Surfactant based sol–gel approach to nanostructured LiFePO4 for high rate Li-ion batteries

Porous nanostructured LiFePO4 powder with a narrow particle size distribution (100–300 nm) for high rate lithium-ion battery cathode application was obtained using an ethanol based sol–gel route employing lauric acid as a surfactant. The synthesized LiFePO4 powders comprised of agglomerates of crystallites <65 nm in diameter exhibiting a specific surface area ranging from 8 m2 g−1 to 36 m2 g−1 depending on the absence or presence of the surfactant. The LiFePO4 obtained using lauric acid resulted in a specific capacity of 123 mAh g−1 and 157 mAh g−1 at discharge rates of 10C and 1C with less than 0.08% fade per cycle, respectively. Structural and microstructural characterization were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) with energy dispersive X-ray (EDX) analysis while electronic conductivity and specific surface area were determined using four-point probe and N2 adsorption techniques.