Electrochemical performances of co-substituted (La and Li) LiLax−yLiyNi1−xO2 cathode materials for rechargeable lithium-ion batteries

• LiLax−yLixNi1−xO2 powders were prepared by a sol–gel method at 600 °C for 10 h.
• LiLax−yLixNi1−xO2 powder materials had well defined layer structure, and no impurities.
• LiLa0.10Li0.10Ni0.80O2 crystallite size was reduced compared with those of LiNiO2.
• Li/LiPF6/LiLax−yLixNi1−xO2 cells were of high charge/discharge capacity, with columbic efficiency at 25 °C and 45 °C.
• LiLa0.10Li0.10Ni0.80O2 good cyclic stability, rate capability and better 45 °C.

Co-substituted LiLax−yLiyNi1−xO2 cathode materials were synthesized by sol–gel method using aqueous solutions of metal nitrates and tartaric acid as chelating agent at 600 °C for 10 h. The structure and electrochemical properties of the synthesized materials were characterized by using XRD, SEM, EDAX, TEM, cyclic voltammetry, charge/discharge and electrochemical impedance spectroscopy. XRD studies revealed a well defined layer structure and a linear variation of lattice parameters with the addition of lanthanum and lithium confirmed phase pure compounds in a rhombohedral structure. TEM and SEM analysis shows that LiLa0.10Li0.10Ni0.80O2 has smaller particle size and regular morphological structure with narrow size distribution than those of LiNiO2. Variations of dual mixing and hexagonal ordering with the substituted elements have enhanced the charge/discharge capacities at both room (25 °C) and elevated temperatures (45 °C), respectively. LiLa0.10Li0.10Ni0.80O2 had high charge/discharge capacity, low irreversible capacity and better elevated temperature performance.

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