Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6612419 | Electrochimica Acta | 2015 | 9 Pages |
Abstract
To determine the structure and electrochemical properties of La-Mg-Ni-based Pr5Co19-type super-stacking structure alloys, a La0.84Mg0.16Ni3.80 alloy was designed and synthesized by step-wise powder sintering. X-ray diffraction (XRD) analysis and Rietveld refinement show that the alloy consists of a single Pr5Co19-type phase. Electrochemical studies show that the alloy has a mediocre discharge capacity of 338 mAh gâ1 and good cycling stability. High rate dischargeability at 1500 mA gâ1(HRD1500) reaches 51.5% and the corresponding discharge capacity remains 174 mAh gâ1. To improve overall electrochemical properties of the alloy, especially the discharge capacity, Ce2Ni7-type or LaNi5 secondary phase was introduced into the single-phase alloy by adjusting molar ratio of precursors. When the content of Ce2Ni7-type phase increases from 0 to 40.6 wt.%, the maximum discharge capacity enhances from 338 to 388 mAh gâ1 and the discharge capacity retention at the 100th cycle is improved from 77.0% to 85.3%. With the presence of 20.7 wt.% LaNi5 phase in the alloy, the HRD1500 increases to 56% and the surface exchange current density (i0) increases from 275.50 mA gâ1 to 354.16 mA gâ1.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Yumeng Zhao, Shumin Han, Yuan Li, Jingjing Liu, Lu Zhang, Shuqin Yang, Dandan Ke,