Abstract
Microwave solvothermally (MW-ST) synthesized crystalline nanopowders of LiFePO4 have been structurally characterized using a combination of high resolution powder neutron diffraction, synchrotron X-ray diffraction and HAADF STEM images. The presence of a significant level of defects has been verified for the samples prepared at 255 oC and 275 oC. These temperatures are significantly higher than what has previously been suggested to be the maximum temperature for defect formation in LiFePO4, and their presence likely relates to the rapid synthesis provided by the MW-ST approach. 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.
