Particle size dependent confinement and lattice strain effects in LiFePO4.
Particle size dependent confinement and lattice strain effects in LiFePO4.
复制标题
LiFePO4 中粒径相关的限制和晶格应变效应。
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
S. Murugavel
中科院分区：
文献类型：
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作者：
R. Shahid;S. Murugavel
报道了用宽带阻抗谱和漫反射光谱测量不同粒径的LiFePO4(LFP)的本征电子性质。随着颗粒尺寸的减小(最大为150 nm)，其电学性质表现出典型的尺寸效应。然而，在纳米尺度上，我们观察到极化子电导率增加了大约一个数量级。我们发现，LFP中电子电导增强的原因是与颗粒尺寸减小相关的显著晶格应变。观察到的晶格应变分量对应于压缩部分，这导致极化子的跳跃长度减小。我们再现了LFP输运性质随粒子大小的非线性，以捕捉限制和晶格应变之间的相互作用，并跟踪应变对电子-声子相互作用的影响。这些结果可以解释为什么纳米LFP比体相LFP具有更好的放电容量和更高的倍率能力。我们认为，这些新的关联将为LFP作为先进锂离子电池正极材料的优化带来更多的洞察力和更好的理解。
We report the intrinsic electronic properties of LiFePO4 (LFP) with different particle sizes measured by broad-band impedance spectroscopy and diffuse reflectance spectroscopy. The electronic properties show typical size-dependent effects with decreasing particle size (up to 150 nm). However, at the nanoscale level, we observed an enhancement in the polaronic conductivity about an order of magnitude. We found that the origin of the enhanced electronic conductivity in LFP is due to the significant lattice strain associated with the reduction of particle size. The observed lattice strain component corresponds to the compressive part which leads to a decrease in the hopping length of the polarons. We reproduce nonlinearities in the transport properties of LFP with particle size, to capture the interplay between confinement and lattice strain, and track the effects of strain on the electron-phonon interactions. These results could explain why nano-sized LFP has a better discharge capacity and higher rate capability than the bulk counterpart. We suggest that these new correlations will bring greater insight and better understanding for the optimization of LFP as a cathode material for advanced lithium ion batteries.
影响因子：
8.6
作者：
Rata, A. D.;Herklotz, A.;Doerr, K.
通讯作者：
Doerr, K.