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Shape Matters: The Effect of Particle Morphology on the Fast-Charging Performance of LiFePO₄/C Nanoparticle Composite Electrodes.

ABSTRACT: For the successful use of lithium-ion batteries in automotive applications, reliable availability of high storage capacity and very short recharging times are essential. In order to develop the perfect battery for a certain application, structure-property relationships of each active material must be fully understood. LiFePO₄ is of great interest due to its fast-charging capability and high stability regarding its thermal resistance and chemical reactivity. The anisotropic lithium-ion diffusion through the LiFePO₄ crystal structure indicates a strong dependence of the electrochemical performance of a nanostructured active material on particle morphology. In this paper, the relationship of the particle morphology and fast-charging capability of LiFePO₄/C core/shell nanoparticles in half-cells was studied. For this purpose, a new multistep synthesis strategy was developed. It involves the combination of a solvothermal synthesis followed by an in situ polymer coating and thermal calcination step. Monodisperse rodlike LiFePO₄ nanoparticles with comparable elongation along the b-axis (30-50 nm) and a varying aspect ratio c/a (2.4-6.9) were obtained. A strong correlation of the fast-charging capability with the aspect ratio c/a was observed. When using LiFePO₄ nanoparticles with the smallest aspect ratio c/a, the best electrochemical performance was received regarding the specific capacity at high C-rates and the cycling stability. A reduction of the aspect ratio c/a by 30% (3.6 to 2.4) was found to enhance the charge capacity at 10 C up to an order of magnitude (7.4-73 mA h·g^-1).

SUBMITTER: Seher J

PROVIDER: S-EPMC8459431 | biostudies-literature |

REPOSITORIES: biostudies-literature

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