Solvothermal synthesis of LiFePO₄ hierarchically dumbbell-like microstructures by nanoplate self-assembly and their application as a cathode material in lithium-ion batteries

In this work, LiFePO₄ with hierarchical microstructures self-assembled by nanoplates has been successfully synthesized by using poly(vinyl pyrrolidone) (PVP) as the surfactant in a benzyl alcohol system. The resulting dumbbell-like LiFePO₄ microstructures are hierarchically constructed with two-dimensional nanoplates with ̃300 nm length and ̃50 nm thicknesses, while these tiny plates are attached side by side in an ordered fashion. Both benzyl alcohol and LiI acting as reducing agents promote the formation of LiFePO₄, and the presence of PVP plays an important role in the construction of the hierarchically self-assembled microstructures. A reasonable formation mechanism is proposed on the basis of the result of time-dependent experiments. In addition, the cell performance of the synthesized LiFePO4 is better than that of the commercial LiFePO₄, which makes it a promising cathode material for advanced electrochemical devices such as lithium-ion batteries and supercapacitors.