Correlation between electrochemical behavior and hydrogen storage properties of Li-Sn system
Correlation between electrochemical behavior and hydrogen storage properties of Li-Sn system
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Li-Sn体系电化学行为与储氢性能的相关性
DOI：
10.1016/j.jallcom.2013.03.150
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发表时间：
2013
影响因子：
6.2
通讯作者：
Yoshitsugu Kojima
中科院分区：
文献类型：
--
作者：
Ankur Jain;Hiroki Miyaoka;Takayuki Ichikawa;Yoshitsugu Kojima
氢化锂的高稳定性是其作为储氢材料的瓶颈。本文是一个努力，以不稳定的Sn作为掺杂剂。选择Li4.4Sn是由于其在所有可能的化学计量中的最高锂含量。结果表明，样品的真实的组成是Li 17 Sn 4，而不是Li 4.4Sn。加氢反应的测定表明存在两步反应。Li 17 Sn 4首先与氢气反应生成LiH和Li 13 Sn 5的混合物，在所研究的加氢条件下，LiH和LiSn的混合物进一步转化为LiH和LiSn的混合相。第一步和第二步反应的焓值分别为−93 ± 11 kJ/mol H2和−37 ± 2 kJ/mol H2。这些值远低于纯LiH观察到的值。最后，这些氢化性质用于计算锂化/脱锂所需的电化学电势值。结果表明，Li-Sn体系的第一步和第二步反应的电位分别为0.456V和0.746V，与直接电化学方法计算的结果吻合较好。
The high stability of Lithium hydride is a bottleneck to use it as hydrogen storage media. The present paper is an effort to destabilize it using Sn as a dopant. Li4.4Sn is chosen due to its highest lithium content among all the possible stoichiometries. It is found that the real composition is Li17Sn4rather than Li4.4Sn. Hydrogenation measurements suggest the existence of two step reaction. Li17Sn4first react with hydrogen to form a mixture of LiH and Li13Sn5, which further transformed into a mixed phase of LiSn and LiH as final product under studied hydrogenation condition. The enthalpy values for the above mentioned reactions are found to be −93 ± 11 kJ/mol H2and −37 ± 2 kJ/mol H2for 1st and 2nd step respectively. These values are much lower than the values observed for pure LiH. Finally these hydrogenation properties were used to calculate the electrochemical potential values required for lithiation/delithiation. The value for potential for 1st step and 2nd step reaction is found to be 0.456 V and 0.746 V for Li–Sn system, which is in good agreement with the values calculated through direct electrochemical methods.