Synthesis of Mesoporous Ordered LiFePO4 /C Structures for Cathodes of Li-Ion Batteries

The LiFePO₄  phase has become a very promising cathode to be utilized in Li-ion batteries, as a result of its stability during intercalation, low toxicity, low cost and theoretical capacity of 170 mAhg^-1. Unfortunately, this compound possesses low ionic and electronic conductivities resulting in a low performance of the battery. Different strategies have been proposed to improve the conductivity of the material (e.g. doping, mixing with carbon particles, finer particles). Recently, the development of a structured mesoporous LiFePO₄/C has enabled to attain a larger specific capacity of 166 mAhg^-1 and longer lifetime. However, the maximum capacities of this compound have not been investigated at all. Therefore, this study is oriented to improve the synthesis process of a structured mesoporous LiFePO₄/C phase, in order to enhance the conduction and diffusion mechanisms. A structured mesoporous silica compound (SBA–15) is used as template for the fabrication of a mesoporous carbon structure, where the LiFePO₄  phase is impregnated. This material is then compared (performance of the LiFePO₄ in the battery) with that prepared using an alternative and faster synthesis route using activated carbon with large surface area.