Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (7): 1699-1707.doi: 10.3866/PKU.WHXB201604011

• ARTICLE • Previous Articles     Next Articles

Effects of Structure on Electrochemical Performances of Ribbon-Shaped Mesophase Pitch-Based Graphite Fibers

Jia-Jun HUANG1,2,Zhi-Jun DONG1,2,*(),Xu ZHANG1,2,Guan-Ming YUAN1,2,Ye CONG1,2,Zheng-Wei CUI1,Xuan-Ke LI1,2,3,*()   

  1. 1 The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, P. R. China
    2 Hubei Province Key Laboratory of Coal Conversion and New Materials, Wuhan University of Science and Technology, Wuhan 430081, P. R. China
    3 The Research Center for Advanced Carbon Materials, Hunan University, Changsha 410082, P. R. China
  • Received:2016-01-11 Published:2016-07-08
  • Contact: Zhi-Jun DONG,Xuan-Ke LI E-mail:dongzj72@sohu.com;xkli8524@sina.com
  • Supported by:
    the National Natural Science Foundation of China(91016003);National Natural Science Foundation of China(51372177);National Natural Science Foundation of China(51352001);National Natural Science Foundation of China(51472186)

Abstract:

Ribbon-shaped mesophase pitch-based graphite fibers (MPGFs) were prepared by melt-spinning, preoxidation, carbonization, and graphitization. The effects of the size of the spinneret and spinning rate on the orientation of the carbon layers and crystal structure of the ribbon-shaped graphite fibers transverse section were investigated. The electrochemical performances of the ribbon-shaped MPGFs as anode materials for lithium-ion batteries were tested. The results show that the size of the spinneret and spinning rate significantly affect the orientation of the carbon layers. The carbon layers of graphite fibers that were prepared at a low spinning rate using a spinneret with a low length/width ratio were arranged along the radial direction. These fibers had good rate capability. Their discharge specific capacities at 0.1C and 1C rates were 336 and 300 mAh·g-1, respectively. However, the fibers showed poor cyclic performance. After 100 cycles at 0.1C rate, the capacity retention was only 89.1%. The carbon layers of the graphite fibers that were prepared at a low spinning rate using a spinneret with a high length/width ratio had a wavy, wrinkled texture and were arranged along the direction parallel to the principal plane of the fibers. These fibers had poor rate capability and excellent cyclic performance. After 100 cycles at 0.1C rate, the capacity retention was 98.8%. Meanwhile, an increase in the spinning rate causes an overall decrease in the order degree of the carbon layers of the graphite fibers, and results in a decrease of the carbon layers being arranged along the direction parallel to the principal plane of the fibers. Both these factors decrease the reversible specific capacity.

Key words: Mesophase pitch, Ribbon-shaped graphite fiber, Orientation of carbon layers, Anode materials, Cyclic performance

MSC2000: 

  • O646