Synthesis And Electrochemical Properties Research Of Electrode Materials In Lithium-Ion Batteries From Layered Precursors

Orthorhombic LiMnO₂ (o-LiMnO₂) and doped Li_x[Co_yMn₍1-y_]O₂ (y= 0.1, 0.3, 0.5) have been prepared from layered precursor by the method of in situ oxidation-intercalation for use as cathode materials in lithium-ion batteries. And a series of spinel MFe₂O₄ (M= Ni, Co, Ni-Zn, Zn) have been synthesized from layered double hydroxides (LDHs) precursors for use as anode materials in lithium-ion batteries. Reaction conditions, mechanisms, the relationships among structure, composition and electrochemical properties of materials were characterized by means of XRD, in situ HT-XRD, ICP, ⁷Li-MAS-NMR, FT-IR, TG-DTA-DTG-EGMS, TEM, HR-TEM and electrochemical testing. The factors which affect the electrochemical properties of materials were investigated.Using Mn(OH)₂ as the precursor, (NH₄)₂S₂O₈ as the oxidant and LiOH as the lithiating reagent, nanosized o-LiMnO₂ with high purity have been obtained by in situ oxidation-intercalation method. The o-LiMnO₂ has a high capacity with an initial charge capacity of 243 mAh.g^-1 an initial discharge capacity of 220 mAh.g^-1 and a good cycling performance with a reversible capacity of 192 mAh.g^-1 after 30 cycles.