Nickel, Graphene, and Yttria-Stabilized Zirconia (YSZ)-Added Mg by Grinding in Hydrogen Atmosphere for Hydrogen Storage

Abstract

Magnesium (Mg) has good hydrogen storage features except for its slow reaction kinetics with hydrogen and high hydride decomposition temperature. Yttria (Y2O3)-stabilized zirconia (ZrO2) (YSZ), nickel (Ni), and graphene were picked as additives to Mg to solve these problems. Samples with a composition of 92.5 wt% Mg + 2.5 wt% YSZ + 2.5 wt% Ni + 2.5 wt% graphene (designated as Mg + YSZ + Ni + graphene) were prepared by grinding in hydrogen atmosphere. The activation of Mg + YSZ + Ni + graphene was finished at the third cycle (n = 3). Mg + YSZ + Ni + graphene had an efficient hydrogen storage capacity (the amount of hydrogen absorbed for 60 min) over 7 wt% (7.11 wt%) at n = 1. Mg + YSZ + Ni + graphene contained Mg2Ni phase after cycling. The addition of Ni and Ni + YSZ greatly increased the initial hydride formation and decomposition rates, and the amount of hydrogen absorbed and released for 60 min, Ha (60 min) and Hd (60 min), respectively, of a 95 wt% Mg + 5 wt% graphene sample (Mg + graphene). Rapid nucleation of the Mg2Ni-H solid solution in Ni-containing samples is believed to have led to higher initial decomposition rates than Mg + graphene and Mg. The addition of YSZ also enhanced the initial decomposition rate and Hd (60 min) compared to a sample with a composition of 95 wt% Mg + 2.5 wt% Ni + 2.5 wt% graphene (Mg + Ni + graphene).