Lithium Tracer Diffusion in Amorphous LixSi for Low Li Concentrations
Lithium Tracer Diffusion in Amorphous LixSi for Low Li Concentrations
复制标题
低锂浓度下非晶 LixSi 中的锂示踪扩散
DOI：
10.1021/acs.jpcc.7b12296
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发表时间：
2018
影响因子：
3.7
通讯作者：
H. Schmidt
中科院分区：
文献类型：
--
作者：
F. Strauß;L. Dörrer;M. Bruns;H. Schmidt
研究了锂离子电池负极材料非晶态锂硅化合物中Li示踪剂的自扩散行为。利用二次离子质谱仪对LixSi/6LixSi(LixSi，x∼0.02和x∼0.06)薄膜异质结进行了实验研究。在140~325℃温度范围内，扩散系数服从阿累尼乌斯定律，其活化能均为(1.42±0.03)eV，而富Li样品的扩散系数高一个数量级。提出了陷阱限制扩散机制，并用较低浓度的不饱和陷阱解释了这一结果。与文献相反的讨论表明，锂浓度对扩散系数有很强的依赖关系，对于较高的x也是如此。
Li tracer self-diffusion was studied in amorphous lithium–silicon compounds which are important as negative electrodes in Li-ion batteries. Experiments were done on LixSi/6LixSi (LixSi,x∼ 0.02 andx∼ 0.06) thin-film heterostructures using secondary ion mass spectrometry. The diffusivities follow the Arrhenius law in the temperature range between 140 and 325 °C, both with an activation energy of (1.42 ± 0.03) eV, while the Li-richer samples show 1 order of magnitude higher diffusivities. A trap-limited diffusion mechanism is suggested, explaining this result with a lower concentration of unsaturated traps. A discussion against the literature suggests a strong lithium concentration dependence of diffusivities also for higherx.