What determines the critical size for phase separation in LiFePO_4 in lit hium ion battery?
What determines the critical size for phase separation in LiFePO_4 in lit hium ion battery?
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是什么决定了锂离子电池LiFePO_4相分离的临界尺寸？
DOI：
10.1039/c3ta13122j
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发表时间：
2013
影响因子：
11.9
通讯作者：
S. Okada and J. Yamaki
中科院分区：
文献类型：
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作者：
T. Ichitsubo;T. Doi;K. Tokuda;E. Matsubara;T. Kida;T. Kawaguchi;S. Yagi;S. Okada and J. Yamaki
LiFePO 4在Li离子电池中的充电/放电过程中由于两相（LiFePO 4/FePO 4）分离而特征性地显示出平台电压。在这项研究中，我们清楚地表明，单分散的纳米尺寸（约10 nm）的LiFePO 4颗粒表现出完整的单相反应，没有显示出任何平台电压。由于LiFePO 4和FePO 4之间的晶格失配引起的弹性应变在表面附近容易释放，因此通常预期弹性效应减弱，但是，与此预期相反，在这种小纳米颗粒中实验上不会发生相分离。仅基于静态热力学的考虑不足以解释为什么在纳米尺寸的颗粒中发生这种单相反应。相反，单相反应的机制可以自然地理解，当我们考虑一个动力学概念的基础上的优选波长的稳定增长的旋节波在这样的弹性约束。
LiFePO4 characteristically shows a plateau voltage due to a two-phase (LiFePO4/FePO4) separation during the charge/discharge process in Li ion batteries. In this study, we clearly show that monodispersed nano-sized (about 10 nm) LiFePO4 particles exhibit a complete single-phase reaction without showing any plateau voltage. Since the elastic strain due to lattice mismatch between LiFePO4 and FePO4 would be easily released near the surface, elastic effects are usually expected to weaken, but, in contrast to this expectation, phase separation does not occur experimentally in such small nanoparticles. Consideration on the basis of only static thermodynamics is insufficient to explain why such a single-phase reaction occurs in nano-sized particles. In contrast, the mechanism of the single-phase reaction can be naturally understood, when we consider a kinetics concept based on the preferred wavelength for stable growth of the spinodal wave under such an elastic constraint.