Highly ordered LiFePO4 cathode material for Li-ion batteries templated by surfactant-modified polystyrene colloidal crystals

An organic template assisted synthesis was developed to obtain highly ordered porous LiFePO4 cathode material. The developed synthesis enabled the use of polystyrene (PS) as template by modifying its surface with a surfactant (Brij 78) to render it hydrophilic. The material was synthesized in high yield and purity as confirmed by X-ray powder diffraction. The TEM and SEM images clearly confirmed the presence of a highly ordered porous structure and the latter showed that the structure has an average pore diameter of 400 nm and a wall thickness and depth of ∼100 nm. Thermal scans and elemental analysis showed that the material contains a high amount of carbon reaching 23–28% by weight. The surface area was calculated using the BET method and found to be 7.71 m2 g−1. Li/LiFePO4 half cells were tested and gave satisfactory discharge capacities; an initial capacity (158 mAh g−1) close to the theoretical value and recoverable capacities at high C-rates (2–5 C).

► New synthesis of three dimensionally ordered macroporous (3DOM) LiFePO4/C was developed. ► The template polystyrene was rendered hydrophilic by modifying the surface with a surfactant. ► High yield of 3DOM LiFePO4 was produced with new synthesis. ► 3DOM LiFePO4 showed satisfactory capacities in lithium batteries.