Defect chemistry of phospho-olivine nanoparticles synthesized by a microwave-assisted solvothermal process

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• 作者：Craig A. Bridges ; Katharine L. Harrison ; Raymond R. Unocic ; Juan-Carlos Idrobo ; M. Parans Paranthaman ; Arumugam Manthiram
• 关键词：Lithium-ion batteries ; LiFePO4 cathode ; Antisite disorder ; Neutron diffraction
• 刊名：Journal of Solid State Chemistry
• 出版年：2013
• 出版时间：September, 2013
• 年：2013
• 卷：205
• 期：Complete
• 页码：197-204
• 全文大小：2274 K

文摘

Nanocrystalline LiFePO₄ powders synthesized by a microwave-assisted solvothermal (MW-ST) process have been structurally characterized with a combination of high resolution powder neutron diffraction, synchrotron X-ray diffraction, and aberration-corrected HAADF STEM imaging. A significant level of defects has been found in the samples prepared at 255 and 275 ¡ãC. These temperatures are significantly higher than what has previously been suggested to be the maximum temperature for defect formation in LiFePO₄, so the presence of defects is likely related to the rapid MW-ST synthesis involving a short reaction time (¡«5 min). A defect model has been tentatively proposed, though it has been shown that powder diffraction data alone cannot conclusively determine the precise defect distribution in LiFePO₄ samples. The model is consistent with other literature reports on nanopowders synthesized at low temperatures, in which the unit cell volume is significantly reduced relative to defect-free, micron-sized LiFePO₄ powders.