Synthesis of La-doped Li2MnSiO4 nano-particle with high-capacity via polyol-assisted hydrothermal method

Li 2 Mn 1 La x SiO 4 /C (x   =   0, 0.01 and 0.04) composites are prepared via a polyol-assisted hydrothermal method followed by carbon coating. X-ray diffraction patterns confirm that the unit cell volume of Li 2 MnSiO 4 has been enlarged by doping a small amount of La 3+ . The scanning electron micrographs and elemental maps indicate that the sizes of the Li 2 MnSiO 4 particles can be reduced by homogeneously doping La 3+ . The transmission electron microscopy shows the well crystallized Li 2 MnSiO 4 nanoparticles. The electrochemical performances of all samples are evaluated by galvanostatic charge/discharge tests and electrochemical impedance spectroscopy. 1   at.% La 3+ doped Li 2 MnSiO 4 (AL1) delivers the highest initial discharge capacity of about 257   mAh   g −1 , corresponding to the intercalation of about 1.55 lithium ions per formula unit. AL1 also exhibits improved capacity retentions of about 51.1%. The above improvements of electrochemical properties are related to the decreased charge transfer resistance and enhanced lithium ion diffusion for La-doped samples, whose crystal structure is maintained and lattice has been slightly enlarged.