Hydrothermal Synthesis of Li₂MnSiO₄ Powders as a Cathode Material for Lithium Ion Cells

Abstract

Li2MnSiO4 cathode materials were prepared by hydrothermal reaction at 150°C using LiOH, Si(OC2H5)4 and Mn(Ac)2.4H2O as raw materials followed by a low temperature heat annealing at 650°C. The samples were characterized by X-ray diffraction, scanning electron microscopy, FTIR. The powders electrochemical performance was investigated in terms of cycling behavior. Nanometer-sized flake crystalline particles of Li2MnSiO4 are obtained with some degree of agglomeration and little impure phases are detected after annealing. The charge capacity of the Li2MnSiO4 samples is 306 mAh/g (about 1.84 Li+ per unit formula extracted), and the discharge capacity is 114 mAh/g (about 0.68 Li+ per unit formula inserted) in the first cycle in the voltage range of 1.5–4.8 V under a rate of C⁄20. With increasing cycle number, the cell exhibits a well cycle performance with more than 95% coulombic efficiency and the maintenance of 61% of its discharge capacity after 50 cycles.

Synthesis, characterization and electrochemical performance of $$\hbox {Li}_{2}\hbox {Ni}_{x}\hbox {Fe}_{1-x}\hbox {SiO}_{4}$$ Li 2 Ni x Fe 1 - x SiO 4 cathode materials for lithium ion batteries

“…The doublet absorption band at 800 cm −1 is related to the monoclinic structure of Li 2 FeSiO 4 . The same peak splits into two stronger bands, which indicates the orthorhombic structure of Li 2 NiSiO 4 [31,32]. The other characteristic absorption bands at 1455 cm −1 are assigned to the Li 2 CO 3 formed at the surface [33].…”