heterojunction increases the contact area which facilitates effective charge transport during lithiation; （iii） the copper core acts as a current collector as well as providing structural reinforcement.展开更多
文摘本文以聚苯乙烯球为模板,杨梅单宁/Cu2+混合物为前驱体,制备了三维有序多孔碳内嵌纳米Cu_2O-CuO(3D Cu_2O-CuO@C)锂离子电池负极材料。采用多种技术手段研究了3D Cu_2O-CuO@C结构形貌及其电化学性能。3D Cu_2O-CuO@C在电流密度为1.0 A·g-1的循环性能测试中,500次循环后其放电比容量为635.8 m A·h·g^(-1),表现出了高循环稳定性。在电流密度为8.0 A·g-1的大电流条件下,其放电比容量仍维持在173.4 m A·h·g^(-1),表现出了优异的高倍率性能。
基金Supported by National Natural Science Foundation of China(2067100220490217)+3 种基金the State Education Ministry(EYTPSRFfor ROCSSRFDP 20070370001)Science and Technological Fund of Anhui Province for Outstanding Youth(08040106906).
基金We thank Prof. Mingbo Wu （State Key Laboratory of Heavy Oil Processing, China University of Petroleum） for his help in experiments. This work was finandally supported by the Key Joint Foundation of PetroChina, the National Natural Science Foundation of China （Nos. 51271215, U1362202, and 21106185） and the PetroChina Key Programs on Oil Refinery Catalysts （No. 2010E-1908 and 2010E-1903）.
文摘The careful design of nano-architectures and smart hybridization of expected active materials can lead to more advanced properties. Here we have engineered a novel hierarchical branching Cu/Cu2O/CuO heteronanostructure by combining a facile hydrothermal method and subsequent controlled oxidation process. The fine structure and epitaxial relationship between the branches and backbone are investigated by high-resolution transmission electron microscopy. Moreover, the evolution of the branch growth has also been observed during the gradual oxidation of the Cu nanowire surface. The experimental results suggest that the surface oxidation needs to be performed via a two-step exposure process to varying humidity in order to achieve optimized formation of a core-shell structured branching architecture. Finally, a proof-of-concept of the function of such a hierarchical framework as the anode material in lithium-ion batteries is demonstrated. The branching core-shell heterostructure improves battery performance by several means： （i） The epitaxially grown branches provide a high surface area for enhanced electrolyte accessibility and high resistance to volume change induced by Li^＋ intercalation/extraction; （ii） the core-shell structure with its well-defined heterojunction increases the contact area which facilitates effective charge transport during lithiation; （iii） the copper core acts as a current collector as well as providing structural reinforcement.
