Inorganic Chemicals Industry ›› 2022, Vol. 54 ›› Issue (12): 68-73.doi: 10.19964/j.issn.1006-4990.2022-0135

• Research & Development • Previous Articles     Next Articles

Effect of ball milling time on electrochemical properties of graphene composites

MA Caifu1(),YUAN Chuanlai2,ZHAO Xueqi3   

  1. 1. Hunan Communication Polytechnic, Changsha 410015, China
    2. Hunan University of Technology
    3. Guangdong University of Technology
  • Received:2022-04-22 Online:2022-12-10 Published:2022-12-19

Abstract:

The effects of ball milling time on the microstructure and electrochemical properties of graphene/La15Fe2Ni71Mn6B2Al2 composites were studied by means of X-ray diffraction(XRD),scanning electron microscope(SEM) and electrochemical workstation.The results showed that the graphene composite hydrogen storage alloys milled for 0~60 min were mainly composed of La3Ni13B2,(Fe,Ni) and LaNi5 phases,and the cell volume of LaNi5 phase would decrease with the increase of milling time.With the increase of ball milling time from 0 to 60 min,the charge transfer resistance of graphene composite hydrogen storage alloy was firstly decreased and then increased,the exchange current density was firstly increased and then decreased,the hydrogen diffusion coefficient and charge retention were firstly increased and then decreased.When the ball milling time was 40 min,the minimum value of charge transfer resistance and the maximum value of exchange current density,hydrogen diffusion coefficient and charge retention were obtained.In addition,graphene composite hydrogen storage alloys showed relatively high discharge capacity at the same cycle times and ball milling time of 40 min.The suitable milling time of graphene/La15Fe2Ni71Mn6B2Al2 composite was 40 min,and the hydrogen diffusion coefficient and charge retention were 1.259×10-8 cm2/s and 97.62% respectively,which showed good electrochemical properties.It was mainly related to the fine and uniform powder particles and high crystallinity of the composite.

Key words: ball milling time, graphene, hydrogen storage alloy, microstructure, electrochemical performance

CLC Number: