Solvothermal synthesis and self-assembling mechanism of micro-nano spherical LiFePO4 with high tap density

Abstract

Although LiFePO₄ has been widely studied and also used as a promising cathode material for Li ion batteries, its inferior tap density is still a big challenge for practical application. Well-defined three-dimensional porous LiFePO₄ microspheres composed of nanosheets were successfully synthesized by a simple one-step solvothermal method. The porous spherical morphology could not only retain the excellent electrochemical performance characteristics of the LiFePO₄ nanosheet but also meet the requirements of high tap density of the powder particles, leading to highly improved volumetric energy density. These micro-nano structured LiFePO₄ microspheres have a high tap density of about 1.4 g cm⁻³. A growth mechanism is also proposed based on time-dependent experiments. This work provides an efficient route for designing a desirable micro–nano structure, which could also be extended to synthesize other hierarchical structures used in different fields.