A general solution-chemistry route to the synthesis Li MPO 4 ( M=Mn, Fe, and Co) nanocrystals with [010] orientation for lithium ion batteries

Abstract

A general and efficient solvothermal strategy has been developed for the preparation of lithium transition metal phosphate microstructures (LiMnPO 4, LiFePO 4, and LiCoPO 4), employing ethanol as the solvent, LiI as the Li source, metal salts as the M sources, H 3PO 4 as the phosphorus source, and poly(vinyl pyrrolidone) (PVP) as the carbon source and template. This route features low cost, environmental benign, and one-step process for the cathode material production of Li-ion batteries without any complicated experimental setups and sophisticated operations. The as-synthesized Li MPO 4 microstructures exhibit unique, well-shaped and favorable structures, which are self-assembled from microplates or microrods. The b axis is the preferred crystal growth orientation of the products, resulting in a shorter lithium ion diffusion path. The LiFePO 4 microstructures show an excellent cycling stability without capacity fading up to 50 cycles when they are used as a cathode material in lithium-ion batteries.