PEG-assisted Solid State Synthesis and Characterization of Carbon-Coated Li2MnSiO4 Cathode Materials for Lithium Ion Battery

Phase-pure carbon-coated Li2MnSiO4 cathode material has been prepared through a PEG-assisted solid state reaction strategy. Transmission electron microscopy further confirmed that the Li2MnSiO4 nanocrystals (~50nm) were coated with amorphous carbon layer on their surface. The as-obtained Li2MnSiO4 cathode material exhibited the most initial discharge capacity of 204 mAh g-1 at the 10 mA g-1 current density at room temperature and the highest discharge capacity of 128 mAh g-1 at the 200 mA g-1 current density. Compared with PEG free Li2MnSiO4 cathode material, electrochemical performance of Li2MnSiO4 with PEG was greatly improved due to the pure phase, reduction in particle size. Influences of calcination temperature and PEG addition on phase purity, surface morphology as well as electrochemical performance were studied in detail, in which it was found that PEG as a dispersant made the slurry more uniform and stable during ball milling process and favored the phasepure Li2MnSiO4.