H.Y. Zhou

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

The structure and electrochemical properties of La0.8–xCexPr0.1Nd0.1B5 (B5 ≡ Ni3.8Co1.1Mn0.1; 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 La0.8‒xCexPr0.1Nd0.1B5 alloy electrodes are also improved by increasing Ce content.

The isothermal section of the Tb–Co–Cr ternary system at 873 K

The isothermal section of the phase diagram of the Tb–Co–Cr ternary system at 873 K was investigated by means of X-ray diffraction, metallography, and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy. Ternary phases and their lattice parameters as a function of composition of solid solution were systematically studied. The existence of one ternary phase reported previously was confirmed. The ternary compound Tb(Co, Cr)12 crystallizes with ThMn12-type structure, space group I4/mmm. The linear homogeneity range along the line of 7.69 at.% Tb in TbCo12− x Cr x was found to be about x = 3.6–5.7, i.e., 27.7–43.8 at.% Cr. The lattice parameters are a = 0.8326–0.8352 nm and c = 0.4709–0.4740 nm. The maximum solid solubilities of Cr in Tb2Co17, TbCo3, and TbCo2 are about 20.0, 8.2, and 7.9 at.%, respectively.