Qian LI
,
Qin LIN
,
Lijun JIANG
,
Guozhi ZHOU
,
Feng ZHAN
,
Qiang ZHENG
材料科学技术（英）
A high activity and large capacity of hydrogen storage alloy Mg2Ni by hydriding combustion synthesis was investigated by means of pressure composition isotherms, X-ray diffraction and scanning electron microscopy. The results showed that the maximum hydrogen absorption capacity of Mg2Ni is 3.25 mass fraction at 523 K, just after synthesis without any activation. The relationships between the equilibrium plateau pressure and the temperature for Mg2Ni were lgp (0.1 MPa)=-3026/T+5.814 (523 K≤T ≤623 K) for hydriding and lgp (0.1 MPa)=-3613/T+6.715 (523 K≤T ≤623 K) for dehydriding. The kinetic equation is [-ln(1-α)]3/2 = kt and the apparent activation energy for the nucleation and growth-controlled hydrogen absorption and desorption were determined to be 64.3±2.31 kJ/(mol·H2) and 59.9±2.99 kJ/(mol·H2) respectively.
关键词:
Hydriding combustion
,
null
,
null
,
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Xianxia YUAN
,
Yindong WANG
,
Feng ZHAN
材料科学技术（英）
Effects of various Co species added by mechanically mixing with Ni(OH)(2) on the performance of Ni electrode were studied and the results were interpreted by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that CoO, Co and CoO+Co all can improve the performance of Ni electrode to some extent and the effect of CoO was the most obvious. This could be attributed to several causes: all three forms of additives increased the reversibility of Ni(II)/Ni(III) redox reaction, enhanced the oxygen evolution polarization, improved the charging efficiency of Ni electrode, improved the lattice imperfection of Ni hydroxide and made it more beneficial to charge transfer and H+ diffusion processes.
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