Electrochemical properties of the CaNi _{5− x} Mn _x electrodes synthesized by mechanical alloying

Abstract

In this article, we exhaustively examined the effects of Mn substitution for Ni on the structures and electrochemical characterization of the CaNi 5−x Mn x (x = 0.2, 0.3, 0.5, 1) alloys prepared by mechanical synthesis for 40 hours at ball to powder weight ratio of 8:1. The characterization of electrodes was examined by X-ray diffraction, scanning electron microscope and electrochemical tests. In this context, the structural properties for each alloy have two major phases Ni, Ca 2 Ni 7 ; Ni, CaNi 3 ; Ni, CaNi 5 ; Ni, CaNi 3 where x = 0.2, 0.3, 0.5 and 1 respectively. The powder micrograph shows the existence of agglomerates has average particle size between 22 and 35 μm. In addition, the quantification by energy dispersive spectroscopy has been indicated the chemical composition of the all produced alloys is near their nominal composition. All electrodes are activated during the first cycle, independent of the Mn substitution rate. The highest values of discharge capacity and reversibility are obtained for x = 0.3 (125 mAh g −1 , 0.17 V) and x = 0.5 (119 mAh g −1 , 0.19 V) despite their low cycle stability. The evolution of D H /a 2 ratio and the I 0 exchange current density for the different Mn substitution rates is in accordance with that of the evolution of discharge capacities. The better kinetic properties is observed for x = 0.5 during electrochemical cycling.

Electrochemical properties of theCaNi4.8M0.2(MMg, Zn, and Mn) mechanical milling alloys used as anode materials in nickel‐metal hydride batteries

“…During milling, there was an amorphization phenomenon that increased until 40 h of milling and, then, turned into crystallization. On the other hand, the electrochemical study indicated that the best property and the highest discharge capacity were obtained at 40‐milling time and an electrolyte concentration of 6 M 71–73 . Based on this extensive study of CaNi 4.8 Mn 0.2 (2, 10, 20, 30, 40, 50, and 60 h), we will make a comparative study of CaNi 4.8 M 0.2 where M will be replaced by Mg, Zn, and Mn metals while keeping the same optimized parameters: milling time of 40 h, a ball to powder weight ratio equal to 8:1 and electrolyte concentration of 6 M. This manuscript presents a structural, morphological, and electrochemical characterization to examine the effect of CaNi 5 substitution by different metals Mg, Zn, and Mn.…”

Structure and electrochemical hydrogen storage properties of spinel ferritesSmxZn1−xFe2O4alloys (x = 0,x = 0.2,x = 0.4, andx = 0.6) forNi‐MHaccumulator applications

“…In recent years, many studies have been conducted to develop oxide-based materials [2][3][4][5][6][7][8][9] (nanotube vanadium oxide, perovskite, and so forth) and integrate them into the Ni-MH battery. With a more competitive electrochemical profile than that of some hydrides, [10][11][12][13][14] ferrites are alternative materials to hydrides.…”