PVP-assisted synthesis of LiFePO4/C cathode material for Li-ion storage

In this study, a solution combustion synthesis method was employed using polyvinylpyrrolidone (PVP) as fuel to prepare LiFePO4 (LFP) powders. The effects of PVP contents on the structural, microstructural, and electrochemical properties were investigated by various characterization methods. The as-combusted powders were calcined at 750 degrees C for 6 h under an Ar-5% H-2 atmosphere, resulting in the well-crystalline LiFePO4 powders without any impurity alpha-Fe2O3 and Fe2P phases. The LFP powders were composed of large spherical LiFePO4 particles (1 mu m) in which the specific surface area and pore size were dependent on the PVP fuel content. The LFP powders prepared by a mass ratio of PVP to metal nitrate of 3 had the highest specific surface area of 328 m(2 )g(-1), leading to excellent cycling performance such as a stable coulombic efficiency of 100% and a high capacity retention of 92% (from 84 to 78 mAh g(-1)) for 500 charge/discharge cycles at a current rate of 1C.