Study on Microstructure and Electrochemical Properties of Mg1.6Ni1-xTi0.4Mnx (x = 0~0.3) Alloy

Mg2Ni hydrogen storage alloy has the advantages of large hydrogen storage per unit mass, low price, and abundant resources, but there are shortcomings such as activation difficulties and poor kinetic performance. This paper improves the performance of Mg2Ni hydrogen storage alloy by adding Ti and Mn alloying elements. Mg1.6Ni1-xTi0.4Mnx (x = 0~0.3) hydrogen storage alloys with different Mn contents were prepared by the solid phase diffusion method. The physical structure and microscopic morphology of the prepared alloys were characterized using XRD and SEM techniques, and their charge/discharge and electrochemical properties were tested using a battery tester and an electrochemical workstation. The results show that the solid phase diffusion reaction of the prepared alloys resulted in the formation of the Mg phase with a layered structure, a Mg2Ni hydrogen storage phase, and intermetallic compounds Ni3Ti and Mg3MnNi2 phases. The presence of Ni3Ti and Mg3MnNi2 phases improved the activation properties and discharge capacity of the alloys. The alloys with Mn addition all reached the maximum discharge capacity at the first cycle. The maximum discharge capacity increased from 50.45 mAh/g without Mn addition to 96.67 mAh/g at x = 0.3. The maximum discharge capacity of the alloy increased to 165.52 mAh/g at 323 K. The maximum discharge capacity of the alloy increased from 50.45 mAh/g without Mn addition to 96.67 mAh/g. And its corrosion current density was reduced from 0.96 mA/g without Mn addition to 0.3 mA/g.