Nano-layered LiFePO4 particles converted from nano-layered ferrous phenylphosphonate templates

A new type of nano-structured LiFePO4 particles were prepared exhibiting enhanced apparent lithium ion diffusion dynamics. The nano-structured LiFePO4 particles possess nano-layered morphology and were converted hydrothermally from the nano-layered templates composed of mainly ferrous metaphosphate and graphitic carbon. And the nano-layered templates were prepared by pyrolysis conversion of the nano-layered ferrous phenylphosphonate templates, or the raw nano-layered templates. Though the nano-layered LiFePO4 particles possess characteristics of nanostructured LiFePO4, the overall dimensions are still in micro-size and the tap density is about 1.36 g cm−3 comparable to the micro-sized LiFePO4 particles. The apparent lithium ion diffusion coefficients are 1.5 × 10−11 and 3.1 × 10−13 cm2 s−1 evaluated using the cyclic voltammetry and electrical impedance spectroscopy, respectively. In addition, the organic moiety from the raw nano-layered templates was converted into tiny carbon particles with abundance of ordered graphitic structure well dispersed in the nano-layered LiFePO4 particles; and the nano-layered LiFePO4 particles possess an electronic conductivity as high as 3.28 mS cm−1.

The apparent Li+ diffusion coefficient D is enhanced by the nano-layered morphology of the LiFePO4 because of the abundant phase boundaries between the nano-layers.Figure optionsDownload as PowerPoint slideHighlights
► Nano-layered LiFePO4 particles are fabricated.
► The nano-layered LiFePO4 particles are converted from nano-templates.
► The lithium ion diffusion dynamics is enhanced.
► The lithium diffusion coefficient is 3.1 × 10−13 cm2 s−1.