Electrical and electrochemical characterization of nano-sized LiFePO$_{4}$ cathode materials synthesized by a lauric acid-based sol--gel method

We synthesized pure LiFePO$_{4}$ and C-LiFePO$_{4}$ nanoparticles by sol-gel technique. Carbon coating was accomplished by including Lauric acid in the sol-gel precursor solution. Three C-LiFePO$_{4}$ samples of particle sizes 29, 27, 23 nm, were prepared by varying lauric acid concentration in the precursor solution.~ All the samples were~characterized~by X-ray diffraction, Raman, conductivity, and electrochemical measurements. The micro-Raman measurements showed two major bands at $\sim $1585 cm$^{-1}$ (G) and at $\sim $1345 cm$^{-1}$ (D) in all the C-LiFePO$_{4}$ samples.~ The 23 nm particle size sample showed minimum (D/G) band ratio and the maximum electrical conductivity among the three samples. The measured value of the capacity for 23 nm sized sample,~$\sim $170 mAh/g, approached the theoretical capacity limit value for LiFePO$_{4}$