Structure and electrochemical property of ball-milled Ti0.26Zr0.07Mn0.1Ni0.33V0.24 alloy with 3 mass% B

Abstract

The high-energy ball-milling technique is generally used to modify the surface structure and texture of materials in order to improve their physical or chemical properties. Ti0.26Zr0.07Mn0.1Ni0.33V0.24 alloy was ball-milled with 3 mass% B. Microstructure of Ti0.26Zr0.07Mn0.1Ni0.33V0.24-3 mass% B hydrogen storage electrode alloys have been investigated using XRD, FESEM–EDS and EIS measurements. The ball-milled alloys are composed of V-based solid solution phase and C14 Laves phase. It is indicated that the ball-milling with B did not influence the bulk crystal structure of the Ti0.26Zr0.07Mn0.1Ni0.33V0.24 alloy. The ball-milling with B greatly decreased the maximum discharge capacity of the powder electrodes, but the cyclic stability of the ball-milled alloys is noticeably improved. The capacity retention rate after 45 cycles increases from 42% (t = 20 min) to 63.9% (t = 90 min). The high-rate dischargeability at the discharge current density of 600 mA g−1 increases from 45.6% (t = 20 min) to 59.7% (t = 90 min).The improvement in electrochemical kinetic properties of the ball-milled alloys should be ascribed to the increasing the exchange current density and hydrogen diffusion coefficient.