title: Lithium Storage in Microstructures of Amorphous Mixed-Valence Vanadium Oxide as Anode Materials.
abstract: Constructing three-dimensional (3 D) nanostructures with excellent structural stability is an important approach for realizing high-rate capability and a high capacity of the electrode materials in lithium-ion batteries (LIBs). Herein, we report the synthesis of hydrangea-like amorphous mixed-valence VOx microspheres (a-VOx MSs) through a facile solvothermal method followed by controlled calcination. The resultant hydrangea-like a-VOx MSs are composed of intercrossed nanosheets and, thus, construct a 3 D network structure. Upon evaluation as an anode material for LIBs, the a-VOx MSs show excellent lithium-storage performance in terms of high capacity, good rate capability, and long-term stability upon extended cycling. Specifically, they exhibit very stable cycling behavior with a highly reversible capacity of 1050 mA h g(-1) at a rate of 0.1 A g(-1) after 140 cycles. They also show excellent rate capability, with a capacity of 390 mA h g(-1) at a rate as high as 10 A g(-1) . Detailed investigations on the morphological and structural changes of the a-VOx MSs upon cycling demonstrated that the a-VOx MSs went through modification of the local VO coordinations accompanied with the formation of a higher oxidation state of V, but still with an amorphous state throughout the whole discharge/charge process. Moreover, the a-VOx MSs can buffer huge volumetric changes during the insertion/extraction process, and at the same time they remain intact even after 200 cycles of the charge/discharge process. Thus, these microspheres may be a promising anode material for LIBs.
authors.affiliation: Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic, Electrophotonic Conversion Materials, Department of Chemistry, Beijing Institute of Technology, Beijing 100081 (PR China).
authors.forename: Di
authors.initials: D
authors.lastname: Zhao
authors.affiliation: Institute of High Energy Physics, The Chinese Academy of Sciences, Beijing 100049 (PR China).
authors.forename: Lirong
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic, Electrophotonic Conversion Materials, Department of Chemistry, Beijing Institute of Technology, Beijing 100081 (PR China).
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic, Electrophotonic Conversion Materials, Department of Chemistry, Beijing Institute of Technology, Beijing 100081 (PR China).
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic, Electrophotonic Conversion Materials, Department of Chemistry, Beijing Institute of Technology, Beijing 100081 (PR China). caomh@bit.edu.cn.
authors.forename: Minhua
authors.initials: M
authors.lastname: Cao
mesh_terms: D011211:Electric Power Supplies; D004563:Electrochemistry; D004566:Electrodes; D008094:Lithium / Q000737:chemistry; D008863:Microspheres; D010087:Oxides / Q000737:chemistry*; D014639:Vanadium / Q000737:chemistry*
chemical_list: D010087:Oxides; D014639:Vanadium; D008094:Lithium
keywords: amorphous materials; lithium-ion batteries; microspheres; mixed-valent compounds; vanadium oxide