Barium Doped Li2FeSiO4 Cathode Material for Li-Ion Secondary Batteries

Barium-doped Li2Fe(1-x)Ba(x)SiO4 (x = 0, 0.01) cathode materials were synthesized by the sol-gel and electrospinning processes. The structures of the samples were confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The sizes and the morphologies of the particles and nanofibers were observed by field emission scanning electron microscopy and atomic force microscopy. The initial discharge capacity of Li2FeSiO4 particles was 28 mAh/g, Li2FeSiO4 nanofibers and barium (Ba)-doped Li2FeSiO4 nanofibers showed the discharge capacities of 78 and 85 mAh/g, respectively. The lithium-ion diffusion coefficients of Li2FeSiO4 particles, Li2FeSiO4 nanofibers and Ba-doped Li2FeSiO4 nanofibers were calculated 5.15 x 10-(16), 3.52 x 10(-16), and 2.27 x 10(-15) cm2/s, respectively. The Ba-doped Li2FeSiO4 cathode material showed the highest lithium-ion diffusion coefficient, and its electrochemical properties were better than that of the pristine material.