Electrochemical Lithiation of Silicon Clathrate-II
Electrochemical Lithiation of Silicon Clathrate-II
复制标题
硅笼形物-II的电化学锂化
DOI：
10.1149/2.082208jes
复制
发表时间：
2012
影响因子：
3.9
通讯作者：
M. Winter
中科院分区：
文献类型：
--
作者：
T. Langer;Sven Dupke;H. Trill;S. Passerini;H. Eckert;R. Pöttgen;M. Winter
通过从ZnTl相NaSi中提取钠，合成了笼形II化合物NaxSi 136（x→ 0）作为电化学锂化的前驱体。通过Rietveld精修确定最终组成为Na 1.3 Si 136。该笼形物-II化合物的电化学锂化在300 mV下产生电位平台，其容量与插入笼形物-II结构中的24个锂原子良好一致。为了证明这一假设，制备了几种含笼形物的电极并进行电化学锂化。然后使用7 Li魔角旋转（MAS）-NMR光谱研究电极材料。2中的两个信号：1的比率，分别在412和433 ppm的极高的化学位移，相对于1 M氯化锂水溶液，被检测到，并给出无可争议的证据，锂化的笼形化合物-II框架是成功的。因此，这项工作提出了一种新的方法来填充笼形物，而且，第一个含锂笼形化合物。
The clathrate-II compound Na x Si 136 (x→ 0) was synthesized as a precursor for electrochemical lithiation via sodium extraction from the Zintl-Phase NaSi. The final composition was determined to be Na 1.3 Si 136 via a Rietveld refinement. Electrochemical lithiation of this clathrate-II compound yielded a potential plateau at 300 mV whose capacity is in good agreement with 24 lithium atoms being inserted in the clathrate-II structure. In order to prove this assumption, several clathrate-containing electrodes were prepared and electrochemically lithiated. Afterwards the electrode material was investigated using 7 Li magic-angle spinning (MAS)-NMR spectroscopy. Two signals in a 2: 1 ratio at extremely high chemical shifts of 412 and 433 ppm, respectively, relative to 1M aqueous lithium chloride solution, were detected and give the indisputable evidence that lithiation of the clathrate-II framework was successful. Hence, this work presents a new method for filling clathrate cages and moreover, the first lithium containing clathrate compound.