Electrochemical hydrogen storage properties of TixV65−xNi35 (x=45, 55) alloys produced by rapid-quenching

Abstract

Electrochemical discharge performances of TixV65−xNi35 (x=45, 55) alloy are measured by electrochemical measurements at galvanostatic conditions, and alloy ribbon is prepared by rapid-quenching under argon atmosphere. XRD analysis of TixV65−xNi35 (x=45) alloy shows that the Ti45V20Ni35 (x=45) is mostly the amorphous phase, V-based solid solution phase with BCC structure phase and a negligible amount of (Ni, V) phase. While x=55, namely the Ti55V10Ni35 alloy, mainly consists of the icosahedral quasicrystal (I-phase), face centered cubic (FCC) phase with Ti2Ni-type structure and V-based solid solution phase with BCC structure phase. In the electrochemical tests, the maximum discharge capacity of Ti45V20Ni35 is about 150.4mAh/g at a current density of 30mA/g. However, Ti55V10Ni35 alloy shows that the best discharge capacity is 221.8mAh/g under the same condition. In addition, it exhibits extraordinary cycling stability of 87.2% at 30 charge–discharge cycles. It can be found that the discharge capacity of the amorphous electrode is lower than those of the I-phase ones under the similar composition levels.