Hydrogen absorption–desorption features and degradation mechanism of ErNi3 compound

Abstract

Abstract The hydrogen absorption–desorption features and degradation mechanism of ErNi 3 compound are investigated in detail. It is fount that two plateaus exist in the P – C isotherms where the lower one corresponds to ErNi 3 H ∼1.3 and the higher one to ErNi 3 H ∼4 . Their enthalpy changes are −27.42 and−23.51 kJ/mol H 2 , respectively, in hydriding process. During hydrogen absorption–desorption cycles, however, ErNi 3 shows a bad cycling performance which is attributed to partial decomposition of ErNi 3 into ErNi 2 and ErNi 5 as well as increase of host-lattice strain due to the remained H atoms.