Chen Nan, Wang Chunzhong, Hu Fang, Bie Xiaofei, Wei Yingjin, Chen Gang, Du Fei
§School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, PR China.
∥Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Kyoto 615-8520, Japan.
ACS Appl Mater Interfaces. 2015 Jul 29;7(29):16117-23. doi: 10.1021/acsami.5b05030. Epub 2015 Jul 20.
Brannerite-type vanadium-molybdenum oxide LiVMoO6 is prepared by a facile liquid-phase method, and its electrochemical properties as anode of lithium-ion batteries are comprehensively studied by means of galvanostatic charge-discharge profiles, rate performance, and cyclic voltammetry. In the working voltage between 3.0 and 0.01 V, LiVMoO6 delivers a high reversible capacity of more than 900 mAh g(-1) at the current density of 100 mA g(-1) and a superior rate capability with discharge capacity of ca. 584 and 285 mAh g(-1) under the high current densities of 2 and 5 A g(-1), respectively. Moreover, ex situ X-ray diffraction and X-ray photoelectron spectroscopy are utilized to examine the phase evolution and valence changes during the first lithiated process. A small amount of inserted Li(+) induces a decomposition of LiVMoO6 into Li2Mo2O7 and V2O5, which play the host during further lithiated processes. When being discharged to 0.01 V, most V(5+) change into V(3+)/V(2+), suggesting intercalation/deintercalation processes, whereas Mo(6+) are reduced into a metallic state on the basis of the conversion reaction. The insights obtained from this study will benefit the design of novel anode materials for lithium-ion batteries.
采用简便的液相法制备了钛铀矿型钒钼氧化物LiVMoO6,并通过恒电流充放电曲线、倍率性能和循环伏安法对其作为锂离子电池负极的电化学性能进行了全面研究。在3.0至0.01 V的工作电压范围内,LiVMoO6在100 mA g(-1)的电流密度下具有超过900 mAh g(-1)的高可逆容量,并且在2和5 A g(-1)的高电流密度下分别具有约584和285 mAh g(-1)的优异倍率性能。此外,利用非原位X射线衍射和X射线光电子能谱研究了首次锂化过程中的相演变和价态变化。少量插入的Li(+)会导致LiVMoO6分解为Li2Mo2O7和V2O5,它们在进一步的锂化过程中充当主体。当放电至0.01 V时,大多数V(5+)转变为V(3+)/V(2+),表明存在嵌入/脱嵌过程,而基于转化反应,Mo(6+)被还原为金属态。本研究获得的见解将有助于锂离子电池新型负极材料的设计。