Synthesis and electrochemical characterizations of La doped nano-size LiCo0.2Ni0.8O2cathode materials for rechargeable lithium batteries

Abstract

The LiLa x Co 0.20 -x Ni 0.80 O 2 , where x = 0.00, 0.01, 0.03, 0.05 and 0.10 cathode materials for rechargeable lithium ion batteries were synthesized by simple sol-gel technique using aqueous solutions of metal nitrates and polyvinyl alcohol. The gel precursors were dried in vacuum oven for 12 h at 120 °C. After drying, the gel precursors were ground and heated at 800 °C. The structural characterization was carried out by X-ray powder diffraction. The sample exhibited a well-defined hexagonal layered structure. Surface morphology and particle size of the synthesized materials was determined by scanning electron microscope and transmittance electron microscope and it was found that the cathode materials consisted of highly-ordered single crystalline particles with layered structure. Electrochemical properties were characterized by the assembled test cells using galvanostatic charge/discharge studies which were carried out at a current rate 0.1 C at potential range of 2.75 to 4.5 V. Among them, lanthanum doped LiLa 0.03 Co 0.17 Ni 0.80 O 2 has improved the structural stability, high reversible capacity and excellent electrochemical performance of rechargeable lithium batteries.