Continuous solid-phase synthesis of nanostructured lithium iron phosphate powders in air

摘要

In this study, a cathode material based on LiFePO4/C is synthesised directly via continuous solid-phase synthesis in air without the need for an inert or reducing medium. A nanostructured dispersive crystal composite is formed during the direct synthesis of LiFePO4/C, and its role in determining the specific discharge capacity of the synthesised powder is considered. The nanostructured composites are formed by bottom-up self-assembly, resulting in dispersive, crystalline globular solids with well-developed internal porosity. The conditions created during the continuous synthesis of LiFePO4/C in air have a dominant influence on the morphologies of the nanostructured composites, which adopt 'isometric' or 'platelet' forms. In the latter case, three- and six-faced channels may develop within their volume. Increasing the concentration of these nanostructured composites within LiFePO4/C powders helps prevent degradation in the specific charge capacity and enhances their absolute values while cycling.