Precursor‐Directed Nucleation and Self‐Assembly Growth: From Hollow Microprisms to Nanoplatelets

Abstract Directly controlling the morphology and orientation of nanocrystals is a key step for their tailored applications. Achieving such controlled synthesis requires insight into the formation mechanism. Using Li₃PO₄ microprisms as a solid precursor sealed in capillary tube, we unravel the structural and morphological evolution from the precursor to the resultant LiFePO₄ nanoplatelets by means of in situ temperature monitoring, ex situ Raman spectroscopy and TEM/STEM. Under water‐deficient conditions, the precursor dissolves in a sluggish manner, facilitating simultaneous heterogeneous nucleation of LiFePO₄ on undissolved Li₃PO₄ and homogeneous nucleation in solution. Vertically aligned nanoribbons consisting of primary LiFePO₄ particles on the Li₃PO₄ surface undergo self‐assembly growth though oriented attachment. The [100]‐orientation is explained by the fact that H₃O⁺ preferably adsorbed on the LiFePO₄ (100) facet and suppressed the crystal growth more along the [100] direction than the others.