3D structural properties study on compact LiFePO4s based on X-ray computed tomography technique

• LiFePO4/C powders of four compacted densities were characterized with XCT.
• Pore distribution of all four powders is 3D presented.
• Some small isolated pores are observed among the large sizes of connected pores.
• Porosity decreased as the compact density increased.
• The percentage of small size pores increases with the increase of compact density.

X-ray computed tomography (XCT) technique has been used to image the three-dimensional structural properties of four different compact densities of LiFePO4/C (LFP/C). The LFP/C particles and pore morphology distribution are qualitatively and visually observed. The pores' structural properties such as porosity and pores size distribution have been analyzed and calculated with specific algorithm. The porosity of the LFP/C samples decreases as the increase of compact density. Meanwhile, the number percentage of the relatively small pores has a marked increase with the larger compact density. The influence of the varied compact density to the electrochemical properties of as-fabricated lithium ion battery (LIB) is also discussed, which is determined by the variation of pore structural properties based on the XCT results.

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