Effects of Magnesium Content on Structure and Electrochemical Properties of La-Mg-Pr-Al-Mn-Co-Ni Hydrogen Storage Alloys

Table 5

The characteristics of alloy phases in the La_0.7−xMg_xPr_0.3Al_0.3Mn_0.4Co_0.5Ni_3.8 (x = 0.0–0.7) alloys.

Samples	Phases	Space group	Parameters of fit^a	Phase abundance (wt.%)	Lattice parameter (Ǻ)		Cell volume (Ǻ^3)
					a	c
x = 0.0	LaNi5	P6/mmm	Rp = 0.2660	74.2	5.047	4.063	89.6 ± 0.5
	PrNi5	P6/mmm	Rwp = 0.4664,  = 2.757	25.8	5.034	4.034	88.5 ± 0.5
x = 0.1	LaNi5	P6/mmm	Rp = 0.2416	43.0	5.017	4.062	88.5 ± 0.5
	PrNi5	P6/mmm	Rwp = 0.4440,  = 2.467	45.5	5.020	4.019	87.7 ± 0.5
	(La,Pr)Mg2Ni9	R-3m		11.5	4.950	24.299	516 ± 1
x = 0.3	(La,Pr)Ni5	P6/mmm	Rp = 0.2416	60.7	4.996	4.051	87.6 ± 0.5
	(La,Pr)Mg2Ni9	R-3m	Rwp = 0.4440,  = 2.467	29.3	4.936	24.104	509 ± 1
	AlMnNi6	Pm3m		10.0	3.603	3.603	46.8 ± 0.5
x = 0.5	(La,Pr)Ni5	P6/mmm	Rp = 0.2469	32.6	4.981	4.041	86.8 ± 0.5
	(La,Pr)Mg2Ni9	R-3m	Rwp = 0.6088,  = 2.148	42.6	4.932	23.993	505 ± 1
	AlMnNi6	Pm3m		24.8	3.590	3.590	46.3 ± 0.5
x = 0.7	PrNi5	P6/mmm	Rp = 0.2056	5.8	4.943	4.028	85.2 ± 0.5
	PrMg2Ni9	R-3m	Rwp = 0.3734,  = 2.249	46.4	4.918	23.906	501 ± 1
	AlMnNi6	Pm3m		33.5	3.583	3.583	46.0 ± 0.5
	MgNi2	P63/mmc		14.3	4.834	15.824	320 ± 1

^aR_p = pattern factor; R_wp = weighted pattern factor;  = goodness of fit.