| Autor: |
Junling Zhang, Shumin Han, Yuan Li, Yifei Lv, Shuqin Yang, Jinding Wang, Jingjing Liu |
| Rok vydání: |
2013 |
| Předmět: |
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| Zdroj: |
Electrochimica Acta. 111:18-24 |
| ISSN: |
0013-4686 |
| DOI: |
10.1016/j.electacta.2013.07.227 |
| Popis: |
A novel method high-pressure sintering was applied to prepare La 0.25 Mg 0.75 Ni 3.5 alloy as negative electrode material for nickel/metal hydride battery. The phase structures, electrochemical performance and electrochemical kinetics of the alloys sintered with various pressures have been investigated. When sintered within 1.5–2.5 GPa, the alloys have Ce 2 Ni 7 -type and Pr 5 Co 19 -type main phases and LaNi 5 minor phase. Pressurizing promotes the formation of Ce 2 Ni 7 -type phase with higher crystalline density. But when the sintering pressure reaches 4 GPa, the atomic diffusion is hindered, leading to the rise of LaNi 5 phase, appearance of MgNi 2 phase, and decrease of Ce 2 Ni 7 -type and Pr 5 Co 19 -type phases. Electrochemical measurements show that when the sintering pressure changes from 1.5 to 4 GPa, the maximum discharge capacity first increases then decreases. The alloy electrode sintered at 2 GPa shows superior high rate dischargeability and the gentlest capacity decrease with increasing discharge current density. Furthermore, kinetic study demonstrates that the reaction of alloy electrodes is controlled by charge-transfer step. Cycling stability is deteriorated as the sintering pressure increases due to higher expansion ratio of the cell volume and denser structures of the alloy. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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