Effect of TiMn1.5 alloying on the structure,hydrogen storage properties and electrochemical properties of LaNi3.8Co1.1Mn0.1 hydrogen storage alloys

A series of experiments were performed to investigate the effect of TiMn_1.5 alloying on the structure, hydrogen storage properties and electrochemical properties of LaNi_3.8Co_1.1Mn_0.1 hydrogen storage alloys at 303 K. For simple, A, B, and C are used to represent alloys (x = 0 wt %, x = 4 wt % and x = 8 wt %) respectively. The results of XRD and SEM show that LaNi_3.8Co_1.1Mn_0.1?xTiMn_1.5 hydrogen storage alloys have LaNi₅ phase and (NiCo)₃Ti phase. Based on the results of PCT curves, the hydrogen storage capacities of LaNi_3.8Co_1.1Mn_0.1?xTiMn_1.5 hydrogen storage alloys are about 1.28 wt % (A), 1.16 wt % (B) and 1.01 wt % (C) at 303 K. And the released pressure platform and the pressure hysteresis decrease with the increase of TiMn_1.5 content. Meanwhile the activation curves show that LaNi_3.8Co_1.1Mn_0.1?xTiMn_1.5 hydrogen storage alloy electrodes can be activated in three times and the maximum discharge capacity is 343.74 mA h/g at 303 K. In addition, with the increase of TiMn_1.5 content, the cyclic stability of the hydrogen storage alloy electrodes decreases obviously and the capacity retention decreases from 76.70% to 70.00% when TiMn_1.5 content increases from A to C. It also can be seen that LaNi_3.8Co_1.1Mn_0.1?xTiMn_1.5 hydrogen storage alloy electrode C and B have the best self-discharge ability and the best high-rate discharge ability from self-discharge curves and high-rate discharge curves.