High capacity Li[Ni0.8Co0.1Mn0.1]O2 synthesized by sol-gel and co-precipitation methods as cathode materials for lithium-ion batteries

Layered Li[Ni0.8Co0.1Mn0.1]O-2 cathode materials have been prepared by sol-gel and co-precipitation methods. The structural, morphological and electrochemical properties of the materials were compared. The XRD patterns show that both the sol-gel and the co-precipitation method formed single phase materials with good layered characteristics. Rietveld refinement reveals some differences in cation disorder between the two materials, where the sample synthesized by the sol-gel method shows lower Li/Ni cation disorder. SEM and BET measurements show that the sol-gel sample consists of relatively less aggregated particles giving larger BET surface area compared to the co-precipitation sample. Electrochemical tests indicate that the material prepared by the sol-gel method has slightly better electrochemical properties, with an initial discharge capacity of 200 mAh.g(-1) and capacity retention of 82.2% after 50 cycles at a cycling rate of 0.5 C, as well as better capability at 5 C. The improved performances of the sol-gel synthesized material may be attributed to the low Li/Ni disorder combined with high surface area, the latter increasing the interfacial contact area between the electrolyte and the active material. Effects of calcination conditions on the structure and electrochemical performance of the materials were also investigated. The electrochemical performance was improved by either increasing the O-2 concentration in the calcination atmosphere, or by increasing the flow rate of air, showing the potential of developing low-cost synthesis routes for high-quality cathode materials. (C) 2013 Elsevier B.V. All rights reserved.