title: ZnO/CoO and ZnCo2O4 Hierarchical Bipyramid Nanoframes: Morphology Control, Formation Mechanism, and Their Lithium Storage Properties.
abstract: Mastery over the structure of nanoscale materials can effectively tailor and regulate their electrochemical properties, enabling improvement in both rate capability and cycling stability. We report the shape-controlled synthesis of novel mesoporous bicomponent-active ZnO/CoO hierarchical multilayered bipyramid nanoframes (HMBNFs). The as-synthesized micro/nanocrystals look like multilayered bipyramids and consist of a series of structural units with similar frames and uniform sheet branches. The use of an appropriate straight-chain monoalcohol was observed to be critical for the formation of HMBNFs. In addition, the structure of HMBNFs could be preserved only in a limited range of the precursor ratio. An extremely fast crystal growth process and an unusual transverse crystallization of the ZnCo-carbonate HMBNFs were newly discovered and proposed. By calcination of ZnCo-carbonate HMBNFs at the atmosphere of nitrogen and air, ZnO/CoO and ZnCo2O4 HMBNFs were obtained, respectively. Compared to the ZnCo2O4 HMBNFs, the ZnO/CoO HMBNFs with a uniform distribution of nanocrystal ZnO and CoO subunits exhibited enhanced electrochemical activity, including greater rate capability and longer cycling performance, when evaluated as an anode material for Li-ion batteries. The superior electrochemical performance of the ZnO/CoO HMBNFs is attributed to the unique nanostructure, bicomponent active synergy, and uniform distribution of ZnO and CoO phases at the nanoscale.
authors.affiliation: Key Laboratory for Colloid and Interface Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, P. R. China.
authors.forename: Jing
authors.initials: J
authors.lastname: Bai
authors.affiliation: Key Laboratory for Colloid and Interface Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, P. R. China.
authors.forename: Kaiqi
authors.initials: K
authors.lastname: Wang
authors.affiliation: Key Laboratory for Colloid and Interface Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, P. R. China.
authors.forename: Jinkui
authors.initials: J
authors.lastname: Feng
authors.affiliation: Key Laboratory for Colloid and Interface Chemistry, Ministry of Education, and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, P. R. China.|Institute of Physical Chemistry, Zhejiang Normal University , Jinhua 321004, China.
authors.forename: Shenglin
authors.initials: S
authors.lastname: Xiong
keywords: anodes; bipyramid; lithium-ion batteries; nanoframes; synergistic effect