Effect of Ce content on structure and electrochemical properties of La0.8–xCexPr0.1Nd0.1B5 (B = Ni, Co, Mn; 0 ⩽ x ⩽ 0.3) hydrogen storage alloys

Abstract

The structure and electrochemical properties of La_0.8–xCe_xPr_0.1Nd_0.1B₅ (B₅ ≡ Ni_3.8Co_1.1Mn_0.1; x = 0, 0.1, 0.2, 0.3) hydrogen storage alloys have been investigated. The results show that all alloys consist of CaCu₅-type single phase. The maximum discharge capacity of the alloy electrodes decreases from 368.7 mA h g^–1 (x = 0) to 294.9 mA h g^–1 (x = 0.30), the cyclic stability (S100) increases from 37.6% (x = 0) to 69.8% (x = 0.20) after 100 charge/discharge cycles, and the HRD1200 first increases from 69.5% (x = 0) to 85.2% (x = 0.20), then decreases to 80.8% (x = 0.30). Meanwhile, the electrochemical kinetic characteristics of the La_0.8‒xCe_xPr_0.1Nd_0.1B₅ alloy electrodes are also improved by increasing Ce content.