Storage performance of LiFePO4 nanoplates

Abstract

The morphology of electrode materials is addressed as a key factor controlling rapid lithium storage in anisotropic systems such as LiFePO₄. In view of this, we have synthesized nanoplates of LiFePO₄ with a uniform coating of a 5 nm thick amorphous carbon layer by the solvothermal method and investigated their electrochemical storage behavior. The obtained nanoplates are well characterized by XRPD, SEM, HRTEM and XPS techniques. The thickness along the b-axis is found to be 30–40 nm; such a morphology favors short diffusion lengths for Li⁺ ions, while the external conductive carbon coating provides connectivity for facile electron diffusion, resulting in high rate performances. Increase in the size of the nanoplates results in poor lithium storage performance. The storage performance of nanoplates is compared with that of mesoporous nanoparticles of LiFePO₄ with non-uniform carbon coating. This paper thus describes the advantages of thinner nanoplates for high rate storage performances of battery electrode materials.