Acta Chim. Sinica ›› 2016, Vol. 74 ›› Issue (7): 582-586.DOI: 10.6023/A16030114 Previous Articles     Next Articles



张国彬, 熊腾飞, 潘雪雷, 晏梦雨, 韩春华, 麦立强   

  1. 材料复合新技术国家重点实验室 武汉理工大学材料科学与工程学院 武汉 430070
  • 投稿日期:2016-03-03 发布日期:2016-06-07
  • 通讯作者: 麦立强
  • 基金资助:


In Situ Observation and Mechanism Investigation of Lattice Breathing in Vanadium Oxide Cathode

Zhang Guobin, Xiong Tengfei, Pan Xuelei, Yan Mengyu, Han Chunhua, Mai Liqiang   

  1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070
  • Received:2016-03-03 Published:2016-06-07
  • Supported by:

    Project supported by the International Science & Technology Cooperation Program of China (No. 2013DFA50840), the National Science Fund for Distinguished Young Scholars (No. 51425204) and the National Basic Research Program of China (Nos. 2013CB934103, 2012CB933003).

As cathode materials in lithium-ion batteries, layered vanadium oxides have been extensively studied and used in many aspects varying from industrial production to our daily life, due to their excellent physical property and gorgeous lithium storage performance. During lithiation/delithiation, layered vanadium oxides such as V2O5 xerogel (with a bilayer structure), undergoes "lattice breathing" which leads to the deactivation of electrode materials and fast capacity fading, which limits its large-scale application. In this work, VOx is used as the cathode material of lithium-ion batteries to study the "lattice breathing" phenomenon. The phase evolution has been observed and studied via in situ method. The X-ray diffraction (XRD) patterns show typical (001) diffraction peaks characteristic of vanadium oxide xerogel structure and also confirm the good crystallinity. This compound with crystal parameters of a=4.56 Å, b=14.87 Å, c=12.38 Å, α=117.26°, β=96.02°, γ=81.86°, forms a triclinic structure. Results of scanning electron microscope (SEM) and transmission electron microscope (TEM) further verify the layered structure of VOx. The thermo gravimetric analysis (TGA) at air and nitrogen atmosphere shows that the carbon content of the sample is about 2.4 wt% and the water content is about 2.1%. As lithium-ion battery cathode the initial discharge capacity of the compound is about 136 mA·h/g at a current density of 100 mA/g, with a capacity retention of 92.6% after 50 cycles. To study the lithium storage mechanism of VOx, electrochemical discharge/charge processes are further investigated by in situ XRD. It is found that the lattice plane diffraction displays three different stages linked during the insertion and deinsertion of lithium ions, indicating three solid solution reactions. During discharge process, the three diffraction changes show continuous shifts to higher diffraction angles, demonstrating three different continuous contraction processes with the insertion of lithium ions. Nevertheless, the evolution of the (001) peak is swift during the beginning and the end of discharge, in contrast to the slow deviation of the intermediate process. In the whole process, the diffraction pattern displays periodic changes, confirming the reversibility of the reaction process. The corresponding calculations of d001 during the discharge/charge process prove the notable discontinuity between these three stages. In addition, cycling experiments conducted at the higher and the lower temperature indicate that the electrochemical performance of this compound is highly sensitive to temperature.

Key words: lithium-ion battery, cathode material, layered vanadium oxides, in situ, phase transition